Anal. Chem. 1903, 65, 244R-292R
Water Analysis? Patrick MacCarthy’ and Ronald W. Klusman Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401 Steven W . Cowling Environmental Science and Engineering, Inc., 7330 South Alton Way, Englewood, Colorado 80112 James A. Rice Department of Chemistry, South Dakota State University, Brookings, South Dakota 57007 Review Contents INTRODUCTION INORGANIC ANALYSIS Alkali and Alkaline-Earth Metals (and Ammonium Ions) Barium Beryllium Calcium Magnesium Calcium and Magnesium Strontium Potassium Cesium Sodium Potassium and Sodium Ammonium Ions Multiple Alkali and Alkaline-Earth Metals Other Alkali Metals TRANSITION METALS First Series Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Multiple First Transition Series Metals Second Series Molybdenum Tungsten Precious Metals Silver Gold Palladium Other Platinum Group Metals Lanthanides (Rare-Earth Elements) Group 12 Metals Zinc Cadmium Mercury Multiple Group 12 Metals Group 13 Elements Aluminum Gallium Indium Group 14 Elements Tin Lead 2441
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Group 15 Elementa Arsenic Antimony Bismuth Multiple Group 15 Elementa Nonmetals Boron Silicon Germanium Selenium Tellurium Radionuclides Radium Radon Other Radionuclides Actinide Elementa Thorium Uranium Multiple Metals Anions Sulfur Anions (SO&, SO,+-, S20s2, S”) Nitrogen Anions (NOS-, NOz-) Phosphorus Anions (PO4”, P20,4, HP03-, H2P02-) Arsenic Anions (As(III), As(V)) Halides and Oxyhalides (F-, C1-, B r , I-, C10-, C102, ClO”, BrO”, IO”) Carbonate and Bicarbonate Cyanide Multiple Anions GASES Ammonia Oxygen and Ozone Chlorine and Chlorine Oxides Other Gases Miscellaneous ORGANIC ANALYSIS Gas Chromatography Reviews Instrumental Techniques Sample Introduction Stationary Phases Detection Organic Acids Nitrogen-Containing Compounds Miscellaneous Compounds Liquid Chromatography and High-Performance Liquid Chromatography Instrumentation Phenols and Related Compounds Nitrogen-Containing Compounds Miscellaneous Compounds @ 1993 American Chemlcal Society
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Mass Spectrometry Reviews Liquid Chromatography-Mass Spectrometry Membrane-Introduction Mass Spectrometry Gas Chromatography-Mass Spectrometry Mobile Mass Spectrometers for On-Site Analysis Miscellaneous Compounds Photometry and Spectrophotometry Reviews Fluorescence Phosphorescence Flow Injection Analysis Miscellaneous Methods Miscellaneous Compounds In-Situ Sensors for Water Monitoring Reviews Aromatic Hydrocarbons Chlorinated Hydrocarbons Hydrocarbons Miscellaneous Biochemical Methods Reviews Atrazine Chlorinated Pesticides Phosphorous-Containing Pesticides Urea-Containing Pesticides Miscellaneous Methods Sampling, Preconcentration, Extraction, and Separation Reviews Sampling Solid-Phase Extraction Resin-Based Extraction Miscellaneous Volatile Organcic Compounds Reviews Sampling, Extraction, and Preconcentration EPA Methods Miscellaneous Methods Pesticides, Herbicides, and Fungicides Reviews Sampling, Preconcentration, Extraction, and Separation Solid-Phase Extraction Graphitized Carbon Black Membrane Disk Extraction Liquid-Liquid Extraction Miscellaneous Techniques Gas Chromatography Liquid Chromatography Organic Acids Organophosphorus Pesticides Carbamates Miscellaneous Thin-Layer Chromatography Spectroscopic Methods Mass Spectrometry Electrochemical Methods Miscellaneous Methods Organometallic Compounds Reviews Organotin Compounds
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Reviews Sampling, Extraction, and Preconcentration Gas Chromatography High-Performance Liquid Chromatography Miscellaneous Organolead Compounds Organoselenium Compounds Organoarsenic Compounds Organoantimony Compounds Organomercury Compounds Surfactants and Detergents Reviews Spectroscopic Methods Chromatographic Methods Mass Spectrometry Miscellaneous Methods Hydrocarbons Reviews Sampling, Extraction and Preconcentration Chromatographic Methods Spectroscopic Methods Miscellaneous Methods Other Methods Reviews Ion Chromatography Thin-Layer Chromatography Chlorophyll Electrochemical Methods Organic Elemental Analysis Capillary Electrophoresis Miscellaneous LITERATURE CITED
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INTRODUCTION T h i s is the 25th biennial review dealing with the inorganic and organic analytical chemistry of water. The format of this review is similar to that of the previous review in this series, which was published in Analytical Chemistry in 1991 (I). However, there a r e some differences in the contents, particlularly in the Organic Analysis section of the review. The references used in preparing this review were compiled by a computer search of Chemical Abstracts covering the period from where the previous review ended (Vol. 113 (24), December 10,1990)through Vol. 117(22), November 30,1992. The references in this review represent a selection of the approximately 4554 citations examined for this period. These citations are t h e result of the computer search based o n a combination of keywords relevant t o water chemistry. A total of 1485 references are cited in this review from t h e 4554 references that were consulted. Certain criteria a r e used b y the authors in making these choices. In brief, if an abstract is unclear or ambiguous i t is generally excluded. If the subject m a t t e r appears to be of a routine nature, without the introduction of novel features, i t is also likely to be omitted; however, novel combinations of existing techniques may constitute a new contribution and qualify for inclusion in this review. The reader is referred t o the Introduction t o the previous review (1) in this series for a more detailed presentation of these criteria and a more complete discussion of the philosophy and scope of these Water Analysis reviews. For papers describing quantitative determinations, t h e authors of this review pay particular attention t o the inclusion of i m ortant analytical data relatin t o accuracy (e.g., use of stanzards), precision (standard Jeviation, coefficient of variation, etc.), number of replicates, limits of detection, +Anabbreviatedversionof citations in Chemical Abstracts is given in the references. If expanded, the correct citation would be (for example, in ref A l ) Chem. Abstr. 1992,117, 137217e. ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
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Patrlck MacCarthy is Professor of C h e m istry at the Colorado School of Mines. He received B.Sc. and M.Sc. degrees in chemistry from University College Galway, Ireland, an M. S. degree in chemistry from Northwestern University, and in 1975 a Ph.D. in analytical chemistry from the University of Cincinnati. His principal research interests are in soil and water chemistry with a particular emphasis on humic substances. MacCarthv is coeditor of the books Humic Substanks in Soil, Sediment, and Water(Wiley, 1985), Humic Substances. 11: I n Search of Structure (Wiley, 19891, Aquatic Humlc Substances (American Chemical Society, 1989), and Humic Substances In Soiland Crop Sciences (American Society of Agronomy, 1990). RonaldW. Klusman is presently Professor of Chemistry and Geochemistry and Professor of Environmental Sciences and Engineering at the Colorado School of Mines. He received his B. S. degree in 1964 and Ph.D. degree in 1969, both from Indiana University. He is a member of the American Association for the Advancement of Science, American Association of Petroleum Geologists, American Geophysical Union, Association of Petroleum Geochemical Explorationists, The Association of Exploration Geochemists, and The Geochemical Society. Research interests include environmental geochemistry, water quality related to mining, sampling design applied to large, heterogeneous systems, and soil gas techniques applied to petroleum, mineral, and geothermal prospecting. He is author of a book entitled Soil Gasand Related Methods for Resource Explorationwhich is currentty in press (Wiley, 1993).
Steven W. Cowllng is a Project Laboratory Scientist in the Denver laboratory of Environmental Science and Engineering, Inc., where he is involved in HPLC method development and certification. He received his Ph.D. in applied chemistry from the Colorado School of Mines in 1991.
James A. Rlce is an Associate Professor of Chemistry at South Dakota State University. He received a BA degree in natural sciences from St. John’s University (MN) and M.S. and Ph.D. degrees in geochemistry from the Colorado School of Mines. His research interests include the applications of organic analytical chemistry to environmental geochemistry, the geochemistry of the humin fraction of humus, and the analytical chemistry of complex mixtures of organic molecules.
sensitivity, linear range or useful range of the technique, sampling rates, selectivity, the nature of interferences, recoveries, sample sizes to which the method is applicable, and so on. Papers are more likely to be cited in this review if data relating to accuracy and precision as well as other operational parameters are provided in the abstract found in Chemical Abstracts. Certain substances or classes of substances may appear a t more than one location in this review. For example, if one is interested in the analysis of nitrogen compounds in water, useful information may be found in several subsections of the InorganicAnalysis section. Ammonium is included in the Alkali and Alkaline-Earth Metals section because of the chemical similarity of ammonium to the alkali metal ions. 246R
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Information on NH3 in water is also included in the subsection entitled Ammonia in the Gasessection. Additionally,analysis of nitrogen compounds can be found in the Nitrogen Anions section. Analysis of nitrogen-containingcompoundsmay also be found a t several locations throughout the OrganicAnalysis section of this review. For example, a subsection entitled Nitrogen-Containing Compounds appears in the section on Liquid Chromatographyand High-Performance Liquid Chromatography, and analyses of nitrogen-containingcompounds are also discussed at several other locations such as in the subsections entitled Atrazine, Urea-Containing Pesticides, and Carbamates. A table of contents is included to aid the reader in using this review. INORGANIC ANALYSIS Alkali and Alkaline-Earth Metals (and Ammonium Ions) Barium. Barium was determined in water in the ppm concentration range by stripping voltammetry after elimination of interference from magnesium by treating the water samples with 8-hydroxyquinoline (AI). In another study, a lower detection limit of 1.7 mg of Ba/L in wastewater was achieved using flame atomic absorption spectrophotometry (FLAAS). An air-acetylene flame was used rather than electrothermal atomization to avoid forming barium carbide in the graphite furnace (A2). Beryllium. A spectrophotometric method for Be in groundwater was reported which used vanillylfluorone in the presence of cetylpyridine bromide as the color agent. The absorbance was measured a t 552 nm, and the linear range for the method was 0-2.0 pg of Be/mL (A3). In another spectrophotometric method, Be was first precipitated as beryllium ammonium phosphate in acidic solution. The precipitate was dissolved in hot, dilute HN03 and reduced with malonyl dihydrazide to molybdenum blue. The absorbance at 780 nm was linear in the range of 0.1-0.8 ppm Be (A4). A similar method was reported in which succinyldihydroxamic acid was used to reduce the dissolved precipitate, and the absorbance was measured a t 820 nm. The linear range was 0.1-0.8 ppm Be (A5). Chrome Azurol S and cetylpyridinium chloride were used in another spectrophotometric method for Be in which interfering ions were eliminated by adsorption on activated carbon. Beer’s law was obeyed a t 605 nm in the range of 0-0.7 pg of Be in 25 mL (A6). Beryllium was concentrated on a glass-fiber filter, then desorbed, and fixed on a membrane filter as the complex formed with Chromazurol B in the presence of hexadecyltrimethylammonium bromide. The absorbance of the fixed complex was determined directly by solid-phase spectrophotometry. The detection limit was 0.4 ng for 30 cm3of sample ( A n . The fluorescence of the Be-morin complex was used to determine the concentration of Be in water in the range 0.6-87.5 pg of Be/L (A8). Spectrofluorometryof the beryllium complex with 2-hydroxy-3-naphthoic acid was used to determine Be in natural waters in the range of 0.01-0.50 pg of Be/L. A 500-mL sample was preconcentrated on silica gel to achieve a detection limit of 0.006 pg of Be/L (A9). A method was reported in which the complex of Be formed with Chrome Azurol S in the presence of tetradecylpyridine bromide was concentrated by adsorption on activated carbon and then desorbed and the Be determined by fluorescenceof the morin complex (AIO). Berylliumwas reported to form a 1:lcomplex with chlorophosphonazo-mA,which fluoresces a t 614.4 nm and can be used to determine Be in environmental water samples ( A l l ) . A method for determining Be by FLAAS included a solvent extraction step to remove interferences and isolate the Be. N-benzoyl-N-phenylhydroxylaminewas used to extract Be into methyl isobutyl ketone (MIBK),and the organic phase was aspirated directly into an N20-C2H2 flame. A detection limit of 2 ng of Be/mL and a linear range of 0-1.0 pg of Be/mL were reported (A12). A method was reported for the determination of Be by ion chromatography. Beryllium is quantified by postcolumn derivatization with Beryllon I1and spectrophotometric detection at 625 nm. The detection limit for a 50-pL sample was 42 pg of Be/L (A13). An adsorptive stripping voltammetry method for Be was reported in which the Be complex with Beryllon I1 was determined using a fast-scan differential pulse technique. The method was applied to beryllium determination in the concentration range of 10-8-10-6 mol of Be/L (A14).
WATER ANALYSIS
Calcium. Dibromoalizarin violet was reported as an indicator for calcium in complexometric titrations. The stability constant for the 1:l complex was 2.3 X lo5 (A15). Calcium was determined spectrophotometrically with mbromoantipyrylazo, one of eight antipyrylazo color reagents tested. The com lex absorbs at 630 nm in NaOH media, with Beer’s law oteyed in the range of 0-30 pg of Ca/25 mL (A16). Amino G acid chlorophosphonazo was also used in the spectrophotometric determination of Ca. This reagent forms a complex with Ca which has a molar absorptivity of 5.7 X l o 4 L mol-’ cm-l a t 666 nm. Beer’s law was obeyed in the range of 0-20g of Ca/25 mL (AI 7 ) . Aspectro hotometric flow injection method was described which was Eased on the reaction of Ca with Chlorophosphonazo 111. The calibration curve was linear up to 1.2 ppm Ca, with a detection limit of 0.01 ppm Ca for a sample volume of 120 pL (A18). A Ca ion-selective electrode based on tetra(o-tolyl)-o-xylyldiphosphine dioxide was described which was highly selective for Ca and was used to measure Ca ion concentrations in the range of 10-1-10-5 M (A19, A20). A titrimetric method for determining Ca and Sod” in a single sample was reported. The procedure was able to determine 0.1 mg of Ca2+and 0.25 mg of S042-(A21). Magnesium. The rate of enzymic formation of NADPH through M -ATP was used to determine the concentration of Mg in kine. The calibration curve was linear up to approximately 100 mg of M /L (A22). Another enzymic method for determining M ased on the oxidative decarboxylation of isocitric acid %y NADP-dependent isocitrate dehydrogenase was reported. The detection limit was 0.24 n of Mg/mL (A23). Magnesium was determined spectropEotometrically by measuring the absorbance of the Mg complexformed with dibromophenylfluorone in the presence of cetyltrimethylammonium bromide. Beer’s law was obeyed at 640 nm for 0-4 pg of Mg/25 mL (A24). Flow injection spectrophotometry at 635 nm was used to determine Mg in water using Eriochrome Azurol B and cetyltrimethylammonium chloride. The calibration curve was linear for 0.2-1.0 mg of Mg/L (A25). Calcium and Magnesium. Simultaneous spectrophotometric determination of Ca and Mg using 4-(2-pyridylazo)resorcinol was reported. A multilinear re ession program was used to resolve the absorbance ban and determine the concentration of each metal ion. The method provided linear ranges of 0.10-4.0 pg of Ca/mL and 0.15-2.5 p of Mg/mL (A26). A flow injection method using 4-(pyridyl-2-azo)resorcinol and a photometric diode array detector was reported capable of analyzing 70 samples/h, with linear ranges of 1-10 mg of Ca/L and 1-20 mg of Mg/L (A27). A flow injection system for simultaneous determination of Ca and Mg used simultaneous injection of a plug of ethylene lycobis(2aminoethyl ether)-N,N,N‘,N’-tetraaceticacid and two small sample plugs in the same carrier stream. This stream was merged downstream with 3,3‘-bis[N,N-bis(carboxymethyl)aminomethyl)]-0-cresolphthalein, and Ca and Mg were determined spectrophotometrically. The rate of analysis was about 15 samples/h (A28). Calcium and magnesium were determined b FLAAS after coprecipitation with zirconium hydroxide. Tze linear ranges were 0.04-10ppm Caand 0.0020.3 ppm Mg (A29). A method was reported for sequential determination of Ca and M by pH titration using the tetrasodium salts of EGTA a n f EDTA (A30). An automated system was developed for determination of Ca and Mg by coulometric titration. The method was based on release of EDTA from its Hg complex upon electrochemical reduction of the Hg2+ion (A31). Radium. See Radionuclides. Strontium. Strontium was determined photometrically at 671 nm following precipitation with ammonium carbonate and dissolution of the precipitate with dilute HC1. Correction for interference by calcium was made by a separate Ca determination (A32). A FLAAS method for Sr was reported in which the metal was concentrated by ion exchange and eluted with 3 7% EDTA. The EDTA su pressed interferences, and the detection limit was 1.6 pg of #r/L (A33). Thin-layer chromatography on silica gel or cellulose pretreated with calcium oxalate was used to separate strontium and yttrium. Radioactivity of the separated elements was measured (A34). Potassium. An extraction photometric method for determining K was reported in which a water sample was shaken
%
B
with an ethanolic solution of di icrylamine and a toluene solution of dibenzo-18-crown-6 Pollowed by measuring the absorbance of the organic layer a t 420 nm. The linear range was (0.4-8) X 10-5mol of K/L (A35). Crown ether complexes of the alkali metals were found to be less soluble than the metals themselves in the presence of tetraphen lborate. A flow injection method for determining K was deveLped based on this precipitation reaction. The calibration graph was linear in the range (0-1)X 10-4 M K+. With this method, 30 samples could be processed in 1h (A36). A capillary stream sensor for determining K was developed based on membrane solvent extraction usin crown ether and microporous tubing. The sensor was appliefto both continuous-flow analysis and flow injection analysis. The continuous-flow analysis procedure was used to analyze environmental waters in the range of 1 X 10-5-1.2 X 10-4 M K+ (A37). A valinomycin-based K-selective membrane electrode was developed for analysis of K in seawater (A38). Potassium was determined by preci itation with “C-labeled sodium tetraphenylborate, dissorution of the precipitate in a liquid scintillation mixture, and simultaneous measurement of the @ radiation of 14C and 40K (A39). Cesium. A turbidimetric method for Cs was developed using sodium tetraphenylborate as a precipitating reagent (A40). In another study, a single-swee oscillopolaro raphy method for indirect determination of 8 s was reportef. The method is based on precipitation of Cs with Bib-, which yields a polarographic derivative wave at -0.24 V vs SCE. Cesium was first extracted from brine with ammonium phosphomo(A41). l3’Cs lybdate and 4-sec-butyl-2(cr-methylbenzyl)phenol was concentrated on ammonium mol bdophosphate and precipitated as CszPtCb for @-activity&termination (A42). MCs and l3’Cs were adsorbed on freshly prepared Cu2Fe(CN)6 and determined by y spectrometry (A43). Sodium. An on-line,continuous analyzer using an electrode pair was developed to measure Na in high-purity waters (AM). A sodium-selective membrane electrode, based on 4’-tertbutylcyclohexano-12-crown-4,was reported to yield a detection limit of 5 X 10-5 mol of NaCl/L (A45). Potassium and Sodium. Flow injection analysis (FIA) methods for Na and K were reported in which alkali metalcrown ether complexes and an anionic dye were extracted into an organic phase, and the absorbance of the organic liquid was measured at 615 nm (A46, A47). Addition of cesium reduced interferences in determining Na and K by atomic absorption spectrometry (AAS) a t the 1-5 ppm level (A48). Ammonium. Ammonium was determined spectrophotometrically after extraction into chloroform as the complex with cryptand(2.2.2) and dithizone. Beer’s law was obeyed at 496 nm for up to 1pg of NHdcm3, with a detection limit of 0.13 pglcm3 (A49). An optical sensor for determining NH4+ in water was developed which gave a detection limit of 3 pmol of NH4+/L(A50,A51). A colorimetric method for NH4+ used indophenol and laser photothermal detection to achieve a detection limit of K0.25 mmol of NH4+/m3 (A52). A fluorometric method for ammonium was developed based on conversion of NH4+ to NH3 and reaction with o-phthaldialdehyde to form a fluorescent adduct. The lower detection limit was less than 1.5 mM (A53). A FIA system capable of determining NH4+ at 50 pg/L was developed which used Nessler reagent following preconcentration on a cation exchange column. An analysis rate of 45 samples/h was achieved (A54). An automated flow injection system for determining ammonium was described in which the sample is reacted with sodium salicylate, sodium nitroprusside, and NaClO, with the absorbance of the resulting solution measured at 660 nm. The calibration graph was linear up to at least 3.0 mg of NH4+-N/L (A55). A method was reported in which ammonium was oxidized to NOz- by NaBrO prior to reverse FIA with spectrophotometric detection. The detection limit was 0.13 rmol of NH4+/L, and the analysis rate was 60 samples/h (A56). Ammonium was determined by highperformance liquid chromatography (HPLC) using a nitrogenspecificchemiluminescencedetector (A57). A cation exchange resin was used in the HPLC separation of ammonium and primary amines from seawater. After separation, the compounds were labeled with a reagent containing o-phthalaldehyde and 2-mercaptoethanol and detected fluorometrically. The detection limit for primary amines and ammonium was approximately 0.1 pM (A58). Ammonium was concentrated ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
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on a cation exchange resin and then determined by suppressed ion chromatography with conductimetric detection. The linear range was 0.02-10 m of NH4+-N/L(A59). An ammonia as sensor was developef for determining NH4+ in water. khe sensor was reported to have a longer lifetime than conventional NH3 sensors and gave a linear response in the range of 0.05-100 m of NHr+/L (A60). An ion-selective electrode method for Sirect determination of NOS-and NH4+ was reported (A61). An enzymic UV method for determining NH4+ in rainwater was also presented (A62). Multiple Alkali and Alkaline-Earth Metals. Graphite furnace atomic emission spectrometry was used to determine Rb and Cs (A63). Flame emission photometry was used for determining Li, Cs, Sr, and Ba in drinking water and wastewater (A64). A spark emission spectrometer combined with a HPLC injection system and pump was used to determine Na, K, and Ca in the range of 0.1-10 000 mg/L (A65). Mg, Ca, and Sr in brine were determined by suppressed ion chromatography ( A M ) . The preparation, properties, and applications of polymer-coated cation exchangers for use in determining alkali and alkaline-earth metals were described (A67). Ion chromatography with electronic su pression was used for determining Li, Na, K, Ca, Mg, and l r in drinking water (A68). Stationary phases coated with micellar bile salt were used for separating monovalent and divalent cations by ion chromatography (A69, A70). Several other ion chromato raphic determinations of alkali and alkaline-earth met& were discussed (A71-A73). Other Alkali Metals. A method for determining Li in water by concentration on a cation exchange resin followed by AAS was reported (A74). A flame photometry method for determining Li used extraction of the Li as the thenoyltrifluoroacetone com lex with tributyl phosphate for preconcentration. With tRis method, Li could be determined at the 1 ppb level (A75). A GFAAS method for determining Rb with a detection limit of 0.03 ppb Rb was also reported (A76).
TRANSITION METALS First Series. Titanium. A spectrophotometric method pyrocatechol for the using 4- [(6-bromo-2-benzothiazolyl)azol determination of Tiin wastewaters wasdescribed ( B l ) . Ti(1V) forms a complex which gave a linear response at 570 nm for a com osition range of 0-520 pg of Ti/L. Another report descrifed the same reagent for the spectrometric determination of Ti at 555 nm and reported Beer’s law was followed in the concentration range of 20-560 pg of Ti/L (B2). Titanium was determined in seawater by cathodic stripping voltammetry (B3). A detection limit of 0.0003 pg of Ti/L for a 60 s adsorption time and of 0.000 05 pg of Ti/L for a 600-s adsorption time were reported. Vanadium. Vanadium was determined in seawater by acidic extraction with Chelex 100resin, followed by microwave dissolution of the resin with H2SO4-Hz02 to overcome difficulties with desor tion of the V (B4). The V was determined by ICP-AE! with a detection limit of < 0.2 pg of V/kg of seawater. Preconcentration of V from natural waters with chelating functional group immobilized on silica els was described (B5).Separation of V(1V) from V(V) coulr!be accomplished with two columns in series, with separation and recoveries in the range of 91-105%. The V was determined by ICP-AES with a detection limit of 6 ng/L. Vanadium was preconcentrated at a pH of 4.0-5.0 to concentrate the analyte on a small amount of activated carbon (B6).Addition of 8-quinolinolto the aqueous phase increased the effectiveness of recovery. The recovered V was determined by electrothermal atomic absorption spectrophotometry with a detection limit of 0.045 p of V/L. Natural waters with a concentration of 2.9 pg of V/L%ad a relative standard deviation of 10%. Derivative adsorption voltammetry was used to determine Vinnaturalwaters (B7). TheV(V) complexwith2-(5’-bromo2’-pyridylazo)-5-(diethylamino)phenolwas adsorbed on a dropping mercury electrode. The detection limit was 1.3 ng of V/L and there was a linear response from 25 to 10 000 ng of V/L. A similar method using 2-(3,5-dibromo-2-pyridylazo)5-(diethylamino)phenol, with diphenylguanidine, NaBrOa, and CICH&OOH-CICHzCOONaat a pH of 3.0 was described (B8). A linear response in the range of 0.04-18 pg/L was reported. 248R
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A catalytic-kinetic spectrophotometric method for the determination of V was described (B9). The reaction between Evans blue and KBr03 is catalyzed by V in hot dilute HaSO4 in the presence of ascorbic acid. The absorbance is decreased with time in the presence of V, and a detection limit of 0.22 ng of V/L was reported. Another method used the V(V)catalyzed oxidation of p-nitrophenylhydrazine by KC103 for the determination (B10). The absorbance was measured at 515 nm and Beer’s law was followed in the range of 0.0250.35 ng of V/L. Flow injection analysis was coupled with catalytic-kinetic spectrophotometry for the determination of V in natural waters ( B l I ) . The V catalyzes the oxidation of gallic acid by KBr03. The FIA allowsfor the determination of V in samples at 90/h. Recoveries were in the range of 89-100 % for samples in the 2 pg of V/L range and the relative standard deviation was 2.7%. Another method described the use of an iodide ion-selective electrode for the determination of V-catalyzed oxidation of dehydroascorbic acid by bromate and I- (B12). The reaction converts BrOs- and I- to B r and 13-, which is monitored with the I- ion-selective electrode. A detection limit of 25 ng of V/L was reported. Chromium. The determination of Cr in seawater by electrothermal atomic absorption spectrophotometry has numerous difficulties related to salinity of the samples and the condition of the graphite tubes (B13). Magnesium nitrate was used as a matrix modifier for low to medium salinity samples, which gave a detection limit of 0.05 pg of Cr/L. Na2W04was satisfactory as a matrix modifier over all sample salinity ranges, but ave a higher detection limit of 0.1 pg of Cr/L. These methois are suitable for the determination of Cr in somewhat polluted waters. Zeeman atomic absorption spectrophotometry was used for the determination of Cr in seawater (B14). Various reagents, includin ascorbic acid, triaminecitrate, and tartaric acid were user! to reduce the matrix effect on the Cr signal. Both ascorbic acid and triaminecitrate were effective alone, and in combination. Recoveries on seawater standards of 92-109 5% and a detection limit of 0.1 pg of Cr/L were reported. Separation and direct determination of Cr(II1) and Cr(V1)by electrothermal atomic absorption spectrophotometry was reported (B15). Cr(II1) is extracted with tetramethylammonium hydroxide and sodium acetate and then volatilized a t 400 OC in the graphite tube. The remaining Cr(V1) is determined by heating the graphite tube to 1200 “C. Recoveries of Cr(II1 + VI) were 96-108% and of Cr(V1) were 98-108%. The detection limit is 0.01 n of Cr. Chelate coprecipitation of Cr from samples was usecf for the concentration of Cr prior to determination by electrothermal atomic absorption spectrophotometry (B16).Several coprecipitation carriers were examined, with Mn(I1)-diethyldithiocarbamatefound to be the most effective. Recoveries of Cr(II1) and Cr(V1) from natural waters were reported in the range of 85-97 5%. Zinc sulfate in a sodium acetate buffer was used with zinc-diethyldithiocarbamate for the coprecipitation of Cr(V1) from natural waters (B17). The precipitate was collected on a 0.45-pm filter and subsequently dissolved with ethyl acetate. The Cr was determined by electrothermal atomic absorption spectrophotometry with a detection limit of 0.014 pg of Cr. Separation of Cr(II1) and Cr(V1) was accomplished by flow injection analysis using an alumina column, which in turn were determined by flame atomic absorption spectrophotometry (B18).Detection limits were not given, but recoveries were reported in excess of 100% for both Cr(II1)and Cr(V1). Cr(II1) was concentrated on a poly(hydroxam1cacid) resin and flow injection analysis performed (B19).The Cr was determined by flame atomic absorption spectrophotometry, and the method was applied to the analysis of seawater samples. The coupling of flow injection analysis and electrothermal atomic absorption spectrophotometry for the determination of Cr(V1) and total Cr was described (B20).Sodium diethyldithiocarbamate was used as the complexing a ent with Cu-bonded Si02 reversed-phase sorbent as a coumn material. The method had a detection limit of 16 ng/L for Cr(V1) and 18 ng/L for total Cr. The same authors used activated alumina to separate Cr(II1) and Cr(V1) followed by flame atomic absorption spectrophotometric determination of Cr (B21). Recoveries were in the range of 90-106 % and the detection limits were 1.0 pg of Cr(III)/L and 0.8 Kg of Cr(VI)/L, respectively. A complexation method using 1,5-diphenyl-
f
WATER ANALYSIS
carbazide was used for the determination of Cr(V1) (B22). The Cr(V1) complex was extracted for determination by absorption spectrophotometry, while total Cr was determined by atomic absorption spectrophotometry. The detection limit was 5 pg of Cr(VI)/L. Anion exchange beads were used to concentrate Cr(V1)prior to determination by electrothermal atomic absorption spectrophotometry (B23). The beads were directly injected into the atomizer for the determination of Cr. The detection limits for Cr(V1) and total Cr were 0.01 and 0.2 pg/L, respectively. Chromium(V1)was extracted from water samples using 0.1 mL of 1-pyrrolidinecarbodithioate at H 3.5 in 1,Zdichlorobenzene (B24). Chromium(II1) was sul!sequently oxidized by Ce(1V)and then extracted with the same reagents. The two forms of Cr were determined by electrothermal atomic absorption spectrophotometry in both seawater and river water samples. Chromium was adsorbed by a DTPA complex on a hanging Hg drop electrode and then determined using cathodic stripping voltammetry (B25).The detection limit was 5.0 ng of Cr/L and did not show interference from or anic ligands. The Cr(111)-4-(2pyridy1azo)resorcinol caelate was determined by reduction on a hanging H drop electrode (B26). The detection limit wasO.1 pg of Cr/k. Chromium(VI) was determined in seawater by adsorption voltammetry (B27). The Cr(V1)-cupferron complex in a NH4+-NH3 solution is the adsorbed complex. The method has a recovery of approximately 92% and a detection limit of 0.04 pg of Cr/L. Chemiluminescence was used for the simultaneous determination of Cr(II1) and Cr(V1) (B28). A cation exchange column was used for the separation and Cr(V1) was subsequently reduced by K2S03. The detection was by a luminolhydrogen peroxide chemiluminescencesystem. The detection limit was 0.5 pg of Cr/L and the luminescence was linear over a concentration ran e of 1-1000 pg of Cr/L. A method using Fe(CN)& luminol clemiluminescence was described (B29). The detection limit was 0.02 pg of Cr/L and the linear range was 0.1-1000 pg of Cr/L. Fluorometry was coupled with catalytic-kinetic oxidation of Rivanol by Cr(V1) as a method for determination of Cr(V1) (B30). The method gave a linear response for 1-200 pg of Cr(VI)/L. Ion chromato raphic techniques are described for the separation of C r h ) from wastewaters (B31). The methods are automatedto allow for rapid sample processing,compared with traditional methods. No data were given on detection limits and measures of variation. Another nonautomated ion chromatographic technique for Cr(V1) was described (B32). Details of the method were not given, but recoveries were a proximately 100% ,there was no appreciable oxidation of Cr(fI1) to Cr(VI), and the detection limit was 0.3 pg of Cr(VI)/L. A kinetic spectrophotometric method for Cr(II1) based on formation of a com lex between Cr(II1) and 442-pyridylazo)resorcinol was Bescribed (B33). The formation of the complex was monitored at 530 nm. The method has a high detection limit of 400 pg of Cr/L, but is suitable for wastewaters. Extraction of Cr(V1) with N-hydroxy-N,N’diphenylbenzamidine into chloroform prior to s ectrophotometric measurement was described (B34). The &enhances the color of N-4-ethylenediamine-3’-fluorobenzeneazonapthalene which is determined at 555 nm. The detection limit was 3 pg of Cr(VI)/L. Chromium(V1) reacts with lead acetate in an ethanol solution to form lead-chromate which coprecipitates Cr(V1) (B35). The precipitate is filtered through a 0.2 pm filter, and the filter analyzed by X-ray fluorescence spectrometry. The calibration was linear in the ran e of 50500 pg of Cr(V1) but could be reduced to 1pg of &(VI), if additional lead acetate was added as a carrier. A similar method using sodium dibenzyldithiocarbamate as the precipitating agent in an aqueous solution with trace methanol was described (B36). An X-ray fluorescence measurement of the Cr resulted in a detection limit of 0.7 pg of Cr(VI)/L. Most other cations did not result in interference, exce t for Ni, Zn, and Mn, which resulted in si al depression. 8hromium(II1) was separated from Cr($ in a two-step coprecipitation with pyrrolidine dithiocarbamate (B37). Coprecipitation at a pH of 4.0 removed Cr(VI). The pH was adjusted to 9.0 for the coprecipitation of Cr(II1). The two forms of Cr were determined by neutron activation analysis and testa on NIST reference material 1643b were in agreement with the certified value.
A Cr(II1) and Cr(V1) aqueous standard at total concentrations in the range of 25 pg/L were stabilized using a 50 mmol/L HC03--H&03 buffer in a PTFE container (B38). The standard was refrigerated under a carbon dioxide atmosphere. Manganese.A spectrophotometric method for the in-situ analysis of Mn in marine hydrothermal lumes was described was (B39). The complexing agent 1-(2-pyrifylazo)-2-napthol used in a submersible analyzer which was operated to depths of 3000 m. Iron interference was eliminated by chelation with desferrioxamine B. The detection limit was approximately 1.0 pg of Mn/L. Catalytic spectrophotometry using the oxidation of methyl red by KI04 in the presence of nitrilotriacetic acid was used for the determination of Mn (B40). The detection limit was 2.2 pg of Mn/L. Flow injection analysis coupled with stopped-flow catalytic spectro hotometry was used for the determination of Mn (B41). Magchite green is oxidized by KI04 in the presence of nitrilotriacetic acid. The detection limit was 0.07 pg of Mn/L. A similar method using the Mn(I1)-catalyzed reaction between fuchsin and KI04 in nitriloacetic acid was described (B42). Polarography was used to measure the fuchsin, which compared favorably with the spectrophotometer measurement. Manganese was determined by spectrophotometric flow injection analysis by the oxidation of N,N-dimethyl-p-phenylenediamine with m-phenylenediamine in the presence of HzOz (B43). The catalytic activity was enhanced by triethylenetetramine and 1,2-dihydroxybenzene-3,5-disulfonate.The detection limit was 0.05 pg/L, and the relative standard deviation was 3%. Manganese in seawater was concentrated on 8-hydroxyquinoline immobilized on a vinyl polymer gel (B44). The Mn is eluted with acid and determined by the reaction of leucomalachite green and KIOd with the Mn. The detection limit was 2 ng of Mn/L using a 15 mL sample. The precision was 5 % in the 20 ng of Mn/L concentration range. A similar method uses p-aminobenzenesulfonic acid with KI04, and NTA as arl accelerant (B45). The method was applied to the determination of Mn in the 0.4-8.0 pg of Mn/L range. The relative standard deviation was 2.6-3.2%, and the recovery was in the range of 87-102 % . Another author reported on the use of Acid Chrome Blue K with KI04 in a Britton-Robinson buffer solution at a pH of 11.92 for the determination of Mn by spectrophotometry (B46). The detection limit was 0.05 pg of Mn/L, and the range of application was 0.05-5.0 pg of Mn/L. A variation in the method of detection of the catalytic oxidation in the determination of Mn was reported (B47). The reaction is the catalysis by Mn of the oxidation of Tiron by H2Oz. The reaction was monitored by increase in temperature with time. The method could be applied to Mn in the range of 1-120 pg/L. Photooxidation of sulfite with Rose Bengal was applied to the determination of Mn (B48).The photosensitization was reported to be 10 times greater than chemical activation. Thedetection limit was 0.3 pg of Mn/L with a relative standard deviation of 5.5%. Fluorometry has also been applied to the measurement of the catalytic oxidation process (B49). Rhodamine 6G with KI04and NTA activator were used as reagents. The detection limit was 0.2 pg of Mn/L. A similar fluorometric method using fluorescein with KI04 and nitrilotriacetic acid as an accelerator was described (B50). The detection limit was 0.073 pg of Mn/L, and the linear range was 0.1-3.2 p of Mn/L. Chemiluminescence detection of Mn separated%y flow injection analysis was reported (B51).The Mn was concentrated on a column containing 8-hydroxyquinoline. The oxidation of 7,7,8,8tetracyanoquinodimethane under alkaline conditions produces the photons which are detected. Seawater samples were analyzed in 6 min with a detection limit of 5.5 ng of Mn/L. The method was tested using the NASS-1 and CASS-1 standards. Solvent extraction using sodium diethyldithiocarbamate, followed by extraction with diisobutyl ketone, was used to concentrate Mn (B52). The solution was analyzed by laserenhanced ionization spectrometry using the 279.5-nm emission line. The detection limit was 0.09 pg of Mn/L. Seawater samples were extracted with 8-quinolinol into chloroform and then into 7 M HNOs (B53). The Mn was determined by electrothermal atomic absorption spectrophotometry. A detection limit was not given, but the relative standard deviation was 6% at the 0.07 pg of Mn/L range. ANALYTICAL CHEMISTRY, VOL. 65,
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tadecyltriethylammonium bromide was described (B70).The Iron. Kinetic spectrophotometry was ap lied to the reaction was applied to the determination of Co in freshwaters determination of Fe in groundwaters (B54). he oxidation with a detection limit of 1 pg of Co/L. The oxidation of of Fe is accelerated by Tiron, which is measured a t 560 nm. p-aminobenzenesulfonic acid by H202 as catalyzed by Co was The method was described as not requiring precise control described as a method of determination (B71).A linear range of temperature. Flow injection analysis was coupled with of 0.01-500 p of Co/L and a detection limit of 0.01 pg of COIL spectrophotometry in emplo ing the catalytic effect of the was reportef. Flow injection analysis was coupled with Fe(II1)-EDTA complex on t i e oxidation of hydroxylamine chemiluminescence in a method for the determination of Co by dissolved oxygen (B55).A detection limit of 2.0 pg of (B72).A similar linear range and detection limit as described Fe/L and a linear response over the range of 3.5-150 pg of in ref B71 were obtained. The recoveries ranged from 98 to Fe/L were reported. Minor interferences by high concen102% with samples analyzed at a rate of 100/h. trations of Co, Cu, and Cr(III) were noted. Iron in seawater Flow injection, coupled with extraction, followed by elecwas determined by flow injection analysis and chemiluminescence detection (B56).The photon emission is by the trothermal atomic absorption spectrophotometry was used reaction of Brilliant Sulfo Flavin with H202 and Fe(I1) at for the determination of Co in seawater (B73). Sodium diethyldithiocarbamate was used to complex Co, and CUneutral pH. The detection limit was 25 ng of Fe/L with a bonded silicareversed-phasesorbent was used in the adsorbing relative standard deviation of 2-5% for samples >lo0 ng of Fe/L. A method where Fe(II1) forms an anionic chelate of column. The preconcentration possible is directly propor2,2‘-dihydroxyazobenzenewhich is reacted with crystal violet tional to the time and amount of sample processed. A 28-mL and then adsorbed on the surface of a PVC film was described sample concentrated over a 10-min loading time resulted in a detection limit of 1.7 ng of Co/L. The method was calibrated (B57).The plating of the blue-violet ion pair allows for detection of Fe(II1) a t a concentration of 0.6 pg of Fe/L at 592 using the NASS-1 standard at 4.0 ng of Co/L. Cobalt was preconcentrated with 1,2-cyclohexanediondioximeon actinm. Iron(I1) and Fe(II1) were chelated using di-2-pyridyl Test vated carbon in a method for Co in natural waters (B74). ketone benzoylhydrazone for subsequent determination by solutions containing 0.08-0.25 pg of Co were quantitatively spectrophotometry (B58).The chelated samples from cloud/ fok moisture are extracted into chloroform-water for deterextracted. The detection.limit was 14 ng of Co/L. Another mination at 370 or 660 nm. The detection limit was 0.2 pg method of preconcentrating Co from natural waters used Unicellex A-100, B-100, UR-30, and Ur-3300 resins (B75). of Fe/L. Iron was preconcentrated on an ion exchanger, eluted with acetate, mixed on-line with 4,7-diphenyl-l,lO-phenan- The eluate was analyzed for Co using electrothermal atomic throline disulfonate for determination by flow-throu h s ecabsorption spectrophotometry. A 10-mLsample was typically used, and the detection limit was 0.050 pg of Co/L. Relative trophotometry (B59).The colored Fe complex was aisorted standard deviations were 1.0% for 0.97 pg of Co/L in river in the flow-through cell by immobilized anion exchanger and the absorption continuously measured. The detection limit water and 4.5% for 0.22 pg of Co/L in seawater. was 0.1 p of Fe/L when the Fe from 80 mL of water was Adsorptive voltammetry was uaed for the determination integratet! in the cell. A PVC membrane containing 4,7of Co in natural waters (B76).The Co complex with 5-Brdiphenyl-1,lO-phenanthrolineand o-nitrophenyl octyl ether PAD” is adsorbed in the presence of O.O030% Triton X-100 was used to extract trace Fe from solution by immersion of and the polarographicwave measured at -0.90 V. The detection the membrane (B60).The red iron complex was directly limit was 6 ng of Co/L. measured on the sheet after a set equilibration time at 538 Nickel. Nickel was extracted from seawater by 5-nitronm. The method of collection is somewhat novel, but the salicylaldehyde-4-phenyl-3-thiosemicarbazone(NSPS) and detection limit was only 38 pg of Fe/L, An automated method determined by flame atomic absorption spectrophotometry for monitoring Fe in boiler water was described (B61).The (B77).The Ni-NSPS complex was extracted into methyl method uses the TPTZ spectrophotometric method. The isobutyl ketone and analyzed using an air-acetylene flame. method was used for the range of 0-200 pg of Fe/L with a 3 % The detection limit was 0.2 pg of Ni. Extraction of Ni with relative standard deviation. Iron determination in seawater dithiocarbamate into xylene and then back-extraction into using ferrozine was described (B62).Relatively large volumes HNQ3 was described (B78).The solution was analyzed by of seawater are passed through a CU Sep-Pak cartridge electrothermal atomic absorption spectrophotometry. The containin ferrozine. The Fe-ferrozine complex was eluted concentration factors can be as high as lOOO-fold, allowing with metfanol and the absorption measured a t 562 nm. the determinationof Ni a t nanogram per liter concentrations. Recoveries were estimated at 91% and the detection limit Adsorptive cathodic stripping voltammetry was applied to was 33 ng of Fe/L. the analysis of Ni using a 5-[ @-methypheny1)azol-&aminoDifferential pulse voltammetry with carbon paste electrodes quinoline complex with Ni (B79).The Ni is concentrated for modified with 2,2’-bi yridyl and Ndion were used for the 3 min, resulting in a detection limit of 1.8 ng of Ni/L. determination of Fe&) (B63).A 3-min accumulation time Copper. Solvent extraction of Cu with sodium diethgave a detection limit of 0.6 p of Fe/L. A similar method yldithiocarbamate followed by determination of the complex used 1,lO-phenanthroline and %&on for reconcentrating by spectrophotometry was described (B80).The complex Fe(I1) (B64).The method had a detection Emit of 0.56 pg of was separated from the aqueous phase in a phase separator Fe/L and a relative standard deviation of 4% in the lowand measured in a flow-throu h absorbance cell. The microgram per liter range. Cathodic stripping voltammetry detection limit was 0.05 pg of C u d , and the relative standard with adsorptive collection of Fe from seawater samples on deviation was 0.83% at the 4 pg of Cu/L level. Co per was 1-nitroso-2-naphthol was described (B65).The Fe is catacollected on a membrane filter as the N,N-diethyldkhiocarlytically reoxidized with H202. A detection limit of 0.009 p bamate complex (B81).The filter was dissolved in N,Nof Fe/L was claimed for. an accumulation time of 60 s. dimethylformamide for measurement by s ectrophotometry. similar method used 1-fiitroso-2-naphthol on a Hg drop Linear absorbance from 0.1 to 8.8 pg of 8u/L was observed electrode for the determination of Fe(II1) (B66).A detection with a relative standard deviation of 4.3% at the 1.2 pg of limit of 0.01 pg of Fe/L was determined, though the optimum Cu/L level. Kinetic oxidation by Cu of a variety of wateroperating range was in the 1 pg of Fe/L range. soluble thiols, including cysteamine, L-cysteine, 2-mercapCobalt. The oxidation of Tiron by H202y.a~catalyzed by toethanol, and 2-mercaptopropionic acid, was evaluated in Coat a pH of 10.5 in a phosphate buffer (B67).The absorption .several solvents (B82).The oxidation of the thiols by the Cu was continuously measured for the 2-3-min reaction time at was best in N,N-dimethylformamide, and the rate of oxidation 440 nm. The detection limit cited was 0.004 $g of Co/L. Cobalt was monitored by spectrophotometry. The detection limit catalyzes the oxidation of aminobenbnesulfonic acid by H202 was 2.5 pg of Cu/L, and the relative standard deviation was (B68). The absorption is measured at 320 nm and the 1.8%at a Cu concentration of 10 pg of Cu/L. Flow injection detection limit was 0.02 pg of Co/L. analysis was coupled with solvent extraction in a spectrophotometric method (B83).Several dihalogens were used Chemiluminescence has been applied to the determination for the extraction, and 4- [4-(diethylamino)phenylazol-Nof Co in natural waters (B69).The luminescent agent in this alkylpyridinium was used as the countercation. Thirty application was uercetin-KOH-H202. The detection limit samples per hour could be processed a t a detection limit of was 0.2 pg of COR,and the chemiluminescence intensity was 1.3 pg of Cu/L. The oxidation of eosine by HzOz is catalyzed linear in the range of 0.26-6.4 pg of Co/L. Another chemiby Cu, which is monitored by spectrophotometry at 515 nm luminescence method using the reaction of 4-diethyl(B84).Recoveries were in the range of 89-95% ,the detection aminophthalohydrazide and oxygen in the presence of pen-
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ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
WATER ANALYSIS
limit was 0.1 pg of Cu/L, and the calibration curve was linear in the ran e of 0.2-20 pg of Cu/L. Cop er in seawater was determine by the complexation of Cu y 1,lO-phenanthroline, followed by measurement of chemiluminescence during oxidation by Hz02(B85). The Cu was separated from seawater by extraction onto a column with immobilized 8-hydroxyquinoline. The processing time was only 8 min, with a detection limit of 25 ng/L. Copper was complexed with N,N-diethyldithiocarbamate and collected on a membrane filter (B86). The filter was dissolved in N,N-dimethylformamide, and the Cu was determined by electrothermal atomic absorption spectrophotometry. No specific information on the erformance was given, but detection at the microgram of u per liter level was claimed. Ultraviolet photolysis was used to decompose Cu-organic complexes prior to concentration of the Cu on an in-line Chelex-100exchange column (B87).This system was operated in-line with an atomic absorption spectrophotometer operating in the flame mode. The digestion system was demonstrated for several model Cu-chelate complexes. Coper was adsorbed from waters by xanthate cotton, followed gy acid desorption, and flame atomic absorption determination (B88).The method was compared with ICP-AES and polarography, with a useful application in the 3-200 pg of Cu/L range. The com lexation of Cu by or anic ligands in seawater was studied y Zeeman atomic a sorption spectrophotometry (B89). Interference was found to be reduced in the presence of tartaric acid, and the detection limits in seawater were decreased to 0.18 pg of Cu/L. Flow injection-solvent extraction with inductive1 coupled plasma atomic emission spectrometry was u s e i for the measurement of Cu in water samples (B90).The Cu was extracted with dithizone-CC14. The method was calibrated with NIST reference sample 1643a and demonstrated a detection limit of 0.1 pg of Cu/L and a relative standard deviation of 2.5 5%. The determination of Cu by pulse and stri ping voltammetric methods in the presence of natur a r ligands was described (B91). Significant interference by C1- and NH3 was found. Adsorptive voltammetry was used for the determination of copper in natural waters (B92). The Cu was accumulated on a graphite paste electrode by complexation with benzoin oxime. A 5-min accumulation time resulted in a detection limit of 1pg of Cu/L, with a linear range of 2-4000 pg of Cu/L and a relative standard deviation of 5 5%. Amperometric titration was used for the determination of the rates of formation of Cu complexes with OHand COS%(B93). The formation of these complexes was used to assess the potential for use of electrochemical measurements in the determination of total Cu. Copper was adsorbed by 2,2'-biquinoline on an activated carbon electrode, prior to determination by differential pulse polarography (2394). The adsorbed Cu complexis oxidized by acetonitrile and perchloric acid for measurement. The detection limit was 0.33 pg of CU/L. A solid-state copper ion-selective electrode was used for the determination of Cu activity in high C1- solutions (B95). The method was used for the monitorin of Cu activity in biological experiments in a seawater mefium. Multiple First TransitionSeriesMetals. High-pressure liquid chromatography was used for the determination of Cu and Co complexes of 2-(2-thiazolylazo)-5-(dimethylamino)benzoic acid-Triton X-100 (B96).The separation was made using 10 pm of YWG-CN on a 4.6 X 200 mm column with methanol-water and NOAc-NaOAc buffer. The detection limits were 1.7 pg of Cu/L and 1.3 pg of Co/L, with a linear response up to 160 pg of Cu or Co/L. HPLC was also used for the separation and determination of V(V), Cr(III), and Fe(II1) by chelation with 2-(2-thienylazo)-5-(diethylamino)phenol (B97). A Cu-bonded stationary phase was used with methanol-tetrahydrofuran-water and acetate buffer as the mobile phase. The interferences of Mg, Cd, Zn, Pb, Mn, Ca, Ba, Sn, W, Th, Fe(II),Bi, Zr, Ga, andLa were investigated. The detection limits were 0.5 pg of V(V)/L, 2 pg of Cr(III)/L, and 1 pg of Fe(III)/L. Copper and Zn were extracted into Mn-ammonium pyrrolidinedithiocarbamate (APDC) and determined by flame atomic absorption spectrophotometry (B98). Recoveries in the range of 90-967% were found for Cu and 86-105% for Zn. Extraction of Cu, Cd, Mn, Co, Pb, Ni, and Fe by APDC was
8
g
e
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E
a plied to the anal sis of natural waters (B99). The metal cgelates were adsorted on Amberlite XAD-4for preconcentration and subsequently determined by flame atomic absorption spectrophotometry. Diethyldithiocarbamate was used for the extraction of Cu(I1) and Fe(II1) associated with humic substances in natural waters (BI00). The extraction was found to be complete for Cu, but not for Fe(II1). The authors suggested the Fe(II1) existed as a hydrous iron(II1) oxide that was partially covered with the insoluble humic substances. APDC was found more effective in the recovery of Fe(II1). Preconcentration of Cd, Cu, Fe, Mn, Ni, and Zn by 8-hydroxyquinoline on Amberlite XAD-2 was used prior to the determination by ICP-AES (BIOI). The method was capable of preconcentration by a factor of 100, allowing measurement of the metals in Antarctic seawater. A review on the determination of Co and Ni in environmental samples was provided (BI02). Expected concentration levels, sampling and sampling preparation, preconcentration and separation, analytical methods, speciation, standardization, and quality control are discussed. Zinc. See section on Group 12 Metals. Second Series. Molybdenum. Molybdenum was determined in seawater b extraction with a-benzoin oxime in CHCla and ascorbic acid;BI03). The solution was evaporated to remove CHCl3 and extracted into (dimethylamino)phenylfluorone and cetyltrimethylammonium bromide and measured by flame atomic absorption spectrometry at 527 nm. The method was applied to waters in the range of 0-600 pg of Mo/L, and the potential interferences of a large number of trace elements were evaluated. Molybdenum in seawater was coprecipitated with Fe and diethyldithiocarbamate solutions at pH 3 (B104). The samples were measured by electrothermal atomic absorption spectrometry with a detection limit of 0.5 pg of Mo/L. Samples in the range of 2-20 pg of Mo/L gave a linear calibration curve, and the relative standard deviation was 2.3%. Coprecipitation of Mo with Co and diethyldithiocarbamate from freshwater and seawater samples was described (BI05). The precipitate was dissolved in HN03 and determined by ICP-AES. The detection limit was 0.52 pg of Mo/L and the method was calibrated using standard reference materials for seawater. Ion association by Rhodamine B and thiocyanate was used to complex Mo (BI06). The Mo(V1) was reduced to MOW) by thiocyanate, which is catalyzed by V(V). The Mo was determined by absorption spectrophotometry at 588 nm. The method was described as suitable in the range of 0-3 pg of Mo/L. A fluorescence quenching method for the determination of Mo was described (BlO7). The fluorescence is generated by the reaction of Mo(V)-SCN--Rhodamine B and poly(viny1alcohol). The detection limit was 0.12 pg of Mo/L. A similar method of fluorescence quenching was described (B108). The fluorescence of 4,7-diphenyl-l,lO-phenanthrolinedisulfonate complexed with Mo is determined by excitation a t 288 nm and detection a t 444.8 nm. Interferences by other aqueous constituents were found minimal and the method was suitable in the range of 0.01-1.0 mg of Mo/L. Differential pulse polarography and adsorptive stripping voltammetry were applied to the determination of Mo in waters (BI09). Molybdenum(V1)reacts with chloranilic acid which is adsorbed onto a hanging Hg drop electrode at -0.20 V. The Mo is stripped a t -0.62 V and had a detection limit of 0.02 pg/L with a 5-min deposition time. The relative standard deviation was 6.6% for Mo in the 0.1 pg/L range. Molybdenum was collected as a complex with 3-methoxy4-hydroxymandelic acid in an adsorptive stripping voltammetric technique (B110). A 2-min preconcentration gave a detection limit of 0.4 pg of Mo/L and a relative standard deviation of 3.7 5%. Differential pulse voltammetry for determination of Mo(V1) in a nitrate medium was described (Blll). The method was improved by the addition of 8-hydroxyquinoline for a detection limit of 0.67 pg of Mo/L. Some interference was noted by Cr(VI), Cu(II), and Pb(I1). A similar method was described using oxalic acid and Toluidine Blue (BI12). The resulting Mo(V) is concentrated on a hanging Hg drop electrode. The detection limit was 9.6 ng of Mo/L for a 4-min adsorption time. Interferences were noted for Sn(IV), Cu(II), Ag(I), and Au(II1). Tungsten.Tungsten was preconcentrated using sulfhydryl cotton, followed by chemiluminescence determination using ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
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aHzOz-W(V1)-I--1uminolsystem(B113).The detection limit was 0.03 pg/L, and a linear response range of 0.1-1000 r g of W/L with a relative standard deviation of 1.3-6.8% was reported. A variation of the chemiluminescence determination was described by the same authors (B114).This method had a detection limit of 0.084 pg of W/L and a linear range of 0.1-10 000 pg of W/L. Technetium. See section on Other Radionuclides. Palladium. See section on Precious Metals. Silver. See section on Precious Metals. Cadmium. See section on Group 12 Metals. Precious Metals. Silver. Silver was coprecipitated from seawater with Hg(I1) sulfide and the solid separated on a 0.45- pm membrane filter and redissolved with sulfuric and nitric acids (B115).The Ag was determined by electrothermal atomic absorption spectrophotometry. A detection limit was not given, but Ag in the 0.3 pg/L range was determined. A chemiluminescent method for Ag was described (B116). Under basic conditions, 9,lO-dimethylacridinium fluorosulfonate and KzSzOs in the presence of 2,2’-bipyridine undergo chemiluminescence, and the chemiluminescence is enhanced by Ag(1). The method has a detection limit of 0.86 pg of Ag/L and a relative standard deviation of 6.5% at the 8.6 pg of Ag/L level. Adsorption voltammmetry was used for the determination of Ag in wastewaters (B117).The Ag catalyzes the oxidation of NazSzOB with Safarin T. The detection limit was 2 pg of Ag/L, and the useful range was 4-160 pg of Ag/L. Gold. A N263-modified silica column was used for the preconcentration of Au, which was subsequently eluted with a thiourea-HC1 solution (B118).The Au was then determined by atomic absor tion spectrophotometry. Cetylpyridine bromide was usefto preconcentrate Au and Ag, which was subse uently extracted into MIBK (B119).The Au and Ag were jetermined by flame atomic absorption spectrophotometr with detection limits of 1.0 pg of Au/L and 0.2 pg of Ag/L. Jold was preconcentrated from wastewaters by reaction between AuCld- and Crystal Violet, which was extracted into toluene (B120).The Au complex was determined by spectrophotometry with a detection limit of 50 pg of AuIL. Recoveries ranged from 97 to 109% . Gold was extracted from wastewater samples by the use of tributyl phosphate (B121). Both neutron activation analysis (NAA) and X-ray fluorescence spectrometry were used for the determination of Au in the range of 2-20 000 pg of Au/L. The Au was converted to chloride species in a secondary concentration step using Clz, which allowed a NAA detection limit of 0.2 ng of Au/L. Preconcentration of Au on a trioctylphosphine oxide-coated tungsten wire was described (B122).The W wire is placed in a raphite cup for the electrothermal atomization of Au and tfetermination by atomic absorption spectrophotometry. The detection limit was 0.2 pg of Au/L. Gold was also preconcentrated on a trioctylphosphine oxide-coated glassy carbon electrode (BI23).Strippin voltammetry was used for measurement of Au(II1). The ktection limit was 0.6 pg of Au/L, and there was a linear response in the range of 1.0-20 pg of Au/L. Palladium. Liquid chromatography was the basis of several preconcentration methods for Pd. A quaternary ammonium salt-N263-silica gel was used to preconcentrate Pd, prior to The analysisby atomic absorption spectrophotometry (B124). same authors used N1923-silica gel to preconcentrate Pd, with subsequent elution with thiourea (B125).Another trialkylamine- (N235-) modified silica gel was used for the separation of Pd as well as other noble metals (B126). Palladium was preconcentrated into a 1-phenyl-3-methyl4-benzoyl-5-pyrazolonatecomplex, which was subsequently extracted into MIBK (B127).The Pd was determined by flame atomic absorption with a detection limit of 30 pg Pd/L. A stripping voltammetry method was used for the the determination of Pd ( B I B ) . The Pd is reacted with dimethyllyoximein the presence of sodium dodecylbenzenesulfonate. he detection limit was 4 pg of Pd/L. Other Platinum Group Metals. A silica gel resin containing aminoguanidine was used for the simultaneous preconcentration of Au, Pd, Rh, and Ir (B129).Analytical methods were not discussed, but recoveries were in the range of 73-111%. Trialkylphosphine oxide was used for the extraction of Ir (B130).The Ir was subsequently determined by anodic stripping voltammetry. The potential for the development of a field-based method of measurement of Pt
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was described (B131).A platinum-formazone complex is formed on a Hg drop electrode in a hydrazine-formaldehydesulfuric acid medium. The results were compared with ICPMS measurements, and matrix effects were found to be severe. Lanthanides (Rare-Earth Elements). Nine rare earth elements were determined in thermal springs by copreci itation with A1 (B132).The preci itate was irradiatedy!l thermal neutrons and La, Ce, Nd, t m , Eu, Tb, Tm, Yb, and Lu were determined in the 0.3-50 ng/L range. A similar procedure was used for the determination of Pr, Nd, and Er (B133).The use of standard additions indicated there were errors in the range of 7-56 % . Inductively coupled plasma mass spectrometry (ICP-MS) was used for the direct determination of the rare earths and U and Th in freshwaters (B134).The detection limits of the elements were in the range of 0.5-11.6 pg/L, except for Sc, which was 92 pg/L. Another author used ICP-MS for the direct detection of rare-earth and actinide elements in waters but did not describe the results (B135).Preconcentration with bis(2-ethylhexyl) hydrogen phosphate and 2-ethylhexyl dihydrogen phosphate in heptane was used for the rare earths (B136).The extract was back-extracted into octanol and nitric acid. Subsequent determination of the rare earths by ICPMS demonstrated an improvement in sensitivity and a reduction of matrix effects. The rare earths, plus U and Th, were coprecipitated from freshwaters with Fe(0H)s (B137). The recoverieswere approximately 100% ,though the relative standard deviations ranged from 66 to 127% A similar coprecipitation method with Fe(OH13 was described ( B I B ) . ICP-MS determination of the rare earths, and T h and U, gave detection limits of 2.3 pg of Y/L, 1.4 pg of La/L, 5.6 pg of Nd/L, 0.8 pg of TWL, 1.0 g of TWL, and 0.7 p of U/L. Rare earths were determinefin seawater by ICP-hS after extraction, followed by back-extraction (B139).The extracting reagents were not described, but the method was claimed to have reduced matrix effects to negligible levels. The precision for the method including the extraction and backextraction steps was 90% were determined in the range of 10-500 pg of Cd/L. The Cd was determined by either neutron activation analysis or atomic absorption spectrophotomet A variety of matrix modifiers for the determination of E d in seawater were evaluated (C18). The best modifier was tartaric acid and HN03, and Cd was determined by Zeeman atomic absorption spectrophotometry. Specific performance data were not given, but the method was evaluated using seawaterstandards. Another author determined that oxalic acid was effective as a matrix modifier for the determination of Cd in seawater by Zeeman atomic absorption spectrophotometry (C19).The detection limit was 3 ng of Cd/L. Cadmium was preconcentrated on a mercury film electrode a t -1.0 V for a 120-5 period, followed by determination by flame atomic absorption spectrophotomet (C20). The detection limit was 0.92 pg of Cd/L, and the r z t i v e standard deviation was 5.3% at the 30 ng/L level. Adsorptivestrip ing voltammetry was used to determine Cd in wastewater (&I). The Cd was adsorbed as a complex with 7-[(4-chloro-2nitrophenyl)azo]-8-hydroxy-quinoline-5-sulfonic acid. The detection limit was 0.20 pg of Cd/L with a linear response ran e from 2 to 90 pg of Cd/L. The method comparedfavorably w i d atomic absorption spectrophotometry. Cadmium was collected on a carbon paste electrode modified with Amberlite IRC 178 chelating resin ((722).The Cd was collected for 10 min in a 0.001 M ammonium buffer at pH 9.0. The detection limit was 5 pg of Cd/L. Differential pulse polarography was used for the measurement of Cd (C23).Sodium perchlorate with Triton XlOO was used as the support electrolyte. Recoveries were in the range of 97-985% for fresh- and seawater, though no detection limit was given. Two reviews on the determination of Cd in biological and environmental materials were noted (C24,C25). Both papers discuss sampling and preconcentration, analytical methods, quality control, and reference materials. Mercury. A moderately large number of methods involve the cold vapor atomic absorption spectrometric determination of Hg. The decompositionof organic and inorganiccomplexes of Hg is critical to the complete recovery for determination. Several papers discuss the decomposition techniques specifically. The suppression of the Hg si nal in cold vapor atomic absorption spectrophotometryby ioiine was discussed (C26). The Hg evolved during heating is passed through a solution of 1M NaOH containing 15 mg of Cu(II)/L and 0.2% SnClz. Organic-Hg interferences were removed by digestion in HCl
.
or HN03in the resence of Br03- or B r at room temperature (C27).The mettod was considered superior to digestion with H2S04-KMn04. Decom osition of organic-Hg compounds using the combination of &(,I) and Sn(I1)in alkaline solution was described (C28).This was combined into a continuous flow analysis (CFA) system and a flow injection analysis (FIA) system for sample and reagent control. The detection limit was 0.08 p of Hg/L for the CFA system and 0.5 pg of Hg/L for the FfA system. Organic mercury compounds were decomposed by K2S2Os with FeCl3 as a catalyst (C29).The Hg was reduced by Sn(I1) under alkaline conditions. 0x1dation of organic-Hg compounds by sonication was described (C30,C31). One pa er described the use of ultrasound at a frequency of 18-24 k h z and an intensity of 12-20W/cmz. The H was then preconcentrated with a dithizone solution into C&P rior to determination by cold vapor atomic absorption spectro hotometry. The detection limit was 0.004 pg of Hg/ L. Oxi&tion of organicHg compounds with KMnO4 in a HzSO4-HN03 mixture at 105 "C was described (C32).After digestion, the solution was cooled prior to reduction with hyroxylamine hydrochloride and Sn(I1). Recoverieswere in the 92-106% range. Reduction of Hg by sodium borohydride in a solution containing HC1 and ethanol was described (C33). The detection limit was 0.013 pg of Hg/L, the relative standard deviation was 0.65%, and recoveries were in the 97.103% range. A continuous sampling and analysis system was developed for the monitorin of Hg in wastewaters (C34). The samples are digested, recfuced, and extracted in 0.5-mm tubing, prior to determination by cold vapor atomic absorption s ectrophotometry. Samplin intervals were 3 min, with a etection limit of 0.15 pg of /L and a relative standard deviation of 1%at the 4.0 p o Hg/L level. Electrothermal atomic absorption s ectrop%otometryhas been applied to the determination ofHg in waters (C35,C36). A number of matrix modifiers were tested, of which TeO2 in HC1 was determined to be best (C35).A 50-pL sample was atomized a t 1750 OC. The detection limit was 0.39 pg of Hg/L, and recoveries were 97-100% for NIST SRM 1641b. Electrothermal atomization of Hg and determination by a Zeeman atomic absorption spectrometer was described (C36).The aqueous Hg was extracted into chloroformfor determination. A detection limit of 0.8 ng of Hg/L was claimed. Cold vapor atomic fluorescence determination of H in waters has been described (C37).The Hg was adsorbef on xanthate cotton, desorbed with a HC1-NaCl solution and reduced by NaBfi. The relative standard deviation was 3.1 5% a t the 0.5 pg of Hg/L range. Fluorometry has also been used for the determination of Hg (C38).Mercury(I1) reacts with Br and fluorescein to form an ion pair which is extracted with n-butyl acetate. The fluorescence is excited at 452 nm and measured at 476 nm, with a detection limit of 0.4 pg of Hg/L. The reaction between tetraiodomercurate(I1) and the triphenylmethane cations, Brilliant Green, Malachite Green, and Crystal Violet was investigated as a means of fluorometric determination for Hg (C39). All three dyes were suitable, and the complexes were excited a t 256 nm and measured a t 521 nm. The detection limit was 0.72 pg of Hg/L. Several miscellaneous methods were used for the determination of H Anodic stripping voltammetry with a goldplated electrde was used for the determination of Hg and As (C40).The detection limits for both elements was in the microgram per liter range. Mercury was preconcentrated by coprecipitation with copper sulfide and analyzed by neutron activation analysis (C41).The lWHgisotope was counted by 7 spectroscopy. No detection limits were given, but the method was applied to water samples in the 0.065-0.07 pg of Hg/L range. Inductive1 coupled plasma mass spectrometry was applied to the anJysis of Hg (C42).The use of direct injection nebulization was found superior to the pneumatic nebulizer. Specificperformance data were not given, but the method was compared with cold vapor atomic absorption s ectrophotometry. A novel immunoassay method for the &termination of Hg was described (C43).The assay utilizes a monoclonal antibody which binds Hg(I1). The absorbance is measured to determine Hg in the range of 0.5-10 pg of Hg/L and was found comparable in performance to cold vapor atomic absorption spectrophotometry. Multiple Group 12 Metals. Several metals, includin Cd, Cu, Pb, and Zn were concentrated from snow-derivefi
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waters on tungsten wires, prior to determination by electrothermal atomic absorption spectro hotometry (C44). The detection limits were 0.01 n of Cd/ig, 0.47 ng of Culkg, 0.22 ng of Pb/kg, and 0.24 ng of n/kg, allowing determination of these metals in both modern and ancient polar snows. Group 13 Elements. Aluminum. Aluminum exhibits a tendency to form a colloidal-sized particulate in natural waters. The particle size range of Al-containing particulate Filters with nominal sizes of 0.45, was investigated (01). 0.22,0.05, and 0.025 pm were investi ated. Filtration through a 0.025-pm filter was required to efectively remove A1 from solution. A portable, automated method of monitoring A1 in surface waters was described (02). Flow injection analysis is used to mix the sample with pyrocatechol violet, which forms colloidal particulates that are measured by spectrophotometry at 580 nm. Iron interference is reduced by reduction to Fe(I1) and complexation with 1,lO-phenanthroline. The system is ca able of automatically determinin A1 on a 30-min cycle. Plow injection analysis was usef to determine speciation of A1 in natural waters (03).Aluminum hydrox species are determined by the rate of reaction with oxine. $he residual oxine and the Al-trioxinate complex are extracted into chloroform, and the residual oxine is determined by spectrophotometry. The method can determine A1 speciation in aqueous systems with at least 5 pg of Al/L. Fluorometry is the basis of several methods for determinin Al. A fluorescent Al(II1)-Eriochrome Red B complex was usei for the determination of A1 (04).The detection limit was 0.1 pg of AUL. Several fluorescent reagents were evaluated for the determination of Al, including Acid Chrome Dark Blue, Eriochrome Blue SE, Acid Chrome Blue K, and Chromazol KS (05). The detection limits when using these reagents varied from 0.045 to 1.0 pg of Al/L. Solochrome Violet RS was used for the determination of Al, with a detection limit of 0.02 pg of Al/L (06). A1 complexation with 8-hydroxyquinoline-5-sulfonic acid was used for the fluorometric The interference by Fe required determination of A1 (07). a correction and the detection limit was 1.0 pg of Al/L. The formation of an A1 com lex with 2,6-bis[(o-hydroxyphen y1)iminomethyll-1-hyiroxybenzenein ethanol was used for the spectrofluorometric determination of Al (08). The detection limit was 0.1 pg of Al/L with a relative standard deviationof 1.5% intherangeof 1-10pgofAVL.Flowinjection analysis and spectrofluorometric determination of Al was described (09).The Al(II1) complex with Eriochrome Red Bin the presence of hexamethylenetetramine or acetate buffer was determined. The detection limit was 0.3 pg of Al/L and the relative standard deviation was 2.5 % a t the 20 pg of Al/L level. Aluminum was complexed with 5,7-dibromo-8-quinolinol in a spectrofluorometric flow injection analysis system (010).The complex was extracted into diethyl ether with excitation at 400 nm and determination at 525 nm. The detection limits were 0.3 pg of Al/L for the on-line determination, and the coefficient of variation was 3% at the 4 pg of Al/L level. A variety of other methods was used for the determination of Al. Liquid chromatography was used to separate the hydroxy species of A1 from the fluoro and organic species (011). The method was used to investigate the changes in Al speciation during treatment of potable waters. Aluminum was chelated with 2,2'-dihydroxyazobenzene, which was determined by high- erformance liquid chromatography (012). The detection Emit was 1.0 pg of Al/L, and recoveries were in the range of 98-104%. Aluminum was preconcentrated by immobilized 8-hydroxyquinoline for 3 min prior to determination by flame atomic absorption spectrophotometry (013). The Al-complex was eluted with HC1-HN03 *and analyzed in an NzO-acetylene flame. The detection limit was 3 pg of Al/L. Electrothermal atomic absorption spectrophotometry was used for the determination of Al in natural waters (014).A matrix modifier of Pd-Mg(NO& was used. Aluminum was preconcentrated from natural waters on a PTFE membrane filter with benzyldimethyltetradecylammonium ion (015). The complex was eluted with ethanol and N,N-dimeth lformamide and determined by electrothermal atomic agsorption spectrophotometry. Solvent extraction with acetylacetone or 8-hydroxyquinoline in 4-methylpentan-&one was used for the preconcentration of A1 (016).The Al complex was determined by atomic absorption spectrophotometry in an NzO-acetylene flame. The detection
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limit was 5-1Opg of AVL, de ending on the complexingligand used. The A1 content of &e-particulate slurry was determined directly by electrothermal atomic absorption specDetails of the procedure were not trophotometry (017). described. Voltammetry was used for the determination of A1 as the pyrocatechol violet (PCV) complex (D18).The complex is adsorbed on a H drop electrode, which gave a current peak a t -0.90 V for refuction of the A1-PCV complex. The detection limit was 0.1 pg of Al/L. Gallium. Fluorometry was used for the determination of Ga (019).The GaCL ion is formed, complexed with butyl Rhodamine B, and then extracted into benzene. The complex is excited at 550 nm and measured a t 560 nm. The detection limit was 2 pg of Ga/L in the organic phase. Gallium was preconcentrated on a film of trioctylphosphine oxide on a tungsten wire electrode at 0.3 V (020).The electrode is heated in a graphite cup and the Ga determined by electrothermal atomic absorption spectrophotometry. The detection limit was 10 ng of Ga/L, and the relative standard deviation was 5.5% for Ga in the 2 pg/L range. Both Ga and In were determined by a kinetic method (021). The method is based on the change in absorbance during the displacement of the metallochromicligand PAR by acid. The method was claimed to have a detection limit of 0.2 mg/L for each metal, though this is far higher than the concentrations expected in natural waters. Indium. See ref D21 in the section on gallium. Group 14 Elements. Tin. The Sn(1V)-catechol complex was adsorbed on a Hg drop electrode in the voltammetric determination of Sn (El). The detection limit was 5 ng of Sn/L, and the relative standard deviation was 2.2 7% at the 50 ng of Sn/L level. A s ectro hotometric method for Sn in Tin(1V) was extracted with wastewaters was descrged B r into a chloroform solution of N,N'-di henylbenzamidine and subsequently treated with iodine. !'he absorptivity of the iodostannate complex was determined, and the detection limit was 0.1 mg of Sn/L. Lead. Electrothermal atomization was used for the determination of Pb in seawater by atomic absorption spectrophotometry (E3). The P b was co recipitated with Hg on pyrolytic graphite platforms. The ietection limit was 0.15 pg of Pb/L, and the relative standard deviation was 88%.
Trace metals were coprecipitated with Fe-dieth ldithiocarbamate for determination by inductively couplei plasma atomic emission spectrometry (ICP-AES) (J19). The recoveries were in the ran e of 88.106% for Ni, Co, Cr, V, Cu, Pb, Zn, Mn, and Cd, and the detection limits were in the range of 0.01-5 p /L. A column was used for the concentration of trace meta!s from seawater (J20). Amberlite XAD-2 resin with either 8-hyroxyquinolineor 1-(2-thiazolylaz0)-2-naphthol was used for the preconcentation. The eluate was subsequently analyzed by ICP-AES. Adsor tion of Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn, and Y from seawater! diethylenetriaminetetraacetate on fibrous cellulose was iescribed (J21). The metals were eluted with strong acid and determined by ICPAES. The detection limit ranged from 0.1 to 3 pg/L. The use of the inductively coupled lasma mass spectrometer (ICPMS) for leachates from t f e toxic characteristic leaching procedure (TCLP) was described (J22). The performance of this analytical method was evaluated in terms of recoveries and cam arison with ICP-AES analysis of Ba, Cd, Pb, Se, Zn, Cr, and 8u. ICP-MS was used for the analysis of freshwaters and colloidal-sized particulates suspended in these waters (J23). Evaporative concentration was used with ICP-MS for the determination of a large number of trace metals in ultrapure water in the ppt range (J24). The modification of the nebulizer to incorporate a gas-liquid separator was described (J25). This ap aratus allows the introduction of metal hydrides into an I&-AES or ICP-MS system, taking advantage of the sensitivity of the instrument, and the preconcentration effect of the hydride method for As, Sb, Se, Te, Sn, and Bi. The European Community is developing a series of aqueous reference materials for calibration use (J26). This research described the use of ICP-MS techniques in the evaluation of these proposed reference materials. A round robin study of several types of environmental samples, includin freshwater, was described (J27). ICP-MS, ICPAES, ETAAS determinations were compared in this study for a lar e number of elements over a large concentration range. $hose analytes at the lowest concentration ranges showed the poorest comparability. Lead and cadmium in polar snows and ice cores were determined by laser-excited atomic fluorescencespectrometry (LEAFS) (528).The method allows for the direct determination of these elements a t 5 pg of OdL (L16). Dissolved 0 was determined by a chronoamperometric method usin a C disk microelectrode (L17).A graphite-reinforced electrode (pencil lead) was used in determining Os in water by amperometry. The linear range was 10-250pM O3 (L18). A glassy C electrode modified with cobalt tetraphenylporphyrin was used in determining DO by differential pulse voltammetry (L19). Chlorine and Chlorine Oxides. Free C1 in water was determined spectrophotometrically after reaction with p amino-N,N-diethylaniline.Beer’s law was obeyed for 0-100 pg of C1/50 mL at 553 nm (L20). Residual free C1 was determined spectrophotometrically in the resence of other chlorine species by usin Acid Yellow 17. TEe detection limit was 50 ng of Cl/mL $21). A method was described for determining Cl02 s ectrophotometrically. The detection limit was 0.03 p m 8102 using Lissamine Green B (L22).A FIA method for Betermining free and combined C1usingN,Ndiethyl-p- phenylenediamine was reported which gave a linear response in the range of 0.1-8.0 mg of C12/L (L23). A FIA method for determining free C1 in the presence of other C1
fiE
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WATER ANALYSIS
s cies was presented. Free C1 was reacted with 4-nitrop enylhydrazine and N-(1-naphthy1)ethylenediaminedihydrochloride and detected by measuring the absorbance at 532 nm. The detection limit of this method was 0.03 pq of Cl/mL (L24). Three procedures for indirectly determining C1 in water based on the induced I-azide reaction were reported (L25).Chlorine dioxide was determined fluorophotometrically based on quenching the fluorescence of chromotropic acid. The linear range was 0.55 pb to 1.4 pm ClOz (L26). Free chlorine in water was &terminel by acidifying the sample, purging it with N, and measuring the C1 in the N stream with a Au porous electrode (L21). An o toelectrochemicalsensor employing an electrochromicthinsensing layer on a lanar wave guide was developed for measuring dissolved 1 (L28). An indirect method for determining C1 was reported which was based on removal of electrochemicallydeposited Cu from a gold electrode (L29). Chlorine and monochloramine were determined on the basis of direct reduction rates by I- a t a pulsed AgI electrode (L30). Chlorine dioxide was removed from water using a glass tube separator and determined by a thin-film semiconductor. The method uses no reagents and had a detection limit of 23 ppb ClOz (L31). An amperometric cell was used to continuously measure ClOz in water in the range of 5-500 pg of ClOdL
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(L32). Other Gases. Hydrogen was separated from water by a hydrogen-permeable membrane and measured by a metal oxide semiconductor sensor (L33). Oxy en, nitrogen, and hydrogen were stri ped from water wit‘i; He (with N for determining H) anxmeasured by gas chromatography with thermal conductivit detection (L34). Headspace gas chromatography was useitodetermhe 0 and N in seawater (L35). Nitrous oxide was determined in natural water by headspace as chromatography with electron capture detection 6536). %ibero tic sensors for measuring dissolved COz were develo ed ( k 7 , L38). Direct potentiometry using ion-selective etctrodes was used to determine COz and NH3 in water (L39). A method to calibrate a pHzS electrode cell using silver ion buffers was presented (L40). Reduced S gases were preconcentrated onto a Tenax trap and determined by gas chromatography with flame photometric detection (L41). A Pt electrode was used to determine the end point in a method for measuringdissolved HZS by titration with Fe(CN)8 (L42). Development of a potentiometric HzS sensing system for continuously monitoring S” concentrations in water was reported (L43). A headspace gas chromatography method for determining CSZ in wastewater was reported (L44). A spectrophotometric method for determining CSZin wastewater was described with a detection limit of 0.1 mg of CSdL (L45).A procedure for extractin UKr from groundwater and preparing the sample for anefiysis was reported (L46).
MISCELLANEOUS In this section, the determination of the concentrations of miscellaneous components such as hydrogen peroxide in water, and the measurement of various chemical characteristics of natural waters are briefly reviewed. These characteristic properties include pH, conductivity, hardness, alkalinity, redox potential, s eciation, com lexation capacity, chemical oxygen demanz, and particdate concentration. Other topics included in this section include sampling and preservation, aqueous standard solutions,, e d preconcentration. This section comprises mainly a listin of selected references, with little discussion of the methofology. A FIA spectrophotometric method for determining HzOz in water was developed based on the reaction of the H2.02 withTi(N)-4-(2-pyridylazo)resorcinol ( M l ) . A complex with an absorption maximum at 508 nm is formed, and the method gives a linear response for HzOz in the range of 1.36-1360 ppb for 100-pLsamples. Another spectrophotometric method has a reported detection limit of 0.3 mM HzOZ (M2). Other methods for determining HZ02 in water are based on fluorometry (M3-M5),UV spectrophotometry (M6),voltamand chemiluminescence (M8-MIO). metry (M7), A chemicallymodified electrode for pH measurement was constructed by electropolymerizing a poly(4,4’-diaminobiphenyl) coating onto a platinum electrode (M1I). Eckert et al. described a liquid junction free probe for the direct measurement of pH, pE, and pHzS (M12). The use of
colorimetric methods for pH measurement has been investigated (M13) as well as methods for measuring the pH of high-temperature water (M14,M E ) . A FIA spectrophotometric method was used to determine the free acidity and total acidity in water samples as small as 4.5 mL (M16). Conductivity measurements are discussed in refs M17M19. The measurement of water hardness is described in refs M20-M26, and the determination of alkalinity is addressed in refs M27-M30. Papers dealin with the speciation of aluminum (M31),chromium (M32, h 3 3 ) , nickel (M34), copper (M35-M37),mercury (M38, M39),lead (M40), thallium (M41), and transuranic elements (M42)have been published. Measurements of particulates/turbidity in waters are described in refs M43-M53, and reviews of this subject are provided in refs M54 and M55. Methods for the preconcentration of manganese (M56),chromium (M57),copper and cadmium (M58),nickel (M59),nickel and cobalt (M60),tin (M61),lead (M62),lead and selenium (M63),arsenic (M64), mercury (M65, M66), mercury and arsenic (M67),uranium (M68), and multiple metals (M6SM79)have been described. As ecta of water sam ling (M80-M85) and preservation (&6-M91) have also {een discussed. Peck and Metcalf (M92)describe an aqueous standard of known conductivity and acid neutralizing capacity. Other aqueous standards have also been discussed (M93-M96).
ORGANIC ANALYSIS Gas Chromatography Reviews. Techniques for the analysis of organicpollutants in waters and wastewaters by gas chromatography (GC)were reviewed by Grob ( N l ) . The uses of graphitized carbon black in GC have been reviewed (N2). The a plications of capillary GC in water analysis were reviewed (E3). The present and future prospects of the field use of GC for on-site monitoring were reviewed (N4). The determination of biogenic organic matter in freshwaters using GC with thermal conductivity detection (N5) and GC methods for the determination of dissolved gases in water samples (N6) were reviewed. Instrumental Techniques. Sample Introduction. Retention index monitoring using thermal desorption GC was developedas a method for the verification of chemicalwarfare agents in aqueous matrices (N7). A data base of GC retention indexes was compiled and applied to the determination of triethyl phosphate, tributyl hos hate, and diethyl malonate. Solid-phase extraction comginelwith programmed-temperature vaporizer injection operating in the solvent-venting mode formed the basis of a method for the determination of toxaphene and polychlorinatedbiphenyls (PCBs) by GC (N8). Detection limits in the low nanogram per liter range were reported. The develo ment of a Curie point headspace sampler for capillary 8 C was reported (N9). A procedure using a continuous two-phase reaction system coupled with on-line capillary GC for the determination of polar solutes in water was described (NlO). The applicability of the method was demonstrated using propionic acid and 2,6-difluorobenzoic acid. A method for determining organic compounds in aqueous samples which utilized the same capillary GC column for both sampling and analysis was reported (Nl!). The effects of sampling velocity, sample volume, sampling temperature, and amount of solute were studied. A technique for the identification of trace levels of organic pollutants in water usin splitless injection onto a Cu(I1) precolumn with capillary 8C-Fourier transform infrared spectroscopy was presented (N12). With this technique it is reportedly possible to eliminate solvent effects completely and utilize a larger volume of sample. A study of systematic errors associated with the use of internal standards as calibrants in headspace GC analysis concluded that it is not possible to eliminate the matrix effect in this method of quantitative GC analysis (N13)). Stationary Phases. A stationary phase with low bleed characteristics was obtained by diluting permethylated heptakis(2,3,6-tri-O-methyl)-j3-cyclodextrin in a OH-terminated polysiloxane (N14). Using this stationary phase the enantiomeric ratio of a-hexachlorocyclohexane was determined. A similar chiral stationary phase, heptakis(3-0butyryl-2,6-di-O-pentyl)-/3-cyclodextrin, was also used to determine the enantiomeric ratio of a-HCH (N15).An enantioselective stationary phase was also reported for the determination of (*)-geosmin (N16).Polycarbonates were ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
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evaluated as stationary phases for ca illary GC analysis of aqueous and acidic samples (N17). Tge major advantage of these columns seems to be their high thermal stability and inertness to water. Detection. Evaluation of GC/matrix isolation infrared spectroscopyfor the analysis of semivolatilepriority pollutants found that this technique is only suitable for semiquantitative work (N18). The ion-trap GC detector was found to be approximately 3 orders of magnitude more sensitive than GC with Fourier transform infrared detection (N19). Organic Acids. A GC method for determining resin and fatty acids in pulp mill wastewaters was described (N20).In this method the target compounds can be isolated by solvent or solid-phase extraction and quantified by flame ionization detection (FID). A method for the analysis of nitrilotriacetic acid (NTA) and EDTA in drinking and surface waters was reported (N21). Enrichment was performed by anion exchange. Detection limits were 0.5 and 1.0 pg/L for NTA and EDTA, respectively. A GC method was developed for the determination of low molecular weight carboxylic acids in aqueous samples based on derivatization of the acids to 2-nitrophenylhydrazides (N22). Using nitrogen-selective detection with a thermionic-specific detector, detection limits were as low as 0.8 pmol. A procedure was presented for the quantitation of DBP, dimethyl o-phthalate and DOP in wastewaters from plasticizer manufacture (N23). Using FID, detection limits were reported as low as 0.005 mL/L. The primary hydrolyzate of the toxic military agent lewisite ((2chloroviny1)arsonousacid, CVA) can be determined at trace levels by GC with flame photometric detection (FPD) after CVA has been derivatized with 1,a-ethanediol to form the stable cyclic disulfide (N24). The method was reportedly ap licable to samples with CVA concentrations in the low !p range. The 2-ethylhexylester of acrylic acid was extracted Ey a stream of nitrogen, captured on SE-30/Chezasorb AWHMDS column and quantified using GC with FID (N25). The detection limit was 0.0001 mg/L for 100-mL samples with a 0.2 L/min nitrogen flow rate. Nitrogen-Containing Compounds. Capillary GC with cold on-column injection and nitrogen-specific detection was used to quantify 13 substituted anilines in drinking and surface water samples (N26). Reported detection limits were approximately 0.025 pg/L. A method was described for the determination of nitroaromatics and nitramines in groundwater and drinking waters using a DB-1301wide-borecapillary GC with electron capture detection (ECD) (N27). Method detection limits for 2,6-dinitrotoluene, 2,4-dinitrotoluene,and 2,4,6-trinitrotoluene, cyclotrimethylenetrinitramine,and cyclotetramethyelenetetranitraminewere 0.003,0.04,0.06,0.3, and 6.0 pg/L, respectively. Trace amounts of acrylamide were determined in seawater samples by capillary GC with ECD after conversion to 2-dibromopropenamide (N28). The detection limit reported was 0.02 pg/L. A GC-ECD method for determining dinitrotoluene reported a detection limit of 2 ng/L for 1-L water samples (N29). Gas chromatography with nitrogen-specific detection was used to measure concentrations of nitrophenols in precipitation (N30). The analytes were first methylated with diazomethane. Miscellaneous Compounds. A method was reported for the determination of trace levels of benazol I1 (N31). A method for the determination of phenol reported a detection limit of 10 pg/L and a precision of 5% (N32). Polar organic compoundssuch as diols, henols and acids could be measured usin static headspace G 8 if the analytes are first derivatized by a%dingMeZS04 to the sample vial (N33). Two analytical procedures for the determination of aldehydes and ketones (PFBOA) de(the 2,3,4,5,6-pentafluorbenzyl)hydroxylamine rivatization GC method and the 2,4-dinitrophenylhydrazine high- erformance li uid chromatography method) were comparef(N34). The $FBOA GC method was found to have lower detection limits. Dichloropinacolin was preconcentrated by extraction with toluene and analyzed by GC on an Inerton-Super column coated with 3-5% SE 30, OV 17, or Carbowax 1500using a constant recombination-rate detector (N35). Adachi and Kobayashi (N36)report a GC-FID method for the determination of benzene. A method for the quantitative determination of dimethoate with liquid-liquid extraction and GC-ECD ave a detectionlimitof 0.1 ng (N37). A GC-based method for tetermining camphor and bornylene in water has a detection limit of 0.04 ppb (N38). A procedure 266R
ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
was developed for the determination of 2-ethoxyethyl acetate and the material it is produced from, 2-ethoxyethanol and acetic acid, using GC with thermal conductivity detection (N39). The determination of monofurfurylidene acetone and difurfurylidene acetone in natural waters using GC with ECD was described (N40). A procedure for the determination of O,O-bis(2-ethylhexyl)phosphorodithioicacid in water which includes extraction of the analyte as its Bi(II1) complex followed by derivatization with pentafluorbenzyl bromide and subsequent determination by GC with ECD was reported (N41). The detection limit at a signal/noise ratio of 3:l was 1 pg. Gas chromatography with nitrogen-phosphorus detection was used to quantify volatile amines in seawater and sediment porewater samples a t microgram per liter concentrations (N42).
LIQUID CHROMATOGRAPHY AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY Instrumentation.The use of electrodialytic sample treatment coupled on-line with column liquid chromatography (LC) has been described and applied to the analysis of a variety of sulfonic acids, paraquat and diquat (01). The on-line coupling of zone electrophoretic and isotachophoretic sample treatment with LC has been demonstrated using bentazone in river water (02). Hendriks et al. (03)describe the couplin of on-line isotachophoresis with high-performance li ui! chromatography (HPLC). The development of an online membrane interface for the LC analysis of trace levels of phenols in wastewaters has been reported (04,05). Selectivity is obtained by controlling the pH of the extraction medium. The application of this analytical system to the determination of several chlorinated phenols a t the ppb level was described. Goosens et al. (06) investigated the feasibility of on-line reversed-phase (RP) LC-ca illary GC using an on-column interface. Using a 1-mm (i& LC column and the retention gap technique, a functioning system was developed. The deterioration of chromatographic peak profiles (e.g., peak height, peak width, and retention time) was found to be inversely related to the amount of organic solvent present in sample solutions (07).Sulyaet al. have described on-column sampling, preconcentration, and both thermal and transient mobile-phase gradient separation using microbore LC (08). The use of quenched and sensitized lanthanide luminescence for detection in LC has been described by Schreurs et al. (09). Phenols and Related Compounds. With the modeling surface response method it was possible to optimize the separation of several phenolic compounds (010). The overlapping resolution method was applied to predict the best mobile-phase compositionfor the separation of 11substituted phenols on a RP column (011). A method was described for the determination of phenol as a dansyl derivative by HPLC with UV detection (012). The derivatization is based on the heterogeneous reaction of phenol in a basic aqueous phase with dansyl chloride using tetra-n-pentylammonium bromide as a phase-transfer catalyst. The detection limit with a 10pL sample injected was 1.1nM phenol (S/N = 2). Phenol concentrations in the nanogram ran e can be quantified by normal- or reversed-phase HPLC J t e r derivatization with dansyl chloride (013). The utility of porous graphite as a HPLC stationary phase was shown for phenols, di- and trihydroxybenzenes, aminophenols and a variety of other compounds (014). This material was reported to have higher capacity factors for polar analytes than either RPR-1 or CISSiOz. An isocratic, RP HPLC procedure using dual-electrode amperometry was reported for the separation and determination of chlorophenolic compounds (015).Dual glassy-C electrodes were used in a parallel configuration in a thinlayer flow cell with differential current measurement. A HPLC voltammetric method was proposed for the determination of phenol, alkylphenols, hydroxyphenols and cholorophenols (016). The method relies on a dual-detector system to achieve detection limits ranging from 55 pg for hydroquinone to 19 ng for pentachlorophenol. The determination of alkyl-, nitro-, and chlorophenols usin a twophase precolumn dansylation and postcolumn photofysis and peroxyoxalate chemiluminescence has been described (017). Detection limits of 0.01-0.1 ng/mL were achieved. The
WATER ANALYSIS
determination of 11substituted phenols identified as priority pollutants using HPLC and UV detection has been reported (018). Detection limits ranged from 60 pg to 100 ng. Nitrogen-ContainingCompounds.Two HPLC methods were developed for the selective determination of MeNHz and MezNH in wastewaters after derivatization with phenyl isothiocyanate and p-toluenesulfonyl chloride (019). A method relying on precolumn derivatization of primary and secondary amines to sulfonamides by their reaction with dansyl chloride was found to be able to determine lower concentrations of these com ounds than methods using (020). derivatization with 1,2-naphtkoquinone-4-sulfonate Hi h- erformance liquid chromatography with electrochemicaf Ztection usin amperometry with Au and lassy-C electrodes was use$ to quantitate o-toluidine, 4-cghloro-2methylaniline, diphenylamine, benzidine, and 3,3-dichlorobenzidine in water (021). Using pulsed amperometry with Au electrodes it was possible to detect 1pg of diphenylamine at a signal-to-noise ratio of 2; using glassy-C electrodes the detection limit was lowered to 0.48 pg. An ion interaction RP HPLC method was resented that reported the ability to separate aromatic anfaliphatic amines, as well as nitrate and nitrite, using two interacting agents, oct Iaminium salicylate and octylaminium orthophosphate (622). The sha e and retention of peaks in the RP HPLC determination and trialkylamines were found to improve upon the of addition of ammonium ion to the mobile phase as a competing base (023). Using amperometric detection, this lowered the detection limits to a few tenths of a milligram per liter for direct injection of aqueous samples. Postcolumn reaction electrochemical detection and on-line reenrichment was reported to significantly improve upon existing methods for the determination of N-chloramines in water (024). A reaction buffer for the derivatization of amino acids in seawater with o-phthaldialdehyde-2-mercaptoethanolwas described by Wenck et al. (025). The derivatized amino acids were determined by HPLC with fluorometric detection. Walsh (026) describes a method for the determination of nitroguanidine in groundwater samples. Miscellaneous Compounds. Frimmel et al. (027) described the characterization of some components of humictype organic substances using LC and various detectors. Resin acids in effluent and water samples were determined by converting them to the (7-methoxycoumarin-4-y1)methyl (MMC) ester or the (7-acetooxycoumarin)methyl(MAC)ester (028). The detection limit of the MMC ester by UV absorption at 318 nm was 20 pg/L; the MAC esters can be detected at concentrations lower than 1pg/L using fluorescence. A procedure for the determination of low molecular weight oxocarboxylic acids and carbon 1 compounds in estuarine and marine samples was reporteiby Edelkraut and Brockman (029). Detection limits ranged from 17 ng/L for glycoaldehyde to 500 ng/L for cyclohexanone. Methods for the determination of phthalate esters were described by Wu (030) and Zhou and Gu (031). A flow-injection procedure combining HPLC with postcolumn derivatization with 3-methyl-2-benzothiazolinone was developed to measure aldehydes in fog water samples (032). A method for the determination of all inositol phosphate congeners using P-specific detection was developed (033). P-specific detection was achieved by postcolumn illumination with hi h-intensity UV radiation and the formation of reduced pios homolybdate by flow injection of an ascorbic acid/molyb&te reagent. Submilligram levels of P could be detected with 50-250-pL injections. Reducing and nonreducing sugars, including sugar alcohols, were determined in seawater without reconcentration using triple-pulsed amperometry (034).T\e detection limits for mono- and disaccharides were 2-10 nM with a signal-to-noise ratio of 3. Column switching with two Cle separation columns combined with UV detection a t 233 nm was used to determine ethylenethiourea in groundwater samples at concentrations as low as 1ppb (035). With preconcentration of the samples, the detection limit could be decreased to 0.1 ppb. Doerge et al. (036')reported a HPLC method using pulsed amperometric detection at a Au electrode to measure residue levels (as low as 5 ppb) of ethyIenethiourea in groundwater. Trace amounts of Brilliant Blue FCF in water were determined by concentration on a Florisil PR column, elution with methanol, and quantitation by HPLC (037). The
8-
reported method detection limit was 0.1 pg/L. A technique for the determination of Rhodamine WT was based on the combined application of CISsolid-phase extraction and HPLC with fluorescent detection (038). Detection limits were in the 10 p /L range. An analytical procedure using a sweptpotentiaf electrochemical detector and HPLC for the identification and quantitation of the hydroxy and vinyl sulfone derivatives of Reactive Blue 19 in textile wastewaters was developed by Camp and Sturrock (039). The detection limit was reported to be in the ppt range without preconcentration. An isocratic LC system with UV detection at 230 nm was develo ed for the rapid trace-level (sub microgram per liter level) ietermination of a large number of polar pollutants in water (040). The system contains two precolumns, in series, which are packed with a styrene divin lbenzene polymer. The second precolumn is loaded with so$um dodecyl sulfate before analysis. A HPLC technique with amperometric detection for the direct injection of water samples containin as little as 1ppb amitrole was developed by Pachinger et af (041). A HPLC method for determining a number of chlorobenzenes in drinking water reported minimum detection limits that range from 7.8 ng/mL for p-dichlorobenzene (042). A HPLC to 19.3ng/mL for 1,2,4,5-tetrachlorobenzene method was reported for the trace-level determination of thiodiglycol in surface water and seawater using fluorineinduced chemiluminescence detection, which is highly selective for reduced organosulfur compounds (043). Detection res onse was linear over a concentration range covering 3 or8,rs of magnitude (4-400 ng injected) with a minimum detection limit of ca. 4 ng (S/N = 3).
MASS SPECTROMETRY Reviews. The applications of gas chromatography-mass spectrometry (GC-MS) to the analysis of organic compounds present in water samples has been the subject of several reviews since this review was last compiled (Pl-P4). The use of liquid chromatography mass spectrometry (LC-MS) in the determination of organic compounds in water has also been the subject of a recent review (P5). Liquid Chromatography-Mass Spectrometry. Particle beam (PB) LC-MS using an anion exchange column was used to identify aromatic sulfonic acids (P6)and alkylphenol polyethoxylates (P7). Approximate1 100 of the 126 olar, water-soluble compounds on the U.$. EnvironmendProtection Agency's (EPA) National Pesticide Surve can be analyzed by P B LC-MS (P8).Particle beam LC-Mi showed sufficient sensitivity so that 43 of these compounds were detectable a t amounts of 5100 ng. A comparison of P B LCMS with GC-MS showed that PB LC-MS was able to detect an additional 43 compounds in water samples taken from a demonstrated water treatment facility (P9,P16). Hsu (P10) the feasibility of coupling ion chromatography with mass s ectrometry through a particle beam interface for the &termination of organic anions. Thermospray LC-MS has been used to identify the presence of the nerve agent VX (0-ethyl S-2-diisopropylaminoethyl methylphosphonothioate) (P11,P12). Electrospray tandem mass spectrometry was used to detect and quantify hydroxymethanesulfonate in precipitation sam lea (P13). Concentrations as low as 0.6 pM were detectaile. Several nonbiodegradable, hydrophilic organic substances in industrial and municipal wastewaters were identified using LC tandem mass spectrometry (P14, P15). Membrane-IntroductionMass Spectrometry.A hollowfiber membrane flow-cellinterface for mass spectrometry has been described (PI7). The interior of a siliconerubber hollowfiber membrane is continuously purged with He while an aqueous solution containing the analytes flows continuously over the exterior membrane surface. Membrane introduction mass s ectrometry (MIMS) has been used to detect: low molectfar weight (c1-C~)aldehydes a t concentrations as low as 1ppb without preconcentration (P18); organic contaminants in biological wastewater treatment (P19)chloramines (P20-P21); and volatile organic compounds present at concentrations in the low microgram per liter range (P22). A membrane robe for use with portable GC-MS systems has been descriged (P23). Gas Chromatography-Mass Spectrometry.Qualitative analysisof chloroligninsand lignosulfatesin pulp mill effluents ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
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WATER ANALYSIS
has been erformed using pyrolysis (PY) mass spectrometry and PY 8C-MS (P24). Monochloroguaiacol was the most abundant structurally specificaromatic chloroligninpyrolysis product. Bruchet et al. (P2.5)used PY GC-MS to characterize high molecular weight THM precursors and other refractory organic substances in water. A thermal purge-and-trap GCMS was judged suitable for the low-level quantitation of 2-methylisoborneol and geosmin (P26). Lesage (P27) demonstrated the ability of dynamic thermal stripping GC-MS to identif a number of organic compounds in water including aniline, hoxane and various phenols. A spray extraction technique and sorption tube were used in a GC-MS method for the determination of volatile organic compounds (P28). This “spray and trap” technique has detection limits as low as 10 ng/L. A method for determining MezS in seawater by isotope dilution GC-MS was reported (P29). A purge-andtrap technique is used to preconcentrate the Mez&Deuterated Me# served as the internal standard. An isotope dilution GC-MS method for the determination of dimethyl sulfoxide (DMSO) was also reported (P30). DMSO was reduced to dimethyl sulfide (DMS), followed by purge-and-trap concentration. The internal standard was DMS-de. The detection limit reported was 0.01 nM. A method using a packed GC column directly coupled to the vacuum system of a MS was reported by Hille (P31). Pressure reduction for sample introduction into the MS was accomplished by immersing the GC column in liquid nitrogen. Detection limits in the nanogram per gram range for chlorinated and aromatic hydrocarbons were reported. The advantages of GC-MS selected-ion monitoring (SIM) in the mass-profile mode at medium resolving power were investigated for analyses requiring detection of low picogram amounts of analytes in complex mixtures (P32). Mass-profile monitoring provides a certainty at least 10 times greater than conventional GCMS SIM analysis. Greaves et al. (P33) found negative-ion chemical ionization GC-MS to be more specific for PCBs than GC with electrolytic conductivity detection. Hehzadi et al. (P34)described an isotope dilution GC-MS technique for quantification of 4,4’-DDT, 4,4’-DDD, and 4,4’-DDE with detection limits in the low parts-per-trillion range. A GCMS SIM method for the determination of pentachlorophenol and carbaryl reported detection limits of 0.08 and 0.11 pg/L, respectively (P34). Mobile Mass Spectrometers for On-Site Analysis. Several mobile GC-MS systems for on-site analysis of contaminants were described (P35-P40). MiscellaneousCompounds.A method was developed for the determination of 3-chloro-4-(dichloromethyl)-5-hydroxy2(5H)-furanone in water samples using high-resolution MS with E1 ionization and SIM (P41). The detection limit at a signal/noise ratio of 3:l was 0.6 ng/L. Deuterium-labeled geosmin and methylisoborneol were investigated as internal standards for the determination of each compound in water samples by GC-MS (P42). When used as internal standards these compounds gave better precision and accuracy than chloroalkanes. Fifteen different hydrophilic compounds present as contaminants in water samples were analyzed by GC-MS with SIM using perdeuterated p-dioxane and DMF as internal standards (P43). Anthraquinonesulfonates in river water samples were collected by anion exchange and quantified by GC-MS SIM (P44). The detection limits reported for anthraquinone-1-sulfonate and anthraquinone-2-sulfonate were 0.005 and 0.02 ng, respectively. Trace levels of DMF could be determined by capillary GC-MS with SIM in a method developed by Okamoto et al. (P45). The detection limit was reported as 0.055 pg/L. A method for the determination of triethylamine in river water with a detection limit of 0.15 pg/L was described (P46). Aromatic amines such as 3,3’-dichlorobenzidine and 3,3’-dichloro-4,4’-(diaminopheny1)methane were determined by GC-MS as their trifluoroacetyl derivatives (P47). Concentrations in water as low as O.OO0 04 and 0.000 08 pg/g, respectively, could be detected. A study to validate the use of 0-(2,3,4,5,6-pentafluorobenzy1)hydroxyamine hydrochloride as a derivatizing agent for the quantitative determination of aliphatic mono- and dialdehydes was reported (P48).Several methods for the determination of dioxins and/or dibenzofurans were described (P49452). 288R
ANALYTICAL CHEMISTRY, VOL. 65, NO. 12, JUNE 15, 1993
PHOTOMETRY AND SPECTROPHOTOMETRY Reviews. Churilova ( I ) reviewed hotocolorimetric methods for determining car ohydrates Based on their reaction with o-toluidine. Capitan et al. (Q2)reviewed trace analysis using solid-phase spectrophotometry. Fluorescence. Trace levels of thiamine in water samples were determined by oxidizing it with potassium ferricyanide at pH 13to give the fluorescent thiochrome (Q3). A detection limit of 0.8 ppt was reported. Fluorescence spectroscopy at 77 K was used to determine 1,2-benzopyrene, 1,12-benzopyrene, and 1,2-benzanthracene in waters in contact with petroliferous geological formations (Q4). A synchronous excitation fluorescence technique was developed for the monitoring of effluents from a dye manufacturing facility (Q5). The effect of various sample characteristics on the anal sis was explored. Fluorescent membrane formulations for dretecting organic nitro compounds based on fluorescent quenching were evaluated by Jian and Seitz (86). The most sensitive membrane was prepared by solvent casting from cyclohexanoneto incorporate p enebutyric acid into cellulose triacetate plasticized with isog& diphenylphosphate. Detection limits for 2,4,64rinitrotoluene and 2,4-dinitrotoluene were ca. 2 mg/L. Concentrations of disodium 4,4’-dithiobis(benzenesu1fonate) as low as 0.5 mg/L in electroplating wastewaters were determined by measuring the fluorescent intensity (522 nm) of the acridine orange complex (Q7). Methanol in environmental water samples was oxidized to formaldehyde, and the resulting formaldehyde reacted with J-acid to form a yellow dye with reen fluorescence havin a 1” of 470 nm (QB). Dissolved cfouble-stranded DNA a n i RNA in seawater were concentrated on a hydroxyapatite column and determined fluorometrically usin ethidium bromide dye which binds specifically to the doubfe-stranded polynucleotide (89). The detection limits were 0.6 and 1.1 pg/L for DNA and RNA, res ectively, concentrated from a 5-L sample. Chlorophyll Q antfchlorophyll b were determined by micellar-enhanced spectrofluorometry (810). The optimization of method variables is also discussed. Phosphorescence. Nakaguchi et al. (811)described a method for the phosphorimetric determination of amino acids in natural waters utilizing their fluorescamine complexes. The detection limit is 1nM. Acetone in water was determined by sensitized room-temperature phosphorimetry (QI2). Acetone was excited at 274 nm and the phosphorescence intensity of biacetyl measured at 515 nm. The reported detection limit was 7.9 X 1V M. A room-temperature phosphorimetric method for the determination of 2-naphthol in wastewater with a detection limit of 1.44 X 10-6 M was developed by Zhu and Pan (Q13). Flow Injection Analysis. Flow injection procedures for the s ectrophotometric determination of phenol in water by two gfferent reactions were reported by Frenzel et al (Q14). The 4-aminoantipyrine reaction (detection limit re orted as 30 pg/L) and the oxidative coupling of 3-methyl-2-Benzothiazolinehydrazone (detection limit reported as 12 p /L) formed the basis for these methods. Safavi and Ensafi ( b 5 )report a flow in’ection method for the determination of trace levels of formekdehydebased on its inhibition of the Brilliant Greensulfite reaction at pH 7. Concentrations of formaldeh de as low as 20 ng/mL could be detected. The reduction of &quat and paraquat with alkaline sodium dithionite was applied to the determination of both herbicides using a flow injection system (Q16). Kester et al. (Q17) compared several flow injection methods for the determination of abietic acid. Miscellaneous Methods. Vredenbregt et al. (818) used cryotrapping GC-Fourier transform infrared (FTIR) spectroscopy to identify the photolysis products of chloronitrobenzene isomers. Gas chromatography-matrix isolation infrared spectrometry was found to be suitable only for semiquantitative analysis using currently available instrumentation (819). Low ppb-range detection limits were possible for many aromatic and chlorinated hydrocarbons in water using sparging FTIR (Q20). Surface enhanced Raman spectroscopy was judged to be a capable tool for detecting a wide range of organic contaminants in groundwater at concentrations as low as the ppb-range (Q21). An instrument suitable for on-site and in situ measurements was described. Miscellaneous Compounds. Photometric methods were described for ethoxylated alkyl phenols (Q22),polyethylene
8,
WATER ANALYSIS
polyamines (Q23),and olyacrylamides (Q24-QZ5). A spectro hotometric metho1 for pyridine based on its reaction wit[ cyanogen bromide to form glutaconic aldehyde and its subsequent condensation with 6-amino-1-naphthol-3-sulfonic acid (J acid) to form a yellow dye havjng a maximum absorbance a t 400 nm with a Sandell’s sensitivity of O.OO0 18 pg/cm2 was re orted (Q26). Bhattacharjee et al. (Q27) converted pyri8ne to glutaconic aldehyde and then reacted it with 4-aminosalicylic acid to form the basis of a method with a detection limit of 0.025 ppm. The carcinogen 2-naphthylamine was detected in waters and wastewaters a t levels as low as 0.2 pg using UV spectrophotometry (Q28). The oxidative couplin of aniline and guaiacol using N-chlorosuccinimide at pcfI 10-11 produced a blue dye with an absorbance maximum at 615 nm (Q29). Using this reaction, aniline could be determined s ectrophotometrically a t levels as low as 1 ppm. N-Methyl!is(@-hydroxyethy1)amine was determined in water samples by extraction with ether, treating the extract with citric acid, and spectrophotometric measurement of the yellow complex at 400 nm (Q30). It was found that tertiary amines would interfere with the determination. A method for the quantification of hemediterbutylperoxy-3,3,5-trimethylcyclohexeperoxide (dihydroisophorone peroxide) in water was presented based on its extraction with benzene and reaction with N,N-dimethylp-phenylenediamine in benzene-ethanol (Q31). The detection limit reported was 1.3 pg. A spectrophotometric method for determining hecogenin in wastewaters described by Xu and Tan (Q32)has a relative standard deviation of
