--iueii
Here are sa of the latest advances in sampling, detection, and determination techniques presented at an ACS symposium
L. H. Keith Radian Corporation Austin. Tex. 78766 One of the highlights of the environmental chemistry portion of the Second Chemical Congress of the North American Continent was a symposium on Advances in the Identification and Analysis of Organic Pollutants in Water. The congress was held last August in Las Vegas, Nev. The symposium was a sequel to one conducted in 1975 at the First Chemical Congress. Like its predecessor, this symposium's aim was to present recent advances in methods of sampling, analysis, identification, and quantitation of organic pollutants, as well as protocols. Plenary talks Plenary talks covered three principal topics. First, new data on chlorinated constituents of humic materials in water were presented by Professor Russell Christman of the University of North Carolina as part of the talks on aquatic organic problems. He also included a brief review of the history of organic contaminant detection in water. Other talks addressed global water quality monitoring and programs of the United Nations-sponsored Global Environmental Monitoring System that involve water. Those programs were described by R. Silvio Barabbas of the World Health Organization Collaborating Center on Surface and Ground Water Quality.
Data evaluations W.M. Shackelford and D. M. Cline of EPA's Environmental Research Laboratory (Athens, Ga.) and F. 0. Burchfield et al. from Computer Sciences Corporation have developed an automated software program to identify compounds in 4000 industrial wastewater samples that were previIS6
Environmental Science S. Technology
ously analyzed for EPA priority pollutants. Unidentified compounds are matched against each other to generate groups of spectra that are thought to be reoccurrences of the same compound. A. D. Sauter et al. of Computer Sciences Corporation, and Shackelford and Cline developed a software program that automatically calculates a background-free extracted ion current profile (EICP) for as many as 30 ions concurrently. A piecewise least-square fit through minima in the EICP results in a background-subtracted EICP that has the appearance of the original data, except that most peaks then have essentially baseline resolution. B. Carson et al. of Midwest Research Institute (MRI) described the progress made in compiling a comprehensive list of water pollutants for EPA. The Distribution Register of Organic Pollutants in Water-WaterDROP-conceived by L. H. Keith in 1976, is available as a component of the NIH/EPA Chemical Information System. MRI collects seven types of data for compilation and computerization by Fein-Marquart Associates: citation information, chemical information, water type and treatment, sampling data, concentration, identification technique, and confidence rating.
Man-made water pollutants A man-made reaction is one in which two or more chemicals, at least one of which was introduced by man, react in water under ambient environmental conditions to form a third substance which is considered a pollutant. The most common example is the formation of haloforms in drinking water from the reaction of chlorine with naturally occurring humic substances. Another reaction was discovered by T. I. Bieber and M. L. Trehy from Florida Atlantic University and the City of West Palm Beach Water Department, respectively, when, using
pentane extracts, they analyzed West Palm Beach drinking water samples. Dihaloacetonitriles (DHANs) were identified and shown to originate from the reaction of certain amino acids, polypeptides containing the corresponding amino acid residues on the N-terminus, and humic and fulvic substances having amino acid moieties appended to the ring system. DHANs react with water at elevated pHs, with dechlorinating agents, and with certain chromatographic columns (for example, Chromosorb 1010). This reactivity explains why DHANs were not previously detected when analyses for trihalomethanes were conducted by the purge-and-trap technique. However, the HendersonGlaze liquid-liquid extraction technique is effective for concentrating DHANs, although the analysis must he made quickly or the DHANs will hydrolyze. In spite of their reactivity, DHANs may still pose a threat to water supplies, because dichloroacetonitrile, a common member of this class, is mutagenic in the Ames test. Now that there are methods to identify and quantify this new class of man-made pollutants, one can expect researchers to pay more attention to the analysis of these compounds, especially to evaluate their potential hazard, or lack of it, in drinking water. Knowlege of the effects of various treatments on the mechanism of formation is necessary to understand the chemistry involved. PCBs and pesticides Several papers discussed the analysis and distribution of PCBs in the environment. M. D. Mullin and J. C. Filkins of EPA's Large Lakes Research Station (Grosse Ile, Mich.) use both packed and capillary glass columns for the analytical separations. Distribution of PCBs was studied in both surface waters (M. Pastel et al. in New York), and subsurface waters. The latter study involved atmospheric
0013-936X/81/0915-0156$01.00/0 0 1981 American Chemical Socieiy
The Niagara River was studied for the presence of organic pollutants by R. A. Hites et al. of Indiana University. Analysis of both water and sediment samples at various points between Lake Erie and Lake Ontario identified many unusual anthropogenic compounds not usually found as water pollutants. There are 215 chemical dump sites in western New York near those lakes, and where individual compounds are most abunIndustrial wastewaters dant correlates with suspected dump inputs. The high incidence of fish tuA series of papers dealt with the mors in the western end of Lake Onanalysis of effluents from paper mills. tario is a possible result of some of A. Bjqrseth et al. of the Central Instithese compounds. tute for Industrial Research in Norway A report on the concentration and used a combination of chemical and speciation of sugars in river water was microbiological analyses to characpresented by M. Sweet and E. M. terize spent liquors from different Perdue of Portland State University. stages of chlorine bleacheries. IndiThe analytical scheme they devised vidual compounds were identified by differentiates between dissolved moGC/MS, and the mutagenic activity Surface waters Large drinking water and advanced nosaccharides, polysaccharides, and of the extracts and of individual compounds were tested with the Ames waste treatment plant water samples “humic-bound” saccharides. Their (400-4000 gallons) were concentrated study of the Williamson’River in OrSalmonella bacteria. R. H. Voss et al. from the Pulp and by reverse osmosis. S . V. Lucas et al. egon revealed a correlation of the Paper Research Institute of Canada at from Battelle Laboratories in Colum- humic substances with the largest percentage of the sugars, thus conPointe Claire, Quebec, described a new bus, Ohio, described the extraction, firming the role of humic substances as and convenient method for analyzing fractionation, and capillary GC/MS chlorinated phenols in paper mill ef- analysis of these samples, which re- a major reservoir of dissolved sugars in fluents. Samples are acetylated in situ sulted in the identification of hundreds that river. Another class of nonvolatile organic with acetic anhydride and extracted of compounds in the waters of each with hexane. Analysis of the extract, city (Miami, Philadelphia, New Or- compounds, linear alcohol ethoxylate nonionic surfactants, was determined using splitlens capillary GC with an leans, Seattle, and Ottumwa). S . Eisenreich et al. of the University in surface waters and wastewaters by electron-capture detector, eliminates the usual preisolation or fractionation of Minnesota studied the organic V. Wee from the Procter and Gamble Company in Cincinnati, Ohio. The steps. The time to work up a sample for compounds present in the upper Mislinear alcohol ethoxylates were exGC analysis is thus reduced from up to sissippi River by sampling river water tracted with chloroform, concentrated and sediments. Wastewater effluent several hours to about five minutes. . The seasonal fatesof 15 chlorinated and sludge from the major source of and isolated by ion-exchange and silica-gel chromatography; finally, they compounds were studied by Mirja pollution-the Minneapolis-St. Paul were cleaved to alkyl bromides by Salkinoja-Salonen et al. from the Metro Waste Treatment Plant-were treatment with hydrobromic acid. GC University of Helsinki and the Enso also sampled. Samples were collected Gutzeit Research Center in Finland. on XAD-2 and XAD-8 resin columns, analysis provided a sensitivity in the low parts-per-billion range for these Both waters and sediments were ana- and the concentrated organic extracts compounds. Comparison of influent lyzed for organochlorine compounds. were fractionated by gel permeation and effluent wastewater samples from The study showed that chlorophenolics chromatography. The upper river was do not degrade significantly in winter essentially free of anthropogenic or- a sewage treatment plant indicated that these compounds were effectively and that the rate of mineralization of ganic compounds, but a drastic change removed by biological treatment. organochlorine compounds in sedi- was noted in the river’s organic comR. G. Riley et al. from the Battelle position after the river passed through ments is very low. Laboratory in Richland, Wash., anaTotal organic chlorine was deter- the Twin Cities. pressure chemical ionization mass spectrometric analysis of over a thousand soil samples by J. R. Roberts et al. in Canada. Another useful technique, shown by E. D. Pellizzari et al. of the Research Triangle Institute (North Carolina), was negative ion chemical ionization high-resolution gas chromatography/mass spectrometry (GC/MS) for the analysis of PCBs.
mined in Swedish pulp mill wastewaters using a recently developed method. K. Lindstrom et al. from the Swedish Forest Products Research Laboratory in Stockholm determined that relatively low-molecular-weight chlorinated organics predominate chlorinated wastewaters, while relatively high-molecular-weight chlorinated organics dominate the alkalineextracted wastewaters. Fractions of some extracts were also characterized in detail by GC/MS. In another paper by I. H. Rogers and H. W. Mahood from Fisheries and Ocean Canada in West Vancouver, British Columbia, oxidized resin acids from Douglas fir were characterized in an effort to relate them tosimilar oxidized resin acids identified in kraft pulp mill effluents.
Volume 15, Number 2, Februaty 1981 157
lyzed both water and suspended matter for halogenated organic pollutants in Puget Sound. Purgeable halocarbons were analyzed by the purge-and-trap technique; the heavier compounds were collected by pumping glass-filtered seawater through stainless steel columns packed with XAD-2 resin. The suspended matter was extracted with benzene-methanol in a Soxhlet apparatus. Analyses were performed by GC/MS using a 30-m glass capillary column in the splitless mode. Although phthalate esters are among the most ubiquitous of anthropogenic compounds, few reports exist on their fateand transport in the aquatic environment. With a data base of measured and estimated values of physical and chemical constants (such as alkaline hydrolysis rate constants, biolysis rate constants, and sediment-water partition coefficients), the fate and transport of five phthalate esters were evaluated by the exposure analysis modeling system. N. L. Wdfe et al. from the Athens. Ga. EPA Environmental Research Laboratory found that no single process is dominant for all esters in all ecosystems. Dimethyl phthalate and di(2-ethylhexyl) phthalate represent the extremes of chemical and physical properties of the series. Dimethyl phthalate undergoes hydrolysis, for example, at almost the same rate in distilled water as in a eutrophic or oligotrophic lake. However, di(2-ethylhexyl) phthalate hydrolysis is a thousand times slower in a eutrophic lake because of partitioning to sediments. A smaller decrease in hydrolysis is observed in an oligotrophic lake because of the less sorptive sediments. Most direct-acting mutagens and carcinogens are also electrophiles and can be detected in environmental
samples by reaction with chromophoric nucleophiles. A. M. Cheh and R. E. Carlson of the Universityof Minnesota have found that 4-nitrothiophenolate anion is an especially good labeling agent for electrophiles. Labeling of unknown electrophiles in water Samples can reveal which components of the mixture should receive priority isolation (by high-pressure liquid chromatography) and identification (by mass spectrometry). Small amounts of unknown electrophiles in a large matrix of nonelectrophilic organics can be easily detected with this labeling. Water treatment J. DeMarco et al. from EPA and Cincinnati's Water Works reported on the assessment of a large-scale granular activated carbon treatment system for removal of organics from drinking water. Volatile organics were monitored with the Bellar-Lichtenberg purge-and-trap technique, and a few samples were subjected to the Crob closed-loop stripping procedure. Early depletion of the adsorptive capacity was observed for total organic carbon, trihalomethane precursors, and certain specific compounds. such as chloroform. R. M. Barkley et al. of the University of Colorado and Boulder's Water Quality Laboratory described a program withthecityof Boulderin which the water is monitored and the water treatment parameters are varied. Chloroform and toluene were the most concentrated volatile compounds in the finished water. Advances in methodology Plenary lectures were presented by Dale Rushneck from Interface, Inc. (for Bill Telliard of EPA's Effluent
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Analysis. Determining rrace organics by p r chromaroxraphy 158
Environmental Science (L Technology
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Guidelines Division) and by Ron Kagel of Dow Chemical USA (representing the Chemical Manufacturers Association). Rushneck and Telliard described EPA's initial efforts to use stable labeled (deuterium and "C) standards as spikes to improve dramatically the accuracy of measuring organic priority pollutants in water. They also told of plans for analyzing the 1976 Consent Decree Appendix C priority pollutants. Representative members of three general classes-terpenes, secondary amines, and alkyl ethers-have tentatively been selected through the use of guidelines similar to those used to choose Appendix A priority pollutants. Kagel suggests the need for a national or even international agreement on what constitutes a valid environmental measurement. The questions of the appropriate criteria for limits of detection, determination, and validation and the role of bias and interlaboratory variability must, he points out, be resolved within the scientific, rather than the legal, community. Industry has consistently advocated validation of EPA's priority pollutant programs and analytical protocols, but the debate over validation continues, and statistically meaningful results remain as elusive as ever.
Protocols EPA has expended a major effort during the past two years to developa Master Analytical Scheme-a total scheme to include analysis of organic compounds of all volatility types and of almost all functional groups in almost any type of water sample. This ambitious project was summarized in five papers. J. E. Gebhart et al. of Gulf South Research Institute (New Orleans, La.) described the development of optimum techniques for isolating the various types of organic pollutants in water, and concentrating them to the. point where GC or GC/MS analysis is possible. J. F. Ryan et al., from the same institute, discussed the factors that influence precision and accuracy of GC/MS data. A. W. Garrison et al. from EPA's Environmental Research Laboratory in Athens, Ga.. summarized the various procedures that comprise the Master Analytical Scheme and reduced them to a logical sequence of decision points within a master flow diagram. L. Michael et al. of Research Triangle Institute and EPA's Athens laboratory followed with a brief description of the analysis of nine water
samples from tap water, surface water, and municipal, industrial, and energy-related wastewaters. These water samples were analyzed “blind” by three laboratories that used the Master Analytical Scheme. I n addition to internal standards spiked at the sample collection site, external standards were also added to the sample extracts to provide a comprehensive quality assurance program. The final paper of the series, by K. Tomer et al. from Research Triangle Institute and the Athens EPA laboratory, summarized the factors that were found to influence the accuracy and precision of quantitation of the organic compounds when GC/MS techniques were used. A more limited protocol has also been developed by P. A. Boland et al. of SRI International (Menlo Park, Calif.) for analyzing a broad range of specific organic compounds in water. This protocol was developed with minimum set-up, labor, and capital equipment requirements, so the technology can be transferred to drinking water utilities. The protocol involves separating the organic pollutants into several fractions, followed by G C analysis. Confirmation by GC/MS produced an overall confirmation rate of 85% for the purgeable halocarbons and 40% for compounds in the base/neutral extractable fraction. Thus, GC/MS confirmation was recommended for all fractions. excevt the Dureeable halocarbons. Hope Miller et al. from Midwest Research Institute has been develoDine procedures for the analysis of aboit 66 pesticides. Each pesticide was tested with standard methodology, then modifications were devised to circumvent problem areas. Good success was achieved, and 80% of the pesticides could be determined at I pg/L or less. Another scheme for the routine analysis of purgeable compounds in drinking water wasdescribed by H. J. Brass et al. from EPA’s Cincinnati Office of Drinking Water. They developed an automated analysis that uses GC/MS EICR that can routinely analyze for trihalomethanes and purgeable synthetic organic chemicals with good accuracy and precision at 0. I -0.5-pglL levels. Traditional analyses of EPA’s priority pollutants require four different packed columns. Detection levels generally range from about 1-100 pg/L. A. R. Trussell et al. from JMM Environmental Research Laboratory (Pasadena, Calif.) described a technique that uses a single-fused silica open tubular capillary column for all
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four priority pollutant fractions. Column flexibility allowed it to be looped for focused cryogenic cooling during the thermal desorption step of purgeable organic analyses. Improved sensitivity allowed parts-per-trillion analyses in some instances. Walter Giger and Christian Schaffner of the Swiss Federal Institute for Water Resources and Water Pollution Control described a procedure that successfully allows the determination of free phenols and carboxylic acids in water. Distillation of the acidified water sample is followed by alkaline extraction at pH 2 to remove nonacidic compounds. This concentrates acids and phenols so they can be chromatographed without derivatization on glass capillary columns which are deactivated by persilylation of the active sites and coated with OC-73. This procedure works well with most chlorinated phenols (4-chlorophenol is an exception), but highly soluble phenols, such as guaiacol, nitrophenols, and phenol itself, give poor recoveries. Robert Freeman of Hewlett-Packard’s Avondale, Pa., laboratory also described chromatographic procedures that allow underivatized analysis of the acidic priority pollutants using capillary columns. A study of the column and solute effects with open tubular columns showed that thedeactivating agent used in the preparation of an open tubular column is the determining factor when polar acidic compounds, at low concentrations, are analyzed. Although the liquid-phase affects compound separations, the degree of reversible or irreversible adsorption on the column is deter-
mined by the deactivatingagent, if the column is made of used silica. Barbara Kingsley et al. from S R I International and EPA’s Office of Drinking Water in Cincinnati, described a comprehensive quality assurance program to quantitatively analyze 500 drinking water systems for total organic carbon, purgeable halocarbons, and aromatic compounds. Duplicate analyses, confirmatory G C and GC/MS analyses, blind and split-sample analyses, and high- and low-level quality control sample analyses were all utilized. Stable labeled standards 6. N. Colby and A. E. Rosecrance of Systems, Science and Software (La Jolla, Calif.) provided data that show the superiority of using stable labeled deuterium and ‘IC compounds as tracers and internal standards over other methods, such as standard additions. Isotope dilution techniques that use nine labeled compounds gave a mean error of f 4 5 % for the same data obtained from standard addition techniques to establish and compensate for compound recoveries. The impact of this work may heavily influence EPA’s future protocol development for the analysis of priority pollutants in industrial wastewaters. L. Ghannam et al. from Oregon State University and EPA’s laboratory in Corvallis, Ore., have proposed dysprosium(l1l)trisacetylacetonate and dysprosium(lll)trisdibenzylmethane as stable label tracers. The n-octanollwater partition coefficients and water solubility of these three compounds have been determined. Certain anthropogenic compounds, Volume 15, Number 2, Februaw 1981 159
such as methyl perimiphos, that have similar partition coefficients and solubilities should behave similarly with respect to adsorption on sediments, bioaccumulation, and the like. The advantage of using these stable labeled compounds as tracers is that the central metal atom is easily detected by neutron activation analyses, so that large numbers of samples can be processed at minimum expense and with minimum sample preparation. Sample concentration Microextraction techniques were the subject of two papers. Microextraction is one-step extraction in which the volume of solvent is small, relative to the volume of the water. J. W. Rhoades and C. P. Nulton of Southwest Research Institute (San Antonio, Tex.) described the application of this technique to several classes of priority pollutants. Results obtained by microextraction in sample spiking experiments and by duplicate analyses of industrial process waters and effluents were compared to results obtained by more exhaustive extraction approaches. K. E. Thrun and J. E. Oberholtzer of A. D. Little, Inc. (Cambridge, Mass.) studied the effects of sampleto-solvent ratios, the presence of other substances, and varying ionic strength on the microextraction of several aromatic compounds from water pentane. The technique was also studied with a wastewater containing high levels of suspended solids. In this case, the shaking time had to be increased from 2 min to 15 min in order to recover the test compounds efficiently. William Glaze et al. of North Texas State University described an optimization of the pentane liquid-liquid extraction method for the analysis of trace organic compounds in water. The sample size was reduced from 120 mL to 20 mL. Shaking with 1 mL of pentane for about a minute extracts the compounds of interest, which are then analyzed on packed or capillary GC columns by electron-capture of flame-ionization detectors. T. L. Yohe and I. L. Suffet of Drexel University have constructed and tested, for 15 weeks, a continuous liquid-liquid extractor that examines finished Philadelphia drinking water. The extractor isolates and enriches trace organic compounds in the water, and operates while unattended. Resin technology Resins continue to be investigated as a means for concentrating organic pollutants from water. G. A. Junk and J. J. Richard of the U.S. DOE labo160
Environmental Science & Technology
ratory in Ames, Iowa, prepared an anion-exchange resin from XAD-4 by chloromethylation and use of trimethylamine to form the ammonium salt, The resin was tested with distilled water spiked with model compounds, and the anionic organic compounds were then eluted with diethyl ether saturated with HCl. The average recovery of the anionic compounds was 90% and similar high recoveries of the neutral compounds were also obtained. J. P. Ryan and J. S. Fritz, also from the Ames Laboratory-US. DOE and Iowa State University, described the thermal desorption of organics from XAD-4 resin. After the organic compounds had been adsorbed onto the resin, the small tubes containing the resin were placed in a specially designed apparatus and were thermally desorbed. The desorbed compounds were trapped on a small Tenax precolumn and were, in turn, thermally desorbed from this to a glass capillary column; high-resolution chromatography then separated the compounds of the mixture. Although this technique was developed for the concentration and analysis of volatile aromatic compounds in water, it also has obvious applications for other volatile classes of pollutants as well. Nitrophenols have always been problem compounds to isolate from water and to analyze. A. F. Haeberer and T. A. Scott of the Athens EPA laboratory isolated nitrophenols by means of a mixed resin system of XAD-4 and XAD-8. Recovery studies of model compounds at 1 ppb and 10 ppb in Athens tap water resulted in yields of 95% or higher. Cesium silicate isolation of acidic components from complex mixtures resulted in the best cleanup recoveries of the nitrophenols. Analysis was performed by HPLC, using reverse-phase liquid chromatography. Polycyclic aromatic hydrocarbons were concentrated from water by J. E. Caton et al. of Oak Ridge National Laboratory with XAD-2 resin, three reverse-phase HPLC resins, and liq- , uid-liquid extraction with methylene chloride. Recoveries were determined by spiking the water samples with 14C-naphthalene or 14C-benzo[a]pyrene prior to the isolation step. The specific compounds were analyzed with capillary GC or reverse-phase liquid chromatography. Recoveries were 80-100%. Anomalously low recoveries of benzo[a]pyrene (BaP) from several types of water samples were observed by Peter Landrum from the Savannah River Ecology Laboratory. He found
that dissolved minerals and humic materials drastically reduce the trapping efficiency of BaP on XAD-4 resin; BaP is apparently adsorbed preferentially by particles and dissolved organics.
HPLC methodology HPLC is beginning to play a large part in the separation of organic water pollutants. This is only logical; greater than 80% of the organic mass in water is too polar, or of too high molecular weight, to be separated by gas chromatography. J. A. Graham and A. W. Garrison of EPA’s Athens Environmental Research Laboratory have used commercial reverse-phase liquid chromatography to analyze for a series of standard compounds over a wide range of concentrations. The samples are concentrated on a precolumn of octadecylsilica and then eluted onto the analytical column. Acids must first be derivatized with tetrabutyl ammonium phosphate, an ion-pairing reagent; only then could they be concentrated on the precolumn. Robert Jolley et al. of Oak Ridge National Laboratories (Tennessee) used HPLC to separate the nonvolatile organic constituents from municipal wastewater. In screening the separated constituents, they found that treatment plants using ozone or chlorine for disinfection formed mutagenic by-products; only ultraviolet radiation did not. At the National Bureau of Standards in Washington, D.C., several approaches to the rapid analysis of organic priority pollutants are being evaluated. H. Hertz et al. described two: HPLC/MS, for polynuclear aromatic hydrocarbons, and fluoroimmunoassay, for dinitrophenols. Haeberer and Scott of the EPA Environmental Research Laboratory investigated two HPLC procedures for analysis of nitrosamines in water. They first accumulated the compounds from water on a 50:50 mixture of XAD-4 and XAD-8 macroreticular resin; after elution, the samples were partitioned in methylene chloride, concentrated, and chromatographed by HPLC on a Spherisorb ODS column with the aid of a photoconductivity detector. The second method added an initial derivatization with 7-chloro-4-nitrobenzo-2-oxa- 1,3-diazole and used HPLC with a fluoresence detector. This latter method was more laborintensive and less successful than the first. Sludge methodology Sewage and sludge samples offer some challenging microanalytical
schematic for trace organlc pollutant analysb 1. Purgeables
40-mL vial chilled at 0 "C Gas chromatograph or GClMS
2. Pestbldes 3. Es~l./neutnlS 4. Phenols
10-mL concentrate
3 Fractions
1- gal lug chilled at 0 "C
methylene chloride
I-mL concentrate of badneutrals
problems because of their high solids content and complexity. C. L. Haile et al. at Midwest Research Institute (Kansas City, Ma.) have used the basic purge-and-trap technique; however, because of foaming problems, they had to first dilute the samples to a suspended solids wntent of 0.5%. Various modifications of the standard technique were tried to see if an increase in recovery of spiked compounds could be obtained. These included stirred purge, dynamic headspace techniques. Each of these, however, produced variable recoveries that were lower than those observed with the conventional nonagitated purge tube. V.Lopez-Avila et al. from Midwest Research Institute investigated methods for the recovery of extractable organics. Quantitative recoveries of most of 16 model compounds from sludge were obtained when the sludges were homogenized with methylene chloride and centrifuged. Continuous liquid-liquid extraction, steam distillation, and microextraction likewise gave quantitative recoveries for most of the model compounds from spiked water, but these same techniques were
Gas chromatograph or GUMS
1-mL concentrate of phenols
not very satisfactory for sludges. Comparison of various cleanup techniques indicated that silica gel chromatography was slightly superior to chromatography on Florisil or BioBeads SX-3.
Purge-and-trap methodology One-liter glass bottles that serve both as trapping and purging vessels have been used in the analysis of benzene at the low part-per-trillion level in seawater. Robert Petty from the University of California-Santa Barbara refined the technique to allow determinations of benzene in the sea at natural levels. The sampling system has been tested at sea at depths of 5-200 m.An absolute detection limit for benzene was 0.2 ppt, but system blanks averaged about 2 ppt. A group of 11 samples showed a level of 13.8 f 1.8 ppt, indicating a remarkable degree of precision at these low levels. Using drinking-water samples, the Cincinnati EPA laboratory has made in-depth comparisons of Grab closedloop stripping analysis (GCLSA) with the Bellar purge-and-trap technique, acid/neutral extraction with methylene chloride, and XAD-2 resin ad-
sorption. GCLSA showed that drinking water samples varied greatly. R. G . Melton et al. of EPA's Cincinnati laboratory reported that once response factors and relative retention time factors have been determined, a sample can be concentrated in two hours, analyzed by capillary GC/MS in two hours, and computer-quantified in four hours. W. Coleman et al., also from EPA's Cincinnati laboratory, discussed the problems of automatic quantitation with CCLSA and capillary GC/MS. The key to success in using automatic quantitation is an accurate library of spectra, acquired on the user's instrument, for sample comparison and the ability to reproduce relative retention times and response factors. S. W. Krasner et al. from the Metropolitan Water District of Southern California in LaVerne also used the GCLSA technique to analyze for flavor- and odor-causing compounds in drinking water. Geosmin and 2methylisoborneol, two metabolites of actinomycetes and several species of blue-green algae, were detected at concentrations as low as 20 ng/L by capillary GC/MS. Volume 15, Number 2, February 1981 161
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Environmental Science d Technolog
In yet another application of X L S A , Jackson Ellington from the ithens EPA laboratory analyzed for irganic pollutants in sediments and in :omplex waste samples. A lake-bottom ediment, river sediments above and below a sewage plant outfall, and a ample of the sewage were concenrated through GCLSA and GC/MS. sediments were also spiked with ,adio-labeled compounds, and exraction efficiencies were determined vith Soxhlet, ultrasonic, Polytron honogenization, and conventional liquid :xtraction. R. L. Spraggins et al. from Radian Zorporation (Austin, Tex.) have nodified the conventional purgeind-trap methodology by constructing i high-temperature purging chamber .hat allows high-boiling organic polutants to be purged from water. An :xtension of this technique allows inalysis of solid samples such as ;ludge. Generally high recoveries were Ibserved; the technique is undergoing %rther evaluation with a wide rangeof matrices. W. C. Schnute and D. Smith of Finnigan Corporation (Sunnyvale, Calif.) described the development of a GC/MS system with automated software routines that identify and quanlify priority pollutants according to EPA’s Verification Protocol. The system incorporates a BellarLichtenberg purge-and-trap device with a fully automated GC/MS analyzer to perform the entire analysis with the touch of a single button. The reverse-search technique is used, and the list of target pollutants to be analyzed for can be expanded at will. The analyses can be performed in real time or in post-run processing. New instrumentation Robert Finnigan et al. of Finnigan Corporation and the University of Virginia described the use of two instruments to process rapidly the mass of GC/MS dats usually encountered in environmental sampling. The first, an organics-in-water analyzer, has been available for more than a year. It is simply a highly automated, relatively inexpensive quadrupole GC/MS with a computerized data system. The second instrument, however, a triple-stage quadrupole (TSQ) mass spectrometer, is new and has great promise. A TSQ/MS consists of tandem mass spectrometers, composed of an ion source and multiple mass analyzers, with a collision gas chamber between them. Because of this configuration, the technique is sometimes referred to simply by the abbreviation “MS/MS.” The great advantage of
MS/MS is that a sample is inserted directly into the ion source on a solids probe, without prior extraction or cleanup. Better quantification Over the five years since the first symposium on this subject was held, knowledge of specific organic pollutants in water has increased exponentially. Refinements of the techniques have made them better and more cfficient, but little “brand-new” methodology has been introduced for analyzing trace levels of organic compounds in water. Solvent extractions. resins, or purging techniques to concentrate the organics, and GC or HPLC with a variety of detectors to identify and quantify them, are still used. Attention is now turning more toward improving the accuracy and reliability of quantifications through stringent quality assurance programs and the use of internal, stable labeled standards. Because of the large numbers of samples now more or lcss routinely analyzed by GC/MS, there is also an emphasis on automated analyses through both hardware and software development. Finally, one new instrumental technique. MS/MS, offers promise of analyzing for specific compounds without the tedious and expensive concentration and separation requirements of conventional instrumental analysis. Note: Most of the papers mentioned will be published this summer by Ann Arbor Science Publishers. Inc.. in conjunction with the ACS Division of Environmental Chemistry, in a book with thesametitleas the symposium.
t
r
LH.Keilh is manager o/Radian CorporarionS Analyrical Chemistry Diuision and rhe corresponding laborarories in Austin. Tex.. and Sorramenro. Cali/. Prior lo joining Radian, he was a1 EPA’s Alhens. Ga.. Enuironmenral Research Lahorarory. where he helped 10 deuelop merhodolagy/or analysis ojorganic polluranrs in wafer and/or EPA’s priorirypolluranrs. He is pasf chairman o/rhe ACS Cenrral Texas Secrion and o/rhe Dicision o/Environmenral Chemisfry. and presenrly serves as !he dicision’s program chairman.
