Water analysis - Analytical Chemistry (ACS Publications)

Water Analysis M. J. Fishman and D. E. Erdmann U S . Geological Survey, Lakewood, CO 80225

This sixteenth review of the literature of analytical chemistry applied to water analysis covers the period from October 1972 through September 1974. The present review follows the plan of the previous reviews, the last of which appeared in ANALYTICALCHEMISTRYfor April 1973 (11); however, the editors of ANALYTICAL CHEMISTRYrequested that the review authors cover their respective fields in a critical, selective manner, and n o t attempt to provide an all-inclusive bibliography. The material used in preparing this review comes mainly from major analytical journals and chemical abstracts. Conference proceedings, obscure foreign journals, and most trade journals are generally excluded. The summary of each article is shorter than in the past and the reader should refer to the specific journal or chemical abstract for the details. A review of the literature on water pollution control, which includes a section on analytical methods and instrumentation is published annually by the Water Pollution Control Federation. The 1972 review by Carlton, Smith, and Walters (6), Andelman (2), Ghosh (13),Minear et al. (23), and Herbes and Allen (15) includes 478 references and covers such topics as major inorganics, trace inorganics, water characteristics, organics, continuous monitoring, automated analysis and sampling procedures. The 1973 review by Carlton, Smith, and Walters ( 5 ) , Allen et al. ( I ) , Ghosh and Brown (I4);Minear and Pagoria (24), and Brezonik (4) includes 475 references and covers the same topics. L. Ciaccio edited the Water and Water Pollution Handbook for 1973. The handbook includes the following reviews: Electrochemical techniques in water analysis by Maienthal and Taylor (20); Luminescence techniques in water analysis by St. John (32); Monitoring of water systems by McNelis (22); Infrared spectroscopy in water analysis by Parker (28);Determination of radioactive nuclides in water by Kahn (18);Automated and instrumental methods in water analysis by Ciaccio, Cardenas, and Jeris ( 7 ) ; Mass spectrometry in water analysis by Roboz (30); Gas chromatographic Analysis of water and waste waters by Cukor and Madlin (9); and The determination of minor metallic elements in the water environment by Cosgrove and Bracco ( 8 ) . Guidelines establishing test procedures for analysis of pollutants are reported in the Federal Register on October 16, 1973 (3). A list of references to 71 test procedures is given for measurement of pollutants for which an effective limitation is specified under the Federal Water Pollution Control Act Amendments of 1972. A review with 49 references on instrumental analysis for water pollution control was prepared by Ishimaru ( 1 7 ) .Determination of trace metals in environmental samples by mass spectrometry, atomic absorption, gas chromatography, neutron activation, ESR, and the ring-oven method are discussed by Leh and Chan (19). Morrison (26) reviewed applications of spark-source mass spectrometry to

Authors have not been suppiled with free reprints for distribution. Extra copies of the review issue may be obtalned from Special lesues Sales, ACS, 1155 16th St., N.W., Washington, DC 20038. Remit $4 for domestic U.S. orders; add $0.50 for additlonal postage for foreign destinations.

334R

0

the multielement analysis of samples of importance in the geochemical environment including water. The principles of the analytical techniques are discussed briefly. Moriyama (25) reported that X-ray fluorescence analysis is a rapid and convenient method for pollution analysis. Veening (33) reviewed recent developments in instrumentation for liquid chromatography which includes a section on pollution applications. Frant (12) reported on the application of chemical-sensing electrodes for detecting pollutants. The review covers analytical methods, detection limits, low-level problems, and lowering of the detection limits. The theory and applications of different electrometric methods for measuring ion concentrations in monitoring toxic and loading materials in surface, drinking, industrial, and waste waters, including potentiometry, amperometry, and coulometry are reviewed by Oehme (27). Ediger (10) reviewed methods of collecting samples of water for analysis. Hinge (16) prepared a review containing 14 references in sampling and analysis of chemical pollutants in river water. Analysis, sampling, and monitoring are discussed in a review by Whitby (34) on pollutant determination in natural and waste waters. In a review with 16 references, commercial instruments currently in production and useful in providing data for measuring the quality of fresh, waste, and saline waters are discussed by Phillips, Mack, and MacLeod'(29). Chemical analysis and interpretation of chemical parameters, new methods of chemical analysis, and sampling methods in dynamic systems where both concentration and form can change with time are reviewed by Smythe (31). The nature of the aquatic environment, the objectives, parameters, and methods suitable for measurement systems, and the design of water quality surveillance programs are discussed by Mancy (21).

ALKALI METALS Van de Winkel et al. (1OA) described an AutoAnalyzer system for the automatic potentiometric determination of sodium in river and mineral waters in the 1- to 100-ppm concentration range. A description of the flow diagram and flow-through cell are given. Accuracy and reproducibility are excellent. Denisova ( 4 A ) used ion-selective electrodes for the automatic monitoring of sodium ion content in the feed waters of thermal electric power plants. Two types of glass electrodes were used. Afanas'eva, and Oradovskii ( I A ) determined the sodium content of sea water with a glass sodium-ion-selective electrode. The electrode system measured the sodium concentration over the range of 0.06 to 26.3 glkg. An indirect polarimetric determination of sodium in sea water is described by Kulev and Bakalov ( 7 A ) . Sodium is precipitated with zinc uranyl acetate. The precipitate is dissolved in water and mixed with D-tartaric acid at pH 5 . The optical rotation is proportional to the uranium content. An indirect amperometric titration method for the determination of sodium in sea water based on the fractional precipitation of sodium ion with zinc uranyl acetate is reported by Kulev, Stanev, and Bakalov ( 8 A ) . The precipitate is collected, dissolved in water, and zinc determined by titration with potassium ferrocyanide. Anfalt and Jagner (2A) determined the potassium content of sea water potentiometrically by standard addition with a potassium-selective valinomycin electrode. A computer-processed titration procedure is used. An indirect polarographic method for determining potassium in waters of high salinity is reported by Marczak and

ANALYTICAL CHEMISTRY, VOL. 47, NO. 5, APRIL 1975

Marvin J. Flshman, born in Denver, Colo., received his BA degree (1954) and MS degree (1956) from the University of Colorado. He has been employed by the Water Resources Division, US. Geological Survey, Denver, since 1956. His research interests are centered on development of methods for water analysis, including atomic absorption. He is a member of the American Chemical Society, the Society for Applied Spectroscopy, and the American Society for Testing and Materials (Mr. Fishman serves on ASTM Committee D-19 on water). He has published about 20 papers related to methods for water analysis.

David E. Erdmann has been a chemist with the Water Resources Division of the U.S. Geological Survey since 1968. He received his BS degree from Winona State College and his MS and PhD degrees from the University of Nebraska. His research interests are concerned with the development and automation of methods for water analysis. He is a member of the American Chemical Society, Sigma Xi, and Phi Lambda Upsilon Societies.

Ziaja ( 9 A ) .Potassium is precipitated as the tetraphenylborate. The precipitate is dissolved in acetone followed by precipitation of acetone-insoluble thallium tetraphenylborate. Excess thallium ions are determined polarographically. The method permits the determination of 375 to 1125 mg potassium with an error of f 3 . 5 to 6.2%. Ikeda and Hirata ( 5 A ) used an indirect amperometric procedure for determining potassium in sea water. The potassium is precipitated with excess sodium tetraphenylborate, and the excess tetraphenylborate ion is titrated in a supporting electrolyte with a silver nitrate solution by short-circuit amperometry a t a rotating platinum wire electrode. Halides interfere and must be titrated separately. Ben-Zwi ( 3 A ) described an atomic absorption spectrophotometric method for determining lithium in highly salted solutions, such as the Dead Sea, by standard addition. Khasanov, Khudaibergenov, and Umarov ( 6 A ) used radioactivation to determine rubidium and cesium in ground waters. The method is based on the characteristic y-ray spectral lines of 1.08 and 0.60 MeV. The dry residue is irradiated along with standards for 10 hours with a flux of 1.8 X loL3neutrons per cm2 second. The rubidium and cesium are then chemically separated. Reproducibility is 10 to 15%.

HARDNESS, ALKALINE EARTH METALS Ashizawa and Yanagi ( 2 B ) determined calcium in river water photometrically with 1-(l-carboxyphenylazo)-2naphthol-3,6-disulfonic acid in an alkaline medium. Aluminum, magnesium, iron(II), copper, zinc, and nickel up to 10 ppm do not interfere. Iron(III), phosphate, bicarbonate, sulfate, and nitrate interfere a t 1 ppm. A computerized photometric titration procedure for the determination of calcium in sea water in the presence of magnesium is described by Jagner (8B).The calcium is titrated with a standard tetrasodium-EGTA solution using zinc-zincon as indicator. Ten sets of measurements, each consisting of 20 titrations of 20- to 25-g sea-water samples, yielded a mean value with a standard deviation of 0.00028. Searle and Kennedy (13B) described a high-temperature flame-emission method involving the use of the nitrous.

oxide-acetylene flame for determining calcium in rain water. A detection limit of 0.0002 pglml or calcium is obtained a t the 422.7-nm atomic resonance line. Potassiumchloride solution is added to suppress flame ionization. The method described is compared with the bis(2-hydroxypheny1imino)ethane colorimetric method over the 0 to 2 pg/l. range and is shown to be more accurate and less susceptible to contamination. Hulanicki and Trojanowicz (7B) investigated the effect of the composition of solutions in the direct potentiometric determination of total calcium in water with a calcium-selective electrode. They found it necessary to add ammonium buffer to maintain constant pH, potassium nitrate for constant ionic strength, iminodiacetic acid for constant complexation of calcium, and acetylacetone to mask magnesium. In the range of 20 to 800 mg/l. of calcium, the errors of the results did not exceed 4%. Murozumi and Nakamura (IOB) used isotope dilution mass spectrometry to determine calcium in snow a t the ppb level. Bakulov and Mikhailova (3B) determined magnesium in water by atomic absorption using an acetylene-air flame. They found that the magnesium absorption increased if the ratio of acetylene to air was increased. The interferences of Al, Ca, K, Na, HzS04, and HC1 were studied. Sato and Momoki ( I Z B ) presented a new photometric titration method for the determination of calcium and magnesium in tap, well, and sea water. Calcium and magnesium in one solution are titrated with EGTA and DCTA, successively, a t pH 11 using Phthalein Complexon as indicator. The end point for calcium and magnesium can be obtained directly on a successive titration curve. The influences of various foreign ions were studied. Sub-mg quantities of calcium and magnesium can be determined with standard deviations of 0.5% or lower in the presence of many other metal ions. Cheng and Cheng (5B) reported that magnesium can be selectively determined potentiometrically with a divalent electrode in the presence of most other polyvalent metal ions at a pH of 7. The procedure is satisfactory for sea water if the sample is diluted 1:lOO to decrease the salt concentration below 1 X 10-2M. Hulanicki and Trojanowicz ( 6 B ) determined calcium and magnesium in water potentiometrically with a calcium ionselective electrode. EDTA, EGTA, CyDTA with sodium or tetramethylammonium ions were the titrants used. Yakimets and Sekretar (16B) modified a trilonometric method for water hardness, which gives a sharper color change a t the equivalence point. This was achieved by the addition of a zinc salt prior to the titration. Copper interference is eliminated by adding a solution of sodium diethyldithiocarbamate. The determination error is of the order f0.06 pg equiv./l. Sixta, Miksovsky, and Sulcek (I4B) used atomic absorption spectrophotometry for the determination of barium in water. Barium is concentrated and separated by ion exchange prior to its determination. Sulfate up to 2000 mg/l., calcium up to 3000 mg/l., and sodium up to 5000 mg/l. do not interfere. Higher concentrations of sodium displace the barium from the ion-exchange column (Dowex 50W-XS). Supatashvili, Makharadze, and Marsagishvili (15B) described a phototurbidimetric method for determining traces of barium in natural waters. Barium sulfate suspensions are used as standards. If the barium concentration is below 2 mg/l., it is coprecipitated with lead sulfate. Ethanol and ethylene glycol are present along with sulfate in the precipitation reagent. For obtaining consistent results, temperature, ionic force, pH, and rate of inflow of solutions are controlled, which influence the particle size of the suspension.

ANALYTICAL C H E M I S T R Y , V O L . 4 7 ,

NO. 5 ,

A P R I L 1975

0

335R

Ohta and Sasaki ( I I B ) determined strontium by atomic absorption spectrophotometry using standard addition, and reported that the dilution ratio of a natural water sample containing an interfering element can cause significant deviation. Determinations of 25 mg/l. of strontium in t h e . presence of 12.5 mg/l. of aluminum as an interfering element were made on solutions ranging in dilution from 1 to 1/32. Accurate results were obtained a t a dilution ratio of 1/25 or greater. Abdullaev, Khakimov, and Khasanov ( I B ) used neutron activation to determine strontium in natural water. The sensitivity of the method is 1 X g/ml of strontium with relative standard deviations of 5 to 15%. Bernat, Church, and Allegre (4B) reported that the determination of barium and strontium directly from sea water by isotope dilution mass spectrometry is an efficient, precise, and virtual blank-free procedure. Kornienko and Samchuk (9B)described a chelation-extraction colorimetric method to determine beryllium in natural waters. The sensitivity of the method is 0.04 pglml. Disodium dihydrogen ethylene tetraacetic acid, carbon tetrachloride, and beryllon are used for the chelation, extraction, and color formation.

ALUMINUM, IRON, MANGANESE, AND CHROMIUM The feasibility of determining the extractable aluminum contents of natural waters, with particular emphasis on sea water, by gas-liquid partition chromatography was demonstrated by Lee and Burrell ( I I C ) . Aluminum is chelated with trifluoroacetylacetone, extracted into toluene and injected into the chromatograph using direct on-column injection. Picogram quantities are detected. Zhukhovitskaya and Sokolovskaya (23C) reported that the precision of the colorimetric Eriochrome Cyanine R method for aluminum depends both on concentrations of aluminum and iron and on their ratio. With approximately equal concentrations of 8 pg/l., the relative error is f2.5% if 0.005 or 0.01N is used for sequestering. For aluminum concentrations less than 10 Kg/l. and an aluminum-iron ratio of 1:100 or less, a relative error not exceeding 10% is reached only by increasing the concentration of EDTA to 0.1N. Rodriguez Cid ( I 7C) compared 1,lO-phenanthroline and 4,7-diphenyl-l,lO-phenanthrolinefor determining iron spectrophotometrically in public water supplies. The latter reagent is preferable because most other elements do not interfere. Both dissolved and total iron can be determined. A spectrophotometric method for the determination of iron in raw and treated waters based on the chelation of iron was develwith 2,4,6-tri(2-pyridyl)-1,3,5-triazine(TPTZ) oped by Dougan and Wilson (2C). Iron is reduced to the ferrous state by hydroxylamine hydrochloride in an acetate buffer solution and the TPTZ-iron chelate measured a t 595 nm. No interferences were found. The method is useful for the range from 0 to 1 mg/l. of iron with a standard deviation of 0.003 to 0.008 mg/l. Stephens, Felkel, and Spinelli (21C) used propylene carbonate (4-methyl-l,3-dioxolane%one) to simultaneously extract the TPTZ chelate of iron(11) and the neocuproine chelate of copper(1). The extracted iron(I1)-TPTZ chelate is measured spectrophotometrically at 596 nm. Copper does not interfere at this wavelength. The relative standard deviation over the range of 5.93 to 59.3 pg iron for six determinations is 2.58%. Results of analyses of sea water and tap water are reported. Dzysyuk and Ivanova (3C) recommended evaporation of power plant water in the presence of hydrochloric acid prior to the determination of iron by the sulfosalicylate method. 336R

ANALYTICAL CHEMISTRY, VOL. 47,

NO. 5,

Korenaga, Motomizu, and Toei (IOC) studied a number of nitrosophenols and nitrosonaphthols as reagents for ternary complex formation with iron(I1) and Rhodamine B. 2Nitroso-4-chlorophenol is the best. The complex is extracted into benzene and measured spectrophotometrically at 558 nm. The method was applied to the determination of iron on potable and river waters. Beer’s law is obeyed over the range of 0 to 1 X 10-5M iron(I1). Hayashi, Sasaki, and Ito (7C) determined iron in natural water spectrophotometrically with pyrrolidinecarbodithioic acid. Beer’s law is obeyed for 0 to 6 wg/ml at 360 nm and 0 to 8 pg/ml a t 515 or 600 nm. Details of the procedure are given. The determination of 0.5 to 50 pg/l. of iron in distilled water and waters of electric power plants based on the catalytic effect of iron(II1) on the oxidation of o-toluidine by potassium iodate a t pH 4 to 6 in the presence of 2,2’-bipyridine is reported by Rychkova and Rychkov (18C). A violet color is formed which shows maximum absorbance at 540 nm. Manganese(I1 and VII) greater than 30 pgh. and chromium(II1) greater than 100 pg/l. interfere. Dolmanova, Rychkova, and Peshkova ( I C ) used p-phenetidine in place of o-toluidine to catalytically determine iron in boiler feed water in the range of 0.5 to 10 pg. Only manganese in equal amounts interferes. Seitz and Hercules (19C) determined iron in water by measuring iron(I1)-catalyzed light emission from luminol oxidation by oxygen. Iron(I1) is the only common metal ion to catalyze the reaction in the presence of oxygen alone. Beer’s law is followed up to 50 pgll. The detection limit is 0.005 pgA. High concentrations of organic ligands reduce the intensity of light catalyzed by iron(I1) but do not affect linearity of response. Excess quantities of copper(II), manganese(II), cobalt(II), chromium(III), and nickel(I1) reduce the light intensity and affect linearity. Chemiluminescence analysis for total iron in natural water samples agreed with values obtained by atomic absorption. Hiiro, Tanaka, and Sawada (8C) used atomic absorption spectrophotometry to determine ppb amounts of iron in water. Iron is chelated and extracted with oxine-methyl isobutyl ketone (MIBK). Phosphate interferes but the interference is eliminated if a 0.1M oxine-MIBK solution is used. Linear analytical curves are obtained in the range of 100 to 500 ppb. Florkowski and Holynska (4C) applied nondispersive Xray fluorescence to the analysis of suspended iron in water. The limit of detection is 60 ppb of the metal in the water. A bicrystal scintillation spectrometer based on by-coincidence of 59Fe is described by Glazov (6C) for the determination of iron in water using activation analysis. Matsui (13C) described an automated spectrophotometric method for the determination of manganese(I1). The manganese is separated from other metals by ion exchange using a mixture of ammonium chloride and thiocyanate as the eluant. Zincon is then added to the automated system, and the color formed is measured at 690 nm. The method was applied to the determination of manganese in river water. Smith (20C) used an ion-exchange technique for the concentration of manganese from sea water prior to its determination by atomic absorption spectrophotometry. In a test, 99% of the j4Mn added to sea water was recovered in the eluate, 0.1 to 0.2% remained on the resin, and less than 1%remained in the sample solution. Hirose, Kobori, and Ishii (9C) described a neutron activation method using ionexchange preconcentration for the determination of manganese in sea water. The chemical yield of manganese is greater than 98%. The minimum determinable and detectable masses are approximately 0.06 wg/1. and 0.012 pgh., respectively. Maly and Fadrus (12C) reported that oxidation products

APRIL 1975

of manganese react with o-tolidine to produce a yellow color, which can be utilized for the photometric determination of manganese. Divalent manganese is first oxidized to higher valence forms with atmospheric oxygen in alkaline solution in the presence of magnesium and iron(II1) salts. The probable error of determination is f 1 2 Mgh. The method was tested on a series of surface and waste water samples. Iron(I1) interferes at concentrations greater than 40 mg/l. A chemiluminescent method based on the catalytic action of manganese in the oxidation of luminol by hydrogen peroxide was used by Nabivanets and Turba (14C) to determine manganese in water. Iron(II1) interference is eliminated with o-phenanthroline and sodium citrate is used to eliminate interferences by other metal ions. Pepin et al. (I6C) determined manganese in mineral water spectrographically using the dry residue. Pankow and Janauer (15C) developed a new procedure for the preconcentration of chromate from aqueous samples. One-liter samples, acidified to pH 5 are passed through an ion-exchange resin (AGl-X4) in ascending flow, so that the chromate is adsorbed in a narrow zone at the lower end. The chromate is eluted rapidly with small volumes of an acidic reductant solution producing very high concentration factors. The proposed procedure in conjunction with atomic absorption spectrophotometry has made possible the determination of 0.1 ppb chromate with a precision of f 2 0 % or better. Gilbert and Clay ( 5 C ) described a rapid atomic absorption spectrophotometric method for the determination of chromium in sea water. The chromium from filtered samples is oxidized with permanganate and extracted with APDC into MIBK. Non-filterable solids are extracted with 12M hydrochloric acid and analyzed. Detection limits for the methods are 0.05 Fg/l. in the dissolved phase and 0.06 Fg/l. in the particulate phase. Tessari and Torsi (22C) determined ppb amounts of chromium in water, sea water, and other matrices by atomic absorption spectrophotometry using a carbon rod flameless atomizer. The influence of the most common anions and cations is described.

COPPER, ZINC, LEAD, CADMIUM, NICKEL, COBALT, A N D T I N Muzzarelli and Rocchetti ( 3 5 0 ) determined copper in sea water by atomic absorption spectrophotometry with a graphite atomizer after concentration and elution on chitosan. Either 1%1,lO-phenanthroline or 1 M sulfuric acid will elute the copper. The standard deviation of a sea water sample containing 6.06 Mg per liter of cadmium wqs f0.56 kg/l. Kerfoot and Vaccaro ( 2 3 0 ) used activated carbon to extract copper from sea water. The copper is then eluted with acid and determined by atomic absorption. The authors reported that the results compare well with organic extraction methods, although the accuracy is somewhat reduced. Fairless and Bard ( 1 3 0 )described a hanging mercury drop electrodeposition technique for carbon filament flameless atomic absorption analysis to determine copper in sea water. The detection limit for this technique with the electrode configuration described with a 2.5-ml sample and 30-min electrolysis is 0.2 Fg per liter of copper. Traces of copper in potable water were determined by Novosel and Buchanan ( 3 8 0 ) by square-wave polarography. The limit of detection is 2 ppb Cu. The reproducibility is f0.13 ppb. To determine the copper content of water samples using standard addition techniques with an ion-selective electrode, Smith and Manahan ( 5 0 0 ) used a complexing antioxidant buffer. With the method, copper in tap water was

determined at concentrations down to 9 FgA. Recovery was investigated with samples containing 3.3 to 46.8 Mg per liter of copper initially. For 6 samples spiked with 9.0 gg/l., the average recovery was 102.9% with a standard deviation of 7.5%. Jasinski, Trachtenberg, and Andrychuk ( 2 2 0 ) reported that with proper precautions in sample handling and measurement, the ionic copper concentration of sea water can be monitored with ion-selective electrodes. A technique tested by Virmani and Zeller ( 5 5 0 ) makes possible the determination of copper in sea water in ranges as low as 0.1 ppb. The system makes use of electron spin resonance combined with concentration by chelation and solvent extraction. Nabivanets et al. ( 3 6 0 )used a new selective reagent, pofor the extassium dodecahydro-1,2-dicarbaundecaborate, traction-photometric determination of copper in water and other materials. The copper complex can be extracted with either tributyl phosphate or methyl ethyl ketone. Among other elements tested, only silver reacts with the reagent. Stephens, Felkel, and Spinelli ( 5 1 0 ) reported that propylene carbonate simultaneously extracts the neocuproinecopper chelate and the TPTZ-iron chelate (see previous section for the measurement of the iron). The copper chelate is measured at 458 nm. At this wavelength, the iron chelate exhibits an absorbance that is 0.123 times its absorbance at 596 nm; therefore, the correction for the effect of iron on the determination of copper is straightforward. Results of analyses of sea water and tap water are reported. A modified phenylcarbazone photometric method was used by Kuznetsov ( 3 1 0 )to determine copper in water. Dolmanova, Poddubienko, and Peshkova ( 1 0 0 ) determined copper in sea water by the catalytic oxidation of hydroquinone with hydrogen peroxide in the presence of Mg per ml of copcup’-dipyridyl. The sensitivity is 2 X per. Only 1000-fold amounts of iron(I1) interfere by accelerating the rate of reaction. Lieberman and Zirino ( 3 2 0 ) described an anodic stripping voltammetric method which uses a tubular mercury graphite electrode to determine zinc in flowing solutions of sea water. Fabrication of the electrode and a new method of applying and maintaining a consistently active thin film on a graphite electrode are described. Measurements are reproducible with a relative standard deviation of f9.5% at the 3 X 10-8M zinc level. They reported that the system is more sensitive than a comparable static system. Cirilli and Massari ( 6 0 )reported that the determination of zinc in water and waste water by atomic absorption and the dithizone method is affected by losses of 1 and 3% and increments of up to 1.5 and 5%. They devised a spectrophotometric method involving wet mineralization, cyanide complexation, and color reaction with zincon with an accuracy of 2% or better. Matsui ( 3 3 0 )described an automated zincon method for the determination of zinc in water which uses ion-exchange chromatography. In the proposed method, 2.0 to 15.0 Fg of zinc can be determined without interference and with a maximum error of 3%. The application of the GeMSAEC Fast Analyzer to conventional spectrophotometric methodology has been studied by Goldstein, Maddox, and Kelley (170). Because the analyzer is coupled to a computer, large numbers of measurements can be rapidly averaged and relative standard deviations as small as 0.2% have been obtained. A method for the determination of zinc from 0.2 to 1 ppm in natural and treated water using 4-(2-pyridylazo)resorcinol was adapted to the analyzer. The relative standard deviation is 0.3 to 3%. Watanabe and Kawagaki (560) determined zinc in tap water and ground water fluorometrically. Zinc is complexed

ANALYTICAL CHEMISTRY, VOL. 47, NO. 5 , APRIL 1975

337R

with thiooxine and extracted a t a pH greater than 3.5 with either chloroform or MIBK. Most other metals either do not interfere or are masked with potassium cyanide. Florkowski and Holynska ( 1 5 0 ) used non-dispersive Xray fluorescence to determine particulate zinc in water. The limit of detection is 60 ppb. Radioisotope dilution methods for the determination of zinc in surface water and sea water were reported by Kusaka and Ozaki (300) and Petrov (400), respectively. Details of the procedures are given. Shigematsu et al. ( 4 8 0 ) determined lead by atomic absorption spectrophotometry using a carbon tube flameless atomizer. The variables affecting sensitivity and reproducibility such as the inside diameter of the tube, the inert gas and its flow rate, and sample injection volume, as well as interference of diverse ions were investigated. The detection limit is 6.5 X 10-l' g of lead with a relative standard deviation of 2.8%. Because several cations interfered, lead was determined after chelation and extraction. Aldous, Mitchell, and Ryan ( 2 0 ) used a computer-controlled atomic absorption spectrophotometer for measurement of transient atom populations, and applied it to the determination of lead in potable water using a Delves cup. A review with six references on the determination of lead by inverse polarography was prepared by Armeanu and Hornar ( 3 0 ) . Fujikawa ( 1 6 0 ) investigated stripping voltammetry using a dropping mercury electrode and applied it to the determination of lead in municipal waters. Kinard and Propst (240) determined ppb concentrations of lead in rain and surface waters by cathodic stripping voltammetry with calibration from 0 to 100 ppb, the standard deviation for a single determination is f1.8 ppb. Four papers on the determination of cadmium by flameless atomic absorption spectrophotometry were published. Shigematsu, Matsui, and Fujino (470), and Yasuda and Kakiyama (580) used a carbon tube atomizer. Robinson et al. (440) used a radiofrequency generator which heated up a carbon bed to approximately 1400 OC. Detection limits of 1X g of cadmium were reached. Van Loon, Lichwa, and Ruttan (540) evaluated both flame and flameless atomization methods. Hiiro, Kawahara, and Tanaka (190) used ion-exchange enrichment prior to conventional flame atomic absorption spectrophotometry to determine ppb levels of cadmium in sea water. Owa, Hiiro, and Tanaka (390) combined coprecipitation and chelation-extraction (diethyldithiocarbamate-MIBK) to determine cadmium in sea water by atomic absorption spectrophotometry. Doolan and Smythe (110) reported that addition of a large amount of zinc(I1) to a water sample before extraction by 2-mercaptobenzothiazole into n-butyl acetate brings about almost total extraction of cadmium and allows determinations of concentrations down to at least 0.02 ng/ml. Utsumi, Okutani, and Ozawa (530) used atomic absorption spectrophotometry to determine cadmium between 2 and 40 ppb in fresh water. The method is based on the extraction into ethyl acetate of an ion-pair formed between cadmium iodide complex anion and zephiramine. A stripping polarographic method for the determination of cadmium in mine waters was reported by Komatsu and Kakiyama (260). The wave height is linearly proportioned from 0,001 to 0.01 ppm. The standard deviation is 5% for 0.08 ppm. Results agreed well with those obtained by atomic absorption spectrophotometry. Korkisch and Dimitriadis (280) separated cadmium from other trace metals by ion-exchange using Dowex 1-X8 anion exchanger. After elution with 2M nitric acid, the cadmium is determined colorimetrically with dithizone. 338R

King, Rodriguez, and Wai (250) studied the magnitude as well as the mechanism for the loss of cadmium from water samples stored in various containers. Losses of cadmium in solutions of different concentration and pH were measured with respect to time. At pH less than 7 , loss in glass containers is not detectable. In various plastic bottles losses were less than 3% from solutions at pH 3 to 10 after 2 weeks. Prokhorova et al. (420) described-a polarographic method to determine nickel in sea water. The nickel is first concentrated by extraction of the nickel dimethylglyoximate complex. At a constant dimethylglyoxime concentration of 5 X 10-4M the wave height is proportional to nickel conto 6 X 10-5M. A further incentrations between 3 X crease in the sensitivity can be obtained by using oscillographic polarography, by which differential polarograms can be recorded. Cobalt and copper in 100-fold excess do not interfere. Toei and Motomizu (520) reported that among 25 nitrosophenols and nitrosonaphthols, 2-nitroso-5-dimethylaminophenol and 2-nitroso-5-diethylaminophenol were the most advantageous for the photometric determination of cobalt in sea water and other materials. Motomizu ( 3 4 0 ) described a spectrophotometric procedure for the determination of cobalt in sea water using the latter compound described above. The cobalt complex is extracted into 1,2-dichloroethane. Interferences are prevented by masking or by stripping from the organic phase. The method is applicable over the range of 0 to 0.24 pg per liter of cobalt when a 1-or 2-liter sample is used. The relative standard deviation is 4% for 0.15 pg/L Bilikova ( 4 0 ) described the use of p-nitrosoa-naphthol for the spectrophotometric determination of cobalt in water. The cobalt complex is extracted with toluene and measured a t 535 nm. Most other substances in 100-fold excess do not interfere. Korkisch and Dimitriadis (270) described two methods for the determination of cobalt in natural waters. In the first, the cobalt in the sample is separated from other ions by absorption as the cobalt thiocyanate complex on a strongly basic anion-exchanger. The cobalt is then eluted with HC1 and determined photometrically with nitroso-Rsalt. In the second method (for very dirty samples), the filtered sample is taken through a multi-step evaporation procedure before proceeding as above. A pulse polarographic method is described by Harvey and Dutton ( 1 8 0 ) for the determination of nanogram quantities of cobalt in a liter sample of sea water after preconcentration with sub-mg quantities of manganese dioxide formed by the oxidation of manganese(I1) in a photochemical reactor. The cobalt is measured as the dimethylglyoximate after dissolving the manganese dioxide deposit adhering to the quartz jacket surrounding the UV lamp. The detection limit is about 0.6 pg per liter of cobalt. Ross, Hansen, and Scribner ( 4 6 0 ) determined traces of cobalt in water by chelation and gas chromatography with electron capture detection. Supporting electrolytes for the determination of tin in water by thin film anodic stripping voltammetry was studied by Florence and Farrar (140). Since lead produces peaks at potentials almost identical to tin, a distillation step is first used to separate the tin from the lead. Portretnyi, Malyuta, and Chuiko ( 4 1 0 ) reported that trace amounts of tin can be concentrated from natural water by precipitation with Mg(0H)z followed by tin accumulation on a graphite electrode using stripping analysis. Lead and copper interfere and must first be removed. The sensitivity is 2 X 10-11 g per ml of tin. A number of publications discuss multiple determination


of metals in water by various polarographic techniques. Afghan and Goulden (10) reported on the simultaneous determination of Cu, Pb, Cd, Zn, and Co a t approximately l x 1O-SM concentration by twin-cell oscillographic directcurrent polarography. Ebner, Gams, and Ottendorfer ( 1 2 0 ) discussed ac polarography for the determination of Cu, Ni, Zn, and Cd, and inverse polarography for the determination of Pb. Copeland et al. ( 8 0 ) used differential pulse stripping voltammetry with thin film electrodes for the determination of lead and cadmium. Chau and Lum-ShueChan ( 5 0 ) applied differential pulse anodic stripping voltammetry to differentiate and determine the labile and strongly bound forms of Zn, Cd, Pb, and Cu in lake water without preconcentration. Other anodic stripping polarographic techniques have been reported by Clem, Litton, and Ornelas ( 7 0 ) ,Hume and Carter (210), Rojahn ( 4 5 0 ) , and Yamazaki ( 5 7 0 ) .A method employing an ion exchange chromatograph and an atomic absorption spectrophotometer was developed by Kubota et al. ( 2 9 0 ) for the determination of Cd, Pb, and Zn in river water and industrial waste water. Nakagawa ( 3 7 0 ) used atomic absorption spectrophotometry to determine Zn, Pb, and Cd in hot spring waters. Holroyd and Snodin ( 2 0 0 ) determined lead and cadmium in tap water and rain by atomic absorption spectrophotometry after chelation-extraction using APDC and 2heptanone. Shiraishi et al. (490) investigated the distribution of MIBK in various salt solutions while determining the diethyldithiocarbamate chelates of cadmium and lead by atomic absorption spectrophotometry. Ritchie ( 4 3 0 ) combined ion-exchange and chelation-extraction for the determination of Pb, Zn, Ag, Ni, and Cd in geothermal waters by atomic absorption spectrophotometry. Dolinsek and Stupar ( 9 0 ) used a flameless atomization technique to determine Pb, Cu, and Cd in water by atomic absorption. The detection limits for Pb, Cu, and Cd are 0.45, 1.7, and 0.1 ng/ml, respectively. The addition of EDTA solution to the samples enhanced the sensitivity, particularly for lead.

MERCURY, SILVER, AND GOLD Rosain and Wai (28E)studied the rate of loss of mercury from distilled and natural waters when stored in polyethylene, poly(viny1 chloride), and soft glass containers. Losses of mercury at different pH values were monitored by flameless atomic absorption for a total of 17 days. Solutions acidified to pH 0.5 with nitric acid curtailed mercury loss substantially. Newton and Ellis (23E) also investigated the loss of mercury(I1) using 203Hg(II)as a tracer. Loss was severe only a t mercury concentrations of 0.2 ppm or lower. Mercury was stable at all levels in concentrated nitric acid. Glass and plastic containers differ in their ability to retain mercury in solution. Carr and Wilkniss (2E) reported on the short term storage of mercury in natural waters. Use of carrier-free lg7Hg and improved flameless atomic absorption techniques show negligible losses to sample containers after 8-day storage a t pH 1. Feldman (7E) used nitric acid, sulfuric acid plus potassium permanganate, or potassium dichromate to preserve dilute mercury solutions (0.1-10 ng/ml). Solutions stored in polyethylene and treated with 5% "03 plus 0.05% dichromate stayed a t full strength for a t least 10 days, while those stored in glass and treated with 5% nitric acid plus 0.01% dichromate, stayed at full strength for as long as 15 months. Many flameless atomic absorption methods for mercury based on modifications of the method of Hatch and Ott have been reported during the past two years. Olafsson (26E) amalgamated the vaporized mercury onto gold using a stream of argon prior to analysis. Adsorption colloid flotation was used by Voyce and Zeitlin (32E) to separate

ionic mercury from sea water quantitatively a t levels as low as 0.02 pg/l. with use of a cadmium sulfide collector and octadecyltrimethyl ammonium chloride as the surfactant. Jonasson, Lynch, and Trip (13E), Harsanyi et al. (IOE), and Topping and Pirie (30E)also reported flameless atomic absorption methods for inorganic mercury in water using stannous chloride to produce the mercury vapor. An enrichment method for preconcentration of mercury from sea water is discussed by Harsanyi, Polos, and Pungor (11E). The mercury is carried by an air stream into a small volume of permanganate-sulfuric acid solution after treatment of the sample with tin(I1). Mercury is then determined by the usual cold-vapor technique. The limit of detection is 0.008 ng per ml of mercury. Various techniques are reported by Alberts et al. ( I E ) , Kamada et al. ( 1 4 E ) , Marino Aguiar (21E),and Dujmovic and Winkler (5E) for determining both inorganic and organic mercury by the flameless method. Details of the digestion procedures are given. A highly efficient purging system, which is simple and inexpensive, and increases sensitivity while reducing analysis time is described by Gilbert and Hume ( 8 E ) for determining mercury by flameless atomic absorption. A wet digestion was developed by Ke and Thibert (16E) to prepare water and biological samples for a kinetic determination of 0.05 to 2.0 mg per ml of mercury using an iodide-catalyzed reaction between cesium(1V) and arsenite(II1). A mercury-free control is prepared using a selective ion exchange material. Elly (6E) determined mercury by extraction of mercury ion with a chloroform solution of dithizone in 1N sulfuric acid. Lead, cadmium, zinc, nickel, cobalt, iron, and copper do not interfere. The addition of acetic acid stabilizes the complex for a t least 1hour. Beer's law is obeyed over a concentration range of 0.002 to 0.040 mg per liter of mercury. The relative standard deviation is 3%. Mazalovic and Hafizovic (22E)reported on a dithizonecolorimetric method for the determination of mercury in drinking water. Silver, copper, zinc, cobalt, and bismuth interfere. The detection limit is 1 ppb. Klisenko and Shmigidina (17E) determined mercury as the dithizonate in chloroform by chromatography on silica gel KSK by comparison to reference standards. Organomercury compounds are initially separated by chloroform extraction. Holzbecher and Ryan (12E) described a fluorometric determination of mercury(I1) in water based on its oxidative reaction with thiamine to yield the highly fluorescent thiochrome. For best results, the pH of the reaction mixture must be between 7 and 8 and the salt concentration should not exceed 0.02M. The fluorescence intensity is linear over a range of 10 to 200 ng/ml. Cyanine, iodide, sulfide, and EDTA interfere by decreasing the fluorescence. Knight and Pyzyna (18E) determined mercury in industrial water at submicrogram levels by emission spectroscopy. Mercury is concentrated by deposition from solution onto silver powder. Direct gas chromatographic separation and detection of dialkylmercury compounds with a mercury-specific detector was studied by Dressman ( 4 E ) and Longbottom and Dressman (19E). River water samples are analyzed for dialkylmercury compounds a t the nanogram level without conversion to chloride salts, using electron capture detection. The separated compounds are combusted in a flame ionization detector and the resultant free mercury passed into a cold vapor mercury detector. Longbottom, Dressman, and Lichtenberg (20E) also reported another gaschromatographic method for determining methylmercury in water and other materials. Methylmercury is extracted as the chloride salt and then treated with a common clean-


* 339R

up procedure that converts methylmercury to the iodide salt for electron capture analysis. Methods for controlling cdntaminants and interferences are discussed for all phases of the method. The average recovery of mercury is 88.5%. Chau and Saitoh (3E) described a method for determining methylmercury compounds in lake water. The compounds are extracted by benzene in a continuous extractor followed by selective extraction with 1-cysteine. I t is then converted to a chloride and back-extracted into benzene for gas chromatographic determination using an electron capture detector. The identification of methylmercury chloride at the one-ppb level by gas chromatography-mass spectrometry is reported by Ohkoshi, Takahashi, and Sato (25E). Methylmercury is extracted with benzene from a 500-ml sample of water. The benzene is then evaporated to a small volume before analysis. Toth (3IE) determined traces of mercury in natural waters by deposition of mercury on palladium black, activation of the palladium and mercury, and separation of radioactive mercury from the palladium and other isotopes formed by means of isotope exchange. Kawabuchi and Riley (15E) developed a neutron activation procedure for the determination of silver in sea water. The element is preconcentrated by anion-exchange (Deacidite FF-1P resin) and submitted to irradiation for 24 hr or more with a neutron flux of greater than 3 X neutron per cm2 second. The silver-ll0m is then separated from other radionuclides by conventional radiochemical separation. The method gives a coefficient of variation of &lo% a t 40 ng per liter of silver. A kinetic method for the determination of gold in water was developed by Pilipenko and Pavlova (27E).The method is based on the catalytic action of gold in the oxidation of iron(I1) with silver ion in 0.1N hydrochloric or sulfuric acid. The detection limit in pure solutions is 3 X pg gold. Palladium fluoride, and thiocyanate a t a ratio of 1:lO interfere. Most other substances do not interfere. Glukhov, Larionova, and Gil’bert (9E)used partition chromatography to separate gold in natural waters from complex mixtures of 21 cations. Only palladium is absorbed together with gold. Nikanorov and Kist (24E) determined gold in natural waters by neutron activation. After activation, gold carrier is added and dissolved, and the solution passed through anion exchange resin to separate the gold. The method is sensitive to 10-96 gold with a relative standard deviation of 8 to 15%. A spectrographic procedure for determining gold in sea (29E). water was reported by Sharma -

MOLYBDENUM, VANADIUM, BISMUTH, URANIUM, THORIUM, A N D RARE EARTHS Muzzarelli and Roccheti (13F) reported that there is a strong interaction between molybdenum and chitosan or p-aminobenzylcellulose in thiocyanate solutions and in sea water. By combining the sensitivity of the graphite-furnace atomic absorption spectrophotometer with the efficiency of the selective collection of molybdenum with polymers a t pH 2.5, it is possible to determine molybdenum in as little as 50 ml of sea water in the microgram per liter range. Kobrova ( 8 F ) described a spectrophotometric method for determining as little as 0.2 pg of molybdenum in water. Organic compounds are removed by oxidation with potassium permanganate and the molybdenum is coprecipitated with hydrated manganese dioxide. Molybdenum is then complexed with toluene-3,4-dithiol, extracted into chloroform, and the complex measured at 665 nm. The reaction between hydroquinone and iodide catalyzed in the presence of potassium oxalate by molybdenum(V1) was studied 340R

by Klyachko and Petukhova (7F). Optimal conditions for determining 1 X lo-* to 1 X pg per ml of molybdenum in tap water were reported. Nishimura et al. (15F) modified the 4-(2-pyridylazo)resorcinol (PAR) method for the direct chelation-extraction determination of vanadium in sea water. Potassium cyanide and CyDTA are added to mask interfering cations, and turbidity in the chloroform layer is eliminated by washing with sodium chloride solution. The sensitivity is 0.025 pg per liter of vanadium for 0.001 absorbance unit. The relative standard deviation at the 1- and 3-pg per liter level is 8 and 3%, respectively. Kiriyama and Kuroda (6F) utilized a Dowex 1-thiocyanate system to concentrate vanadium from sea water. Vanadium is then determined colorimetrically with 4-(2-pyridylazo)resorcinol. Kreingol’d, Panteleimonova, and Poponova (12F) determined vanadium in pure water catalytically. The method is based on the reaction of meturin and potassium bromate a t pH 2 in the presence of traces of vanadium. A method based on anodic stripping voltammetry a t the mercury-coated graphite electrode was developed by Gilbert and Hume (3F) for the direct determination of bismuth in sea water. By use of the standard addition technique, satisfactory results were obtained for sea water samples in the range of 0.02-0.09 pg/kg. Florence (2F) also used anodic stripping voltammetry with a polished glassy carbon electrode mercury-plated in situ to determine bismuth in sea water. Skrdlik, Havel, and Sommer (17F) described a spectrophotometric method for the determination of uranium using chromotropic acid. The absorbance is measured a t either 410, 460, or 500 nm. Most interfering cations are masked. Beer’s law is obeyed up to 100 pg per ml of U0z2+. Ryabinin and Lazareva (16F)modified the colorimetric arsenazo I11 method to determine uranium in sea water. Uranium is separated from iron(II1) by 2-stage carbonate leaching and photometry is done from 4-6M hydrochloric acid with preliminary reduction of uranium(V1) to uranium(1V) with zinc. Korkisch and Kick (IOF) concentrated uranium from sea water on Dowex 1-X8 anion exchange resin prior to fluorometric or spectrophotometric measurement. In an earlier publication Korkisch and Steffan ( I I F ) described another anion exchange (Dowex l-X8) separation of uranium from water and other geological materials. The eluted uranium is determined fluorometrically or titrimetrically. Danielsson et al. ( I F ) described a fluorometric determination of uranium in natural waters. The limit of detection is 0.3 ppm. Ion-exchange is used to preconcentrate the uranium by a factor of 22 and to separate it from quenching ions in the sample. Horrocks (4F) measured uranium in water in amounts equal to or greater than 0.1 pg/ml by liquid scintillation alpha counting. An emulsifier system is used to incorporate 5 ml of aqueous solution in a 15-ml counting solution with 100% counting efficiency for the a particles from the 234U and 238U radionuclides. Use of a multichannel analyzer allows corrections for the presence of short-lived /Iemitters in the uranium decay chain. Steinnes (18F) reported that a neutron activation method based on 23.5 minute 239U using solvent extraction with tri-n-butyl phosphate as a selective separation step is sensitive and precise for the determination of uranium in fresh waters. Korkisch and Dimitriadis ( 9 F ) used Dowex 1-X8 anionic exchange resin to concentrate thorium in natural waters. The thorium is eluted with 6M hydrochloric acid and determined spectrophotometrically by the arsenazo I11 method.


Kirillov, Makarenko, and Vlasov (5F) described a spectrophotometric method to determine yttrium subgroup elements in mineral waters. Interfering elements are removed by chelation-extraction and the yttrium reacted with pyrocatechol and the absorbance measured at 610 nm. Nevoral (14F) used cation exchange (Dowex 50W-X8) to concentrate and separate rare earth metals in mineral waters. The major cations are eluted first with 1.6N hydrochloric acid and then the rare earth metals are eluted with 6 N hydrochloric acid. The rare earth metals are then determined photometrically with xylenol orange in the presence of cetylpyridinium bromide at pH 7.9.

BORON, SELENIUM, ARSENIC, ANTIMONY, PHOSPHORUS, A N D SILICA A method was developed by Barboliani Piccardi ( 4 G ) to avoid nitrite interference in the spectrophotometric-curcumin method for boron in water. Nitrite is decomposed with sulfamic acid before formation of the curcumin complex. Bassett and Matthews (5G) determined boron in drinking, sea, and river waters, and in sewage spectrophotometrically by complexing boron with salicylate and forming an ionassociated complex with ferroin. The complex is extracted with chloroform and measured a t 516 nm. Procedures to eliminate interferences are reported. Ternary compounds of boron with salicylic acid and some dyes were studied by Vasilevskaya (4%') for determining boron in waters. Details of the procedure are given. The relative error of the determination of 20 mg per liter of boron in water was f8.796. Monnier and Marcantonatos ( 3 4 G ) determined submicro traces of boron by UV fluorometry using 2-hydroxy-4-methoxy-4'-chlorobenzophenone(HMCB). An automated fluorometric method for the determination of boron in natural waters based on the reaction of 4'-chloro2-hydroxy-4-methoxybenzophenone (CHMB) with boron to produce fluorescent species in a 90% sulfuric acid medium is described by Afghan, Goulden, and Ryan ( I C ) . The method is specific for boron and is capable of measuring different chemical forms of boron such as boric acid, and sodium perborate and the tetraphenyl boron ion. The detection limit is 1 pg per liter of boron. Marcantonatos, Gamba, and Monnier ( 3 2 G ) determined nanogram amounts of boron in sea water based on measurement of the phosphorescence emitted by a boric acid-dibenzoylmethane complex in a sulfuric acid-diethyl ether glassy medium. The effects of tungsten and molybdenum on the determination are discussed. A method free from common interferences and capable of detecting 1 ppb of selenium in clean water was developed by Rankin ( 4 0 G ) . Inorganic selenium is oxidized to selenate with hydrogen peroxide. The selenate is then reduced to selenite with hydrochloric acid, and the selenite is reacted with 2,3-diaminonaphthalene to form an extractable piaselenole which is determined fluorometrically. Hiraki et al. (20G) used a similar procedure after concentrating selenium from 5 liters of sea water by coprecipitation with ferric hydroxide. Selenium is then separated from iron and other cations by ion exchange using Dowex 50W-X8 in the hydrogen form prior to fluorometric measurement using 2,3-diaminonaphthalene. Bowling, Dean, and Goldstein (6G) reported that a rapid ion exchange separation converts the methylene blue spot test for selenium into a selective and sensitive method for the quantitative photometric determination of selenium in water. Shimoishi (45G) described a direct gas chromatographic determination of selenium in sea water, with 4-nitro-o-phenylenediamine using electron-capture detection. Approxi-

mately 0.002 pg of selenium in 1 ml of organic extract can be detected. Lansford, McPherson, and Fishman (27G) described a hydride generation atomic absorption procedure to determine selenium in water. Organic selenium compounds, if present, are first decomposed by digestion with potassium permanganate in hot acid solution. The solution is then made basic, evaporated to dryness, and the selenate reduced to selenite with hydrochloric acid. Finally, the selenium is liberated from 6M hydrochloric acid with stannous chloride and the selenium hydride measured. Two micrograms per liter of selenium can be detected using 100 ml of water. Baird, Pourian, and Gabrielian ( 3 G ) determined selenium in waste water by a flameless atomic absorption spectrophotometric method using a carbon rod attachment. The main advantage is the absence of the usual high levels of flame background normally responsible for the decrease in sensitivity in selenium detection. Digestion with nitric and perchloric acids is used to oxidize organic materials and solubilize the selenium before injection. The absolute detection limits for selenium standards and waste water samples is 26 and 33 picograms, respectively. In the monitoring of water supplies for arsenic and selenium, modifications of classical methods for converting organic and inorganic arsenic and selenium compounds to their respective hydrides, and measurement of the hydrides by atomic absorption spectrophotometry are discussed by Caldwell, Lishka, and McFarren (9C). The working range for both elements is 2 to 20 pg/l. Yamamoto et al. (50G) used zinc powder tablets together with potassium iodide and stannous chloride in the evolution of arsine and measurement of arsenic by atomic absorption spectrophotometry with an argon-hydrogen flame. The analytical curve is linear to 50 ppb. The interference of diverse ions was also studied and tolerable levels are given. Reinke (42G) reported that both the silver diethyldithiocarbamate photometric method and the flameless atomic absorption spectrophotometric method using a graphite atomizer are suitable for the determination of arsenic in water and waste water. Details of the atomic absorption procedure are given. Tam (46G) determined arsenic in water by flameless atomic absorption spectrophotometry with a carbon rod atomizer. Arsenic is extracted with diethylammonium diethyldithiocarbamate in carbon tetrachloride prior to atomization. Arsenate, arsenite, and any organoarsenic compounds soluble in carbon tetrachloride will be determined. For total arsenic, ultraviolet photooxidation is used. No matrix interference is observed. Precision is f 0 . 4 pg/l. at 3.1 pg/l. and the detection limit is 1 Pdl. An indirect atomic absorption spectrophotometric method to determine ppm levels of arsenic in water was developed by Yamamoto et al. (49G). Arsenic(II1) is oxidized to arsenic(V) by iodine, then arsenomolybdic acid is formed and extracted into MIBK from 0.2 to 1.6M hydrochloric acid. Excess molybdate is scrubbed from the organic phase and molybdenum in the heteropoly acid determined. Silicate and phosphate interfere. Kobrova ( 2 5 G ) used amperometric titration to determine microgram amounts of arsenic in waters. Arsenic(II1) is titrated with bromate ion using a platinum rotating wire electrode with an inserting voltage. In 100 ml of sample, 5 pg of arsenic trioxide can be determined. Methods to isolate traces of arsenic by coprecipitation procedures were also investigated. Ray and Johnson ( 4 1 G ) described a neutron activation procedure to determine arsenic in the low ppb range in freshly collected natural waters. Arsenic(V) is reduced to


341 R

arsenic(II1) with ascorbic acid. The arsenic(II1) is then cocrystallized with thionalide and irradiated. The 76Asactivity is then measured by a-ray spectroscopy. Byrne and Vakselj (8G) determined arsenic in water by neutron activation. Following activation, arsenic is extracted as the iodide and the 76Asis measured. Thiel and Carpentier (47G) determined as little as 0.5 ppb arsenic in a 260-ml volume of natural water photometrically with silver diethyldithiocarbamate. Arsenic is first concentrated from the water sample by coprecipitation with ferric hydroxide. Kopp (26G) reported that the substitution of 1-ephedrine in chloroform for pyridine as the solvent for the silver diethyldithiocarbamate reagent eliminates the disagreeable odor. No loss in sensitivity, accuracy, or precision was observed. The determination of arsenic(II1) in natural waters based on a simple modification of the silver diethyldithiocarbamate standard method for inorganic arsenic was developed by Clement and Faust (12G). The stannous chloride-potassium step is eliminated and dimethylformamide is added to block reduction of arsenic(V) without preventing arsine generation from arsenic(II1). In practice, the technique was found to detect an average of 96% of the arsenic(II1) present. Farkas et al. (17G) stated that the determination of the amount of arsenic in samples of- drinking water would be facilitated if the arsenic could be concentrated into a smaller volume. The use of distillation was discussed and optimum conditions were determined. Kat0 and Murano (24G) determined arsenic in water from 0.5 to 50 pg by X-ray fluorescence. Arsine is collected on a silver nitrate-impregnated filter paper by the Gutzeit method and arsenic determined by comparing the intensity of the arsenic K a line with that of a standard sample. The relative standard deviation is 4% for 10 pg As. A method is described by Goulden and Brooksbank (19G) for the determination of submicrogram levels of antimony, arsenic, and selenium in natural waters. Stibine, arsine, and hydrogen selenide are produced from the samples in an automated system and passed to a tube furnace of an atomic absorption spectrophotometer. The method will analyze 40 samples per hour with a limit of detection of 0.1 pgll. for arsenic and selenium and 0.5 pgll. for antimony. An automated method for determining arsenic and antimony as their hydrides by atomic absorption spectrophotometry using sodium borohydride and feeding the hydrides into an argon-hydrogen entrained air flame was reported by Kan (23G). The sensitivity is 6 ppb for arsenic and 8 ppb for antimony. Braman, Justen, and Foreback ( 7 G ) described a direct volatilization-spectral emission system for determining arsenic and antimony in natural waters. Arsine and stibine are formed and then swept out of solution with helium. The hydrides are passed through a calcium sulfate drying tube and through a dc discharge detector. Limits of detection are near 0.5 and 1 ng for antimony and arsenic, respectively. A method based on anodic stripping voltammetry at the mercury-coated graphite electrode was developed by Gilbert and Hume (18G) for the direct determination of bismuth and antimony in sea water. The bismuth method is discussed in the previous section. Antimony is plated from sea water made 4M with hydrochloric acid and measured at the same potential as for bismuth which gives a peak proportional to the sum of bismuth and antimony. Ciaccio (11G) reviewed methods of analyzing environmental samples for nitrogen and phosphorous. Tables are given listing the various analytical methods, with sensitivities, limitations, and 63 references. Armstrong (2G) re342R

ported on the reliability of several methods for determining orthophosphate; the preservation of samples, and the need to find a reliable method determining organic phosphates. Nelson and Romkens (35G) discussed the suitability of freezing as a method of preserving runoff samples for analysis of dissolved phosphate. They stated that frozen storage is not a good method unless sediment is removed prior to freezing. Shapiro (44G) reported that dissolved orthophosphate in natural waters can be determined accurately by field extraction of phosphomolybdic acid into isobutyl alcohol followed by laboratory analysis as much as 2 weeks later. Lyutsarev, Sapozhnikov, and Selifonova (30G) used an ultraviolet irradiator to decompose organic phosphorous compounds prior to the determination of the orthophosphate, which is formed during the irradiation, by the method of Murphy and Reily. Methods are described by Pakalns and McAllister (37G) for the determination of inorganic phosphate and total phosphorus in sea water by extracting the molybdophosphoric acid with isobutyl acetate and then reducing the solution to heteropoly blue. Arsenic and silicate in amounts encountered in sea water do not interfere. Cescon and Scarazzato (10G) also proposed the use of isobutyl acetate for the determination of low levels of phosphate in sea water. Huber (21G) and Crawford, Lin, and Huber (14G) proposed the use of atomic absorption spectrophotometric inhibition titration for the determination of orthophosphate and polyphosphates in surface and waste waters. Details of the procedure are given. The results compare well with those obtained by other methods. Lin and Huber (28G) also determined silicate, phosphate, and sulfate with a single titration using the above-mentioned technique. Seitz (43G) evaluated a flame spectrophotometric method for determining phosphorus in water. Response is linear from 3 pgll., the detection limit, to 120 mgb., the highest concentration tested. Cation exchange must be used to eliminate metal ions which depress the phosphorus emission. Volatile phosphorus compounds produce a larger signal for a given concentration than nonvolatile phosphorus compounds. A cathodic stripping chronopotentiometric method for the determination of phosphate in water was developed by Lundquist and Cox (29G), and Cox and Lundquist (13G). The method is based upon stripping of an electrode-deposited copper phosphate consisting of a mixture of copper(I1) salts of the conjugate bases of phosphoric acid. The detection limit is 10 ppb. Huber, Karweik, and Reim (22G) investigated the cathodic response of the lead oxide electrode to polyphosphate species and fabrication and response of various forms of the electrode. The method is specific for polyphosphates in the presence of orthophosphate and should be applicable to water investigations. Totally automated procedures for the concurrent determination of ortho-, and ortho-plus-hydrolyzable or total phosphate in waste- and surface-water samples are described by Osburn, Lemmel, and Downey (36G). The orthophosphate formed in all cases is measured colorimetrically by modifications of the Murphy and Riley reagent. MangelsdoTf (31C ) described a similar AutoAnalyzer system to determine phosphate in sea water especially for shipboard use. A flame emission photometer was developed by Prager (38G) for automatically monitoring total phosphorus in water. The sample is atomized in an ultrasonic analyzer into a hydrogen flame and the emission is measured at 525 nm. The detection limit is approximately 2 ppb. Organic and inorganic phosphorus is distinguished with ion-exchange resins. Pugh and Gibbs (39G) adapted


an automatic analyzer for the determination of phosphate in sea water. Fanning and Pilson (16G)reported that the precision and accuracy of methods for the determination of dissolved silica in natural waters can be greatly improved by taking account of the time courses of some of the reactions involved. Based on results from a metol-sulfite reduction method, the molar absorptivity of a reduced mixture of the LY and p isomers of molybdosilicic acid in sea water is affected only by the ionic strength but not by the nature of the component salts of the solution. The determination of silicates and silicic acid in water by the precipitation of an insoluble alkaloidal molybdosilicate complex of high molecular weight was studied by Defosse (15G).The complex has sufficient mass to permit turbidimetric measurement. Martynova, Fursenko, and Popov (33G)used strong base anion exchange to concentrate silica prior to colorimetric determination. In the analysis of solutions containing 5 and 10 pg per liter of silicic acid, the relative error was less than 5%.

HALIDES Several investigators, Ruzicka and Mrklas (28H),Selig (33H),Shiraishi et al. (35H),and Warner (40H)have either reviewed, compared, or described methods for the manual determination of fluoride using ion-selective fluoride electrodes. An automated system for determining fluoride in the ppb range with an ion-selective electrode was described by Sekerka and Lechner (31H, 32H). Salyamon and Popelkovskaya (29H)evaluated a number of colorimetric methods for determining fluoride. Included are the zirconium-SPADNS, cerium alizarin complexon, and zirconium-eriochrome cyanine methods. A colorimetric method for the determination of fluoride in aqueous solutions with a solid analytical reagent was proposed by Mehra and Lambert (21H). The detection limit, however, is only 1 ppm. Interfering ions are first eliminated by ion exchange. A simple apparatus for distilling fluoride prior to measurement with zirconium-alizarin is described by Kasegawa (17H). Yabe, Takahashi, and Sat0 (41H) concentrated fluoride from water by ion exchange using Dowex-2X prior to its determination by neutron activation. Fluoride a t the 1ppm level was determined precisely (-99%) without any interferences due to coexistent ions in the sample. Methods are reported by Kalaushin ( 1 6 H ) ,Mainka et al. (20H), Ogata (25H), Pilipenko, Ol’khovich, and Gakal (27H),and Selmer-Olsen and Oien (34H) for determining chloride potentiometrically. Descriptions of the electrode systems are given. Comparison of results by other methods are reported in some cases. The methods are used to determine chloride in boiler water, drinking water, and sea water. Sanchez Crespo (30H) used potentiometric titration with silver nitrate to determine chloride and compared results with the Mohr method. An automated potentiometric titration method using silver nitrate to determine chloride in sea water is reported by D’Arrigo, DeRobertis, and Casale ( 3 H ) . Jacobsen and Tandberg ( 1 5 H ) constructed a simple instrument for coulometric titration of chloride in natural water. The determinations of chloride are performed by generation of silver ions and dead-stop determination of the end point. Satisfactory results are obtained in the range of 0.1 to 100 pg per ml of chloride. A microcoulometric method for determining chloride in water is described by Montiel and Dupont (23H).Chloride is precipitated by sil-

ver ion produced by a pulsating current a t the silver anode, each pulse corresponding to a known quantity of silver. The end of the titration is determined potentiometrically. The precision is 0.5 and 0.3% for 15 and 100 mg per liter of chloride, respectively. The effect of other ions was investigated. A new indicator, N-methyldiphenylamine-4-sulfonic acid, for argentometric determination of chloride in borehole waters and other materials was developed by Chernova et al. (2H). The color change a t the equivalence point from blue-lilac to rose is reported to be sharp. Details on the preparation of the indicator are given. Goryunova, Chernova, and Frumina ( 1 1 H ) described a new indicator, tetraethylbis(4-natriumtetrazolylazo-5)acetate, which reacts with mercuric(I1) ion to form a red ‘complex suitable for visual mercurimetric determination of chloride and bromide. There is a sharp change from yellow to red. The method was used to determine 3 to 150 mg of chloride in boiler water. A semi-automated Mohr method for determining chloride in sea water is described by Grasshoff and Wenck (12H). The titrant is added from a motor-driven piston buret. A new method for the determination of chloride, which was applied to samples of drinking water, based on the formation of phenyl mercuric chloride, its extraction into chloroform and reaction with sodium diethyldithiocarbamate to form phenylmercurydiethyldithiocarbamate was developed by Belcher, Rodriguez-Vazquez, and Stephen (IH).The complex is measured by ultraviolet spectrophotometry at either 257 or 297 nm. Amounts of chloride in the range 0.04 to 0.32 ppm can be determined in 250-ml aliquot samples. Gambrel1 ( 6 H ) used atomic absorption spectrophotometry for end-point determination of chloride in water. Two different increments of standard silver nitrate solution are added to two identical aliquots of sample and a small portion of each aliquot is then filtered. Silver is then determined in both portions and chloride calculated from equations given in the paper. The author stated that it should be possible to detect at least 0.5 ppm chloride. A radiometric method is reported by Vilenskii and Koroleva (39H) for the determination of chloride in natural water with a 0.0036 pg/ml sensitivity. A photometric determination of bromide in natural water in the concentration range of 0.02 to 8.0 mg/l. based on the oxidation of bromide by sodium hypochlorite and the decolorization of methyl orange by released bromine was developed by Morgen, Vlasov, and Mazko (24H). Iodide at concentrations three times greater than bromide, chloride up to 300 mg/l., and fluoride, carbonate, and bicarbonate do not interfere. A direct X-ray spectrophotometric method for the determination of bromine in water was investigated by Deutsch ( 5 H ) . Once calibrated, the procedure requires no standards. The method is based on the normalization of the background intensity of the sample to the background intensity of a pure water sample. The factor thus obtained is used to normalize the sample peak intensity which is then compared to previously prepared permanent standards. Szucs (38H) determined the iodide and bromide content of mineral waters by potentiometric titration. Iodide is determined directly with a iodide-selective membrane electrode. Bromide is first separated from other halides by using chloroamine T and then measured with a silver indicator electrode using a saturated calomel electrode for reference. Accuracy approaches that of classical methods. Hetman ( I 4 H ) described an ac polarographic method to determine iodide and bromide in water simultaneously. Io-


* 343R

dide and bromide are first oxidized to iodate and bromate with sodium hypochlorite. Kelus ( 1 9 H ) studied several colorimetric methods for determining iodine in water and reported that the leuco violet method was most efficient and suitable for the determination of active iodine in the presence of chlorine. Ghimicescu, Stan, and Dragomir (10H) developed a spectrophotometric method for determining iodide in water based on the oxidation of iodide with hydrogen peroxide to iodine, which then gives a blue color with o-tolidine. The sensitivity is 0.02 pg/ml. Ganchev and Atanasova ( 8 H ) determined iodide as nitron triiodide spectrophotometrically. The compound is extracted into dichloroethane and the absorbance measured at 295 nm. The method was used to determine traces of iodide in natural water, air, and other materials after conversion to iodide. Keller et al. (18H) made kinetic measurements in an AutoAnalyzer system in order to define optimal conditions for the determination of iodine at the pgh. level in water by means of the Sandell-Kolthoff reaction. Garcia Jeronimo ( 9 H ) used the sodium arsenate-ceric sulfate reaction to catalytically determine iodine in water at levels of 0.27 to 400 pg/l. Shveikina ( 3 6 H ) compared two kinetic methods for determining iodine by the iodide-catalyzed oxidation of thiocyanate by nitrite in nitric acid media. The method, based on colorimetric determination of the residual thiocyanate concentration, had a lower error then the method based on nephelometric determination of sulfate formed as a product of the reaction. A titrimetric method for the determination of iodine in well water after its oxidation to [IC12]- was developed by Ganchev and Atanasova ( 7 H ) .The method is based on the oxidizing action of [IC12]- on iodide and on titration of the liberated iodine with thiosulfate. Optimum conditions for the amperometric determination of pg/l. levels of iodide in oil well waters in the presence of bromide and chloride by using K3[Fe(CN)6] as the titrant with a platinum indicating electrode are described by Songina et al. (37H). An amperometric method for the determination of iodide in mineral waters by potassium dichromate is reported by Milyaeva (22H). Greve and Haring ( 1 3 H ) determined organically bound halogens in surface and other waters by macrocoulometry. As little as 0.5 pg per liter of chloride can be determined. Desai, Desai, and Gandhi (4H)reported that gentisaldehyde and its oxime derivative were suitable indicators for the determination of total halides in water using silver nitrate as the titrant. The pH is kept between 5.5 and 6.5. Colorimetric methods for the determination of free available and bound, active chlorine, chlorine dioxide, chlorites, bromine, iodine, and ozone in water using tablets of diethyl-p-phenylenediamine are described by Palin ( 2 6 H ) .

SULFATE AND SULFIDE Holz and Kremers (65) described an automated photometric method for the determination of sulfate in drinking and surface waters. Thorium ion forms a violet-colored complex with SPADNS reagent. Sulfate in the presence of the thorium-SPADNS chelate forms a colorless thorium complex. The decrease of the violet-colored chelate is used to determine the sulfate content. A spectrophotometric ,method which uses 2-aminoperimidine hydrochloride as a precipitating reagent is recommended by Jones and Stephen ( 8 4 for the determination of sulfate in rain and surface waters between 4 and 120 ppm. The excess reagent is measured at 305 nm. The relative standard deviation for 50 344R


NO. 5,

ppm of sulfate is 3.7%. Burns et al. (45)described a similar procedure for the determination of sulfate in rain water. Jasinski and Trachtenberg (75) presented some preliminary data on the application of iron-doped chalcogenide glass electrodes for the determination of sulfate in water. The interference of other ions is evaluated. Mascini (95) described a titrimetric method for determining sulfate in the range 20 to 3000 ppm in mineral waters and sea waters using a lead ion-selective electrode. Chloride and bicarbonate are separated from the sample by passing twice through a cation-exchange resin, first in the silver form and then in the acid form. The sulfate in the eluant is then titrated with lead nitrate. Barcia Goyanes and De Miguel Ponte (15)determined sulfate in water by an indirect titrimetric procedure. Cations are eliminated by ion exchange and sulfate is then precipitated with barium chloride. The excess barium is titrated with EDTA solution using Eriochrome as indicator. A direct titrimetric procedure for determining sulfate in water is described by Rasnick and Nakayama (11J).The sample is titrated with barium chloride using nitrochromeazo as indicator. Details of the procedure are included in the abstract. Results obtained by this method are similar to those obtained by gravimetric determination. Nasu (IOJ)determined microamounts of sulfate in snow and river waters fluorometrically. The method is based on the decrease of fluorescence of the thorium-morin complex in the presence of sulfate. Vlasov, Morgen, and Tyutin (145)also used the thorium-morin method to determine sulfate in weakly mineralized rain water. Within the range of 0 to 800 pg per liter, the fluorescence is a linear function of sulfate concentration. An indirect polarographic determination of sulfate in tap water in the presence of phosphate was reported by Gregorowicz, Kowalski, and Gorka (5J).Phosphate and sulfate are precipitated with lead nitrate. The precipitate is leached with 1M nitric acid to remove the phosphate, the lead sulfate remaining is dissolved in 30% sodium potassium tartrate, and lead is determined polarographically using the dissolution reagent as the suppogting electrolyte. Roebke (125) removed free hydrogen sulfide and hydrochloric acid-soluble sulfides in water by passing nitrogen through an acidified sample in an oven a t 50 to 60°. The liberated hydrogen sulfide is determined colorimetrically by the molybdenum blue method. The apparatus is described. Bethea and Bethea ( 3 5 ) described an automated colorimetric method which uses sodium nitroprusside as the color-forming reagent to determine sulfide in water. Beer’s law is followed up to 40 pug per ml of sulfide. Barica ( 2 4 reported that sodium sulfide solutions used in the determination of sulfide in water can be standardized using a silver-sulfide electrode to detect the end point. Standard silver nitrate is the titrant. The concentrations agreed to within 3% of the values obtained by the conventional iodometric standardization. Weiss (15J)applied a sulfide electrode to the direct potentiometric determination, as well as to the potentiometric titration of sulfides in water. With these procedures, it is possible to determine 0.003 to 300 mg per liter of sulfide. Taylor and Zeitlin ( 1 3 5 ) investigated the relationship between matrix absorption and enhancement effects as observed in the determination of sulfur in sea water by X-ray fluorescence. The scattered radiation method with soft scattered bremsstrahlung affords only slight compensation for matrix effects, although it does effectively diminish effects of instrumental variations and sample inhomogeneities.

APRIL 1975

NITRATE, NITRITE, AMMONIA, ORGANIC NITROGEN, AND CYANIDE A review with 409 references on the colorimetric determination of nitrate in natural products with special reference to fresh and saline waters was prepared by Dabrowska (14K).Ciaccio (12K) reviewed methods of analyzing environmental samples for nitrogen. Tables are given listing the various analytical methods available, with sensitivities, limitations, and 63 references. The validity of the brucine method for the determination of nitrate was examined by Holty and Potworowski (24K) when it was found that samples yielded higher concentrations of nitrate upon dilution. The shape of the absorbance curve a t 410 nm is totally dependent on brucine-to-nitrate stoichiometry, thus necessitating an approximation of nitrate concentration in the water prior to analysis to avoid gross errors in calculations. Nawratil, Marcantonatos, and Monnier (33K)described a colorimetric method for the determination of nitrate in water. The method is based on the reaction of nitric acid and bianthronyl in 96% sulfuric acid. Iron interferes; chloride a t 70 mg per liter also gives low results. A UV spectrophotometric method for determining nitrate in drinking water is described by Monselise (31K) and compared to the ASTM brucine method. The only salt to interfere is sodium carbonate. The absorbance is measured a t 220 nm. Pound (37K)reported that an atomic absorption spectrophotometer can be converted to a UV spectrophotometer for the determination of nitrate in water by adding a source of UV radiation and a mount for cells. Mertens and Massart (27K) determined nitrate in mineral water in the 0.5- to 5-ppm concentration range by UV spectrophotometry and also with a nitrate-selective electrode. Interfering ions are discussed. The electrode method is best adapted for water with low mineral content. Hulanicki, Lewandowski, and Maj (26K) proposed a new design of the liquid-state electrode for nitrate. It contains a porous wick soaked with the liquid ion-exchanger, and has no internal reference solution. Chloride and bicarbonate interference is eliminated by the addition of silver sulfate and a phosphate buffer, which also maintains constant ionic strength. The electrode was used to determine nitrate between 8 and 10 ppm in tap water. Weil and Quentin (46K) also described an ion-electrode method for determining nitrate. Ceausescu and Sirbu (10K) determined nitrate in water in the range of 0 to 31 mg per liter by treating the solution with sodium chloride, concentrated sulfuric acid, and tartrazine, and then titrating with an indigo carmine solution to match a particular colored standard. A new titrimetric method for the determination of nitrate is described by Bodine and Janzen ( 7 K ) .The method is based on the formation of the azo dye resulting from coupling of diazotized sulfanilamide and N - (1-naphthyl)ethylenediamine,and the oxidation of the red color to a clear yellow by titration with sodium hypochlorite. The entire determination requires less than 2 minutes. Stainton (43K) described a simple reduction column for use in the automated determination of nitrate in water. The column is constructed from a 1-meter length of y32inch i.d. Teflon tubing threaded with a 1-meter length of I-mm diameter cadmium wire. Complete details of the system are described. Holz and Kremers (25K)determined nitrate in water automatically using an indirect rhenium method. A modified technique for the automatic determination of nitrate and nitrite in fresh water and sea water is described by Carnada, Troncone, and Saggiomo (9K). The method is based on reduction of nitrate to nitrite using a cadmium column, but differs from Grasshoff's method in

use of reagents to allow diazotization of amines and a change in column manifold to allow addition of reagents. Celardin, Marcantonatos, and Monnier (11K) developed three spectrophotometric methods for the determination of nitrite in water based on diazotization of 4-aminoacetophenone followed by coupling with N - phenyl-1-naphthylamine or N-phenyl-2-naphthylamine.Sam (40K) described a spectrophotometric method for determining as little as 1.4 ppb of nitrite-N in water. The method involves the conversion of nitrite to a red azo dye by diazotization with sulfanilic acid and coupling with N - (1-naphthy1)ethylenediamine dihydrochloride. The absorbance of the dye is measured after it is concentrated on Dowex l-XS anion-exchange resin and eluted with 60% acetic acid. A micromethod for determining nitrite in potable and mineral waters .based on the reaction of nitrite with o-tolidine is reported by Ghimicescu and Dorneanu (18K).A yellow-orange product is formed and is measured spectrophotometrically. The sensitivity is 0.05 pg per ml of nitrite. Bhuchar and Amar ( 6 K ) determined nitrite in polluted water spectrophotometrically with a-thiolacetic acid. A red complex is formed which is stable for 18 hours if extracted into amyl alcohol. Beer's law is obeyed from 0.2 to 40 pg per ml of nitrite. A method for the chemical stabilization of waste-water samples for nitrite determination using mercuric chloride, chloroform, or a sodium hydroxide-sodium carbonate mixture is described by Sprenger (42K). Dah1 (15K) stated that methods for determining ammonia in water should be based on the indophenol blue reaction. Also, the samples should be analyzed no later than 3 days after sampling. No preservatives should be added, but storage a t 4 "C is recommended. Nimura (34K),when determining ammonia by the indophenol method, added a large amount of potassium carbonate to make the indophenol blue formation nearly constant without regard to the salinity of the sample. Zadorojny, Saxton, and Finger (47K) also used a modified indophenol blue method for ammonia. An indirect spectrophotometric method applicable for the determination of ammonia in the range 0.01 to 0.4 ppm is described by Hirakoba et al. (23K). A blue complex produced by reaction with potassium iodide-starch reagent and chloramine compound which is formed by the reaction of ammonia and hypochlorite is measured at 570 nm. Cioce et al. (13K) determined ammonia and amino-acid nitrogen in marine, brackish, and fresh water by a modified automated method. Alkaline hypochlorite and potassium bromide were employed as oxidizing agent and catalyst, respectively. Slawyk and MacIsaac (41K) compared automated indophenol and rubazoic methods for determining ammonia in sea water. The results from the two methods were in good agreement; a correlation coefficient of 0.96 was calculated from the data. Grasshoff and Johannson (22K) also described an automated indophenol blue method for determining ammonia in sea water. The relative standard deviation is 5% between 0.05 and 0.10 pg per liter of ammonia (as N). Benesch and Mangelsdorf ( 5 K ) determined ammonia in sea water by an automated nitroprusside-cyanurate method. The color of the blue quinoid dye is measured a t 600 nm. There is interference from lysine and alanine, but not from six other amino acids tested. In the range 5 to 230 wg per liter of ammonia (as N), the reproducibility is approximately 3%. The ammonia-selective electrode has been used extensively in the past two years: Barica ( 2 K ) ,Beckett and Wilson ( 4 K ) ,Gilbert and Clay (19K),Mertens, Van den Winkel, and Massart (28K),Midgley and Torrance (29K, 30K), Thomas and Booth (44K),and Vandevenne and Oudewater (45K).Results compare favorably with the indophenol blue


345R

and other colorimetric procedures. The electrode method is applicable to routine determination of ammonia down to a t least 0.1 mg per liter. The electrode can also be used for continuous monitoring. A coulometric apparatus is described by Orlova (36K) for the determination of ammonia in sea water. The sea water is evaporated, the liberated ammonia is then passed into the stream of a carrier gas, and titrated with generated hydrogen ions. Ermakova, Stepanov, and Ponomareva (17 K ) designed a diffusion cell to determine ammonia in sea water. The sample is left for 24 hours to diffuse into 0.01N sulfuric acid and then titrated with ‘0.01N sodium hydroxide using violet-red indicator. Samples containing from 0.1 to 2.0 mg per liter of ammonia were analyzed. The effects of freezing, rate of freezing, filtration, preservatives, and the type of storage container on ammonia concentrations of stored sea water samples were investigated by Degobbis (16K).Without any treatment, ammonia concentrations increased in glass containers and decreased in polyethylene containers. Freezing stabilized ammonia concentrations. Preservation with phenol a t the same concentration used in the method stabilized unfrozen samples for up to 2 weeks. Construction details are given by Pugh and Chubb (38K) for a 3-channel automatic analyzer for ammonia, nitrate, and nitrite determinations in sea water. Banoub ( I K ) described a procedure for the determination of particulate organic nitrogen in natural waters by using Kjeldahl digestion and measurement of ammonia by an indophenol blue method. A dry-combustion method for the simultaneous determination of total organic nitrogen and carbon in sea water is reported by Gordon and Sutcliffe (20K). The removal of interference of thiocyanate in the cyanide determination in the ordinary distillation method was studied by Nagano, Yoshimura, and Onishi (32K). Total cyanide concentration in several agricultural water samples was determined by oxidation in an acidic solution with the use of Y, equivalent of potassium permanganate to the amount of thiocyanate during the distillation. Bowling, Sheehan, and Delfino ( 8 K ) reported that a modification of the Serfass distillation with an absorption tube resulted in an interference-free solution suitable for the pyridine-pyrazolone colorimetric determination of cyanide in surface waters. Goulden, Afghan, and Brooksbank (21K) described two methods for determining simple and complex cyanides in water. In the first, modifications to the manual distillation procedure given in “Standard Methods” are made to lower the detection limit to 5 gg per liter. Second, an automated pyridine-pyrazolone method is described which has a detection limit of 1 gg per liter of cyanide. Distinction is made between simple and complex cyanides by irradiation with ultraviolet light. The irradiation breaks down complex cyanides, including those of cobalt and iron. An automated benzidine-pyridine method for total cyanide in water and waste water is reported by Royer, Twichell, and Muir (39K). Cyanides are converted to CNBr by reaction with bromine water, and then reacted with benzidine in a pyridine medium to form an intense red color which is proportional to the cyanide concentration. Complex cyanides are decomposed by a modified Serfass distillation. Bark and Lim (3K) described an indirect polarographic method for determining cyanide in natural water and sewage. The cyanide is distilled from the sample, collected in sodium hydroxide solution, and the cyanide reacted with a known excess amount of copper(I1). The excess copper(I1) is determined polarographically. The detection limit is 0.0025 ppm. 346R


NO. 5,

A method for the determination of cyanide or thiocyanate in water by gas chromatography was suggested by Nota and Palombari ( 3 5 K ) . The method is based on the prior transformation of the cyanide and thiocyanate into CNBr by treating the sample with bromine. The CNBr is then determined by gas-solid chromatography using an electron capture detector. The detection limit is 0.01 ppm.

pH, ALKALINITY, CARBON DIOXIDE, SPECIFIC CONDUCTANCE; AND TURBIDITY Oradovskii ( 4 L ) described a photocolor.imetric method for determining the pH of sea water. The absolute error of this method was reported to be < f 0.01-0.02 pH unit. An accuracy of 0.02 pH unit was achieved by Ben-Yaakov and Ruth (2L) when using an improved in situ pH sensor and signal conditioner. A new method for determining the total carbonate ion concentration in saline waters is discussed by Simpson and Broecker (7L).The Pco2 in equilibrium with an initial solution is determined. Two more Pco2 measurements are made after adding a known amount of strong base and after further adding boric acid. These three Pco2 measurements plus the total inorganic carbon concentration are used to compute the total carbonate concentration of the original solution without the use of any system of apparent dissociation constants. Askne and Brosset (115) described a method for determining strong acid in precipitation, lake water, and airborne matter. Rain water is freed of carbon dioxide and cations by ion exchange before it is titrated with sodium hydroxide. The strong acid is then determined by plotting the Gram function against the volume of base used in titration. Comparative methods for determining carbon dioxide in water were reviewed by Rogers ( 6 ~ 5 )A. semiautomated system for the continuous measurement of the partial pressure of carbon dioxide is discussed by Gordon and Park (3L).It consists of an infrared gas analyzer which measures the carbon dioxide concentration of an air stream which is continuously equilibrated with a sea water sample stream. Sugino, Kitamura, and Obata ( 8 L ) described a pretreatment apparatus for determination of total carbon dioxide in sea water and in decarbonated sea water. The stripped gas from this device is carried by helium into a gas chromatograph which determines the carbon dioxide present. The detection limit is 0.5 ppm. Ovodov and Chudnovskii ( 5 L )studied an electrophoretic method for measuring low-turbidity waters and found it to be very precise for turbidities 160 mg/l. The accuracy is 0.2, 0.5, and 1 mg/l. for suspension concentrations of 2.5, 2.5-10, and 10-60 mg/l., respectively. OXYGEN AND OTHER GASES A sea-going gas chromatographic system for determining dissolved nitrogen, oxygen, argon, and total inorganic carbon in sea water is described by Weiss and Craig (27M). Factors affecting the design, calibration, and shipboard operation of the system are discussed in detail. Results from this procedure were in good agreement with those obtained by other techniques. A new gas chromatographic method for determining carbon dioxide, oxygen, nitrogen, and methane was studied by Tokuev (24M).This simple method has two systems of sample introduction and requires 10-12 min per analysis. Heggie and Reeburgh ( 7 M ) evaluated a gas density balance detector for determining dissolved argon, nitrogen, methane, carbon dioxide, and hydrogen sulfide in water samples. The detector exhibited a motion sensitivity that in many cases prevented determination of gases to be made aboard a ship.

APRIL 1975

The capabilities of available procedures for oxygen determination in water are reviewed by Masson (15M).Volumetric, absorptometric, amperometric, coulometric, conductometric, radiometric, and chromatographic procedures are included in the 127 references. Legler ( 1 4 M ) also investigated various methods of determining oxygen in surface waters. The choice of several methods was dependent upon the scope and circumstances of the involved measurements. Thirteen references are included in a review by Noesel ( 1 7 M ) which gives special emphasis to the membrane polarographic method of determining dissolved oxygen in aqueous media. The influence of extraneous gases, the performance of a number of commercial instruments, and a description of the potentiostatic method for oxygen determination are discussed. Meyer, Posey, and Lantz ( 1 6 M ) investigated an electrochemical method for monitoring the oxygen content of aqueous streams at the ppb level. An exchanger is used in which the dissolved oxygen in the test stream penetrates an oxygen-permeable membrane and equilibrates with the dissolved oxygen in an internal sensor stream. An accuracy of 1-2 ppb has been attained in the 0 to 100 ppb range. A portable polarographic apparatus which includes an oxygen-permeable membrane was used by Kuz'min and Kulikov ( I 3 M )to determine dissolved oxygen in liquids. Steger (23M) also employed a membrane electrode to measure oxygen a t the bottom of flowing waters. A compensation circuit for a dissolved oxygen electrode which will give the best measurement over a temperature range of 5 to 35 "C without the need for recalibration was studied by Raible and Testerman ( 2 I M ) . The best temperature compensation was obtained for a circuit based on a design in which two thermistors were incorporated. An electrochemical apparatus is described by Klimenko and Tsapiv ( I I M ) for the determination of dissolved oxygen in boiler water. This instrument is based on the compensation of the electrical potential difference between two pairs of indifferent measuring electrodes a t different distances. A convenient method of compensating for the effects of salinity on the data acquired from dissolved oxygen meters is presented by Pijanowski ( 2 0 M ) .The correction technique is based on earlier work by Gilbert et al. and is presented in a form suitable for development by computer for specific instruments. 11lustrations demonstrating the methodology include curves for a meter intended basically for use in fresh water as well as for another which employs a fixed value of salinity compensation. Jones and Mullen (8M) examined the reactions of the Winkler determination with a rotating platinum electrode and a recording polarograph. Only about 5 percent of the oxygen reacts a t pH 7; however, the reaction is quantitative at a pH of 9 or greater. The reaction of dissolved oxygen with manganese(I1) is quite rapid. The Miller and Winkler methods for dissolved oxygen were compared by Ellis and Kanamori ( 4 M ) . A precision of f0.05 mg/l. of oxygen was obtained for the Miller method; however, carefully standardized conditions must be used to obtain accurate and reproducible results. Altmann ( I M ) modified the Winkler method by employing Leukoberbelin Blue I. Concentrations between 5 bg and 15 mg/l. of oxygen are determined photometrically by measuring the absorbance of the dye a t 618 nm. Interfering effects of organic substances in water are suppressed by this method. Kamantseva, Popova, and Yakimets ( 1 0 M )reported that the iodometric determination is preferable to the colorimetric method when the Cu2+ and Fe3+ complexes of EDTA are present because the colorimetric indicators are oxidized by these complexes. A series of apparatus were de-

veloped by Kabanova and Budennyi (9M) for the determination of oxygen in water based on the oxidation of T1 to T1+ and determination of the increase of conductance. A sensitivity of 1 pg/l. was obtained for a range of 0 to 100 bgll. of oxygen with a probable error of f5%. Expendable ampoules containing Winkler reagents were used by Ostrom ( 1 8 M )to determine dissolved oxygen in sea water. Bauer, Phillips, and Rupe ( 3 M ) determined free chlorine in water by impregnating a buffered mixture of syringaldazine and vanillinazine into a sheathed paper strip and estimating the concentration by comparing the color obtained with a color chart from prepared standards. The range is 0.2 to 2 ppm chlorine. Bound chlorine, such as chloroamines, do not interfere. A polarographic meter for the continuous determination of residual chlorine in drinking water is discussed by Petrovskaya and Shvetsov (19M). The measurement ranges are 0 to 1.5 and 0 to 3.0 mg/liter chlorine. Guter and Cooper ( 5 M ) and Guter, Cooper, and Sorber ( 6 M ) evaluated five field test kits for determining free chlorine residuals in aqueous solutions. After testing on both synthetic and natural waters, it was concluded that the syringaldazine liquid procedure had absolute specificity for free available chlorine while the N,N-diethyl-pphenylenediamine procedure was the most accurate and precise. A sensitive spectrophotometric method for determining ozone in small quantities of water is presented by Shechter (22M). The oxidation of a buffered iodine solution and spectrophotometric measurement of the triiodide ion liberated by ozone is involved in this method. Different procedures are used for the two ranges of 0.01 to 0.30 ppm and 0.30 to 2.0 ppm, and the reproducibility of results is very high. This method is compared with the standard volumetric method and the differences are presented and discussed. Vasil'ev, Chelysheva, and Veselovskaya (25M) described a method for determining ozone in water containing chlorine. Potassium bromide and sulfosalicyclic acid, in an amount determined by the amount of chlorine present in the water, are added to the water. Potassium iodide, sulfuric acid, and soluble starch are then added and the solution is titrated with hyposulfite. The limitations of the iodine-thiosulfate method for determining ozone in the presence of chlorine is discussed by Ward and Larder (26M). They concluded that the Acid Chrome Violet K method is suitable for measuring 0.1 to 1.0 mg/l. of ozone in the presence of chlorine. The measurement of hydrogen in condensed steam is outlined by Koehle and Fuhrmann (12M). The phase exchanger of the measuring device catalyzes the diffusion of the gas to be absorbed out of the liquid and into the wash gas at the gas-liquid interphase and also catalyzes the transition of the gas particles from the liquid interphase into the wash gas. A thermal conductance chamber is used to continuously evaluate and measure the gas mixture in the gaseous phase. A charged particle activation analysis method is described by Bankert, Bloom and Dietrich ( 2 M ) to rapidly determine low concentrations of nitrogen in water. This I4O method is based on the nuclear reaction 14N P n, which is followed by decay of the I 4 O with emission of a 2.31-MeV a-radiation. Concentrations levels of 1 X 10-8 g/kg can be determined.

+

-

+

DETERGENTS A combined method consisting of ion-exchange separation, extractive separation, and polarographic determination was developed by Linhart ( 4 N ) for determining all types of surfactants in aqueous media. The degradability

ANALYTICAL CHEMISTRY, VOL. 47, NO. 5, A P R I L 1975

347R

and concentration of various surfactants in water were determined. Linearity was observed a t concentrations of 0100 mg per liter. Wickbold (ION)compiled a review with 22 references on the analytical determination of small amounts of nonionic surfactants. Nonionic surfactants were determined by Wickbold ( I I N , I2N) in river and waste waters. The surfactants were extracted with a nitrogen stream into ethyl acetate, precipitated with Dragensdorff's reagent, and the resulting complex was titrated potentiometrically with sodium pyrrolidine-dithiocarboxylate. Concentrations of 0.011-0.026 ppm were determined with a deviation of 115%. Taylor and Waters ( 8 N ) radiometrically determined trace amounts of anionic surfactants in ground water and potable water. The sample is treated with an excess of ferroin solution labeled with 59Fe, extracted with chloroform, and the activity of a portion of the extract is measured. The anionic surfactant content of the sample is determined by the standard addition of sodium lauryl sulfate. Concentrations as low as 0.005 ppm can be determined with a precision of

Water analysis - Analytical Chemistry (ACS Publications)

Recommend Documents