1217
Anal. Chem. 1907, 59, 1217-1221
In general, large sample sizes can be obviated by the use of smaller analyte particles during formulation. Minimum weights, calculated by eq 8, are proportional to the cubed particle diameter. Therefore, a 50% reduction in diameter will lead to an &fold decrease in minimum weight. This effect is widely recognized and considered during the formulation development stages of projects that require minimal content uniformity variation among replicate samples of given size. Consequently, specifications may be established for particle size, or in other cases, it may become necessary to use formulation procedures other than dry powder blending.
LITERATURE CITED (1) Kratochvil,
938A.
Byron: Taylor, John
K. Anal. Chem. 1081, 53. 924A-
Harris, W. E.; Kratochvii, Byron Anal. Chem. 1974, 4 6 , 313-315. (3) Kateman, Writ: Pijpers, Frans W. "Quality Control in Analytical Chemlstry";Chemlcal Anelysls: Wiiey-Intersclence: New York, 1981; Voi. 60, Chapter 2. (4) Guidelines for Data Acquisition and Data Quality Evaluation in Environmental Chemistry Anal. Chem. 1980, 52, 2242-2249. (5) Ingamells, C. 0.; Switzer, P. Talanta 1073, 20, 547-568. (8) Ingamells, C. 0. Talanta 1074, 27, 141-155. (7) Ingamells, C. 0. Tahnfa 1976, 23, 263-264. (8) Ingamells, C. 0. Talanta 1078, 25, 731-732. (9) Kratochvil, Byron: Duke, M. John M.; Ng, Dennis Anal. Chern. 1086, 58, 102-108.
(2)
RECEIVED for review August 4,1986. Accepted December 19, 1986.
Recovery Studies of Volatile Organics in Sediments Using PurgeITrap Methods M. J. Charles' and M. S. Simmons* Environmental Chemistry Program, Department of Environmental a n d Industrial Health, The University of Michigan, Ann Arbor, Michigan 48109
Modlflcatlons of the purgaand-trap method have been used to analyze SOUS, sludges, and sedlments without thorough examination of compound and matrix effects. Experiments in this study were performed to examine the effect of sedlment type, analyte, and conductMty of the desorbing solution on the recovery of the purge-and-trap method. Only the type of cOmpOund was shown to affect the recovery of the methad. Overall recoveries for sorbed compounds on three different Sediments were 38% for chloroform, 48% for trlchloroethylene, and 54% for chlorobenzene.
Table I. Properties of Chloroform, Trichloroethylene, and Chlorobenzene property vapor pressure, Torr (25 "C) aqueous solubility, ppm (20 "C) (25 "C) Henry's law constant log octanol/water partition coefficient
Present address: California Public Health Foundation, P.O. Box
520, Berkeley, CA 94701-0520.
200"
740
8000'
12'
50OC
9300' 0.13"
llOOd
1.97e
2.29f
0.16d
2.84'
'
Reference 16. Reference 17. Reference 18. Reference 19. eReference 20. fReference21. a
Low molecular weight volatile chlorinated hydrocarbons (e.g., chloroform, trichloroethylene, and chlorobenzene) are common contaminants (1-5)of environmental interest because and they are mutagens, carcinogens, and teratogens (2,3,6,7) are not readily degraded. Studies addressing their migration in aquatic and terrestrial systems are much needed and require an analytical method applicable to all types of environmental matrices. Static and dynamic headspace methods for the analysis of liquids are well-developed (8-13).Modifications of these methods have been used on other matrices (e.g., soils, sediments, and sludges) without considering matrix effects. Characteristics that affect sorption such as particle-size distribution and organic carbon of soils/sediments can affect desorption. Desorption can also be affected by the analytes affiity for the sorbent. Comparing data among analytes, soils, or sediments results in erroneous conclusions about a compound's distribution throughout heterogeneous media. In addition, optimization techniques for water samples such as may altering the conductivity of the desorbing solution (14,15) not affect desorption when applied to other matrices. This study was undertaken to evaluate the recovery of representative volatile organics in sediment systems. It was
CHC13 CHCC13 CBHSC1
conducted in three phases. In phase I, three sediments were collected and characterized. With the differences among the sediments determined, phase I1 experiments were conducted to evaluate the experimental protocol and define conditions for sorbing the compounds on the sediments. These conditions were used in phase I11 to determine the effect of sediment and compound and the conductivity of the desorbing solution on the recovery of the method. Three test compounds were used in this study-chloroform, trichloroethylene, and chlorobenzene. These compounds were chosen to represent purgeables or volatile organics, and their aqueous solubilities, vapor pressures, and octanol-water partition coefficients are presented in Table I.
EXPERIMENTAL SECTION Reagents. Organic-freewater was prepared by passing doubly distilled water through activated carbon, 60/80 mesh (Anspec Co., Inc., Ann Arbor, MI) columns (43-cm i.d., 61-cm length). The water was purged of volatiles by heating to 90 OC and bubbling N2 through for 1 h. Potassium phosphate, potassium chloride, and NaOH were all purchased from Mallinckrcdt,Inc., Paris, KY. All solutions were prepared in organic-free water. Chloroform, trichloroethylene,and chlorobenzene were glass-distilled solvents (Burdick and Jackson, Muskegon, MI). Preparation of Standards and Blanks. All blanks were aliquots of organic-free water used that day for preparing
0003-2700/87/0359-1217$01.50/00 1987 American Chemical Society
1218
-
ANALYTICAL CHEMISTRY, VOL. 59,
Weigh sediment in purging bottle
+
Add 90 m l organic-free water
NO. 8,
APRIL 15, 1987 Spike sample
i
.c
I
Stir for 15 minutes
Centrifuge ai 3,000 r.p.m. for 30 minutes
Decant Supernatant
To remaining sediment add 90 m l organic-free water
Measure volume I
Figure 2.
Analyze sediment by purge-and-trap
Figure 1. Flow
Analyze supernatant by purge-and-trap
diagram of the experimental method.
standards or analyzing samples. Working standards composed of 148 ppm chloroform, 146 ppm trichloroethylene, and 110 ppm chlorobenzene were prepared daily. Standard solutions were prepared by injecting 10 pL, 100 pL, or 1 mL of the working standard into organic-free water (90 mL) in a purging bottle. These solutions contained 1.5-148 pg of chloroform, 1.5-146 pg of trichloroethylene, and 1.1-110 pg of chlorobenzene. Solutions of potassium chloride (0.01 and 0.001 M) and phosphate buffer (0.01 and 0.1 M KH,PO,) were prepared in organic-free water. The pH of the phosphate buffer solutions was adjusted to pH 7.0 with 1 N NaOH. Preparation of Spiked Samples. Hand-blown 100-mL purging bottles were constructed with 24/40 glass ground joints so sorption and desorption of spiked compounds were completed in the same container. The protocol used to spike sediment samples and sorb the compounds on the sediments is presented in Figure 1. A sediment subsample was weighed into a purging bottle. Organic-free water (90mL) was added to the bottle, 1 mL of the working standard solution was injected into the water layer (148.3 pg of chloroform, 146.4 pg of trichloroethylene, and 110.4 pg of chlorobenzene), and the container was capped with a 24/40 glass ground joint top. Unless otherwise indicated the mixture was magnetically stirred for 15 min and then centrifuged a t 4-10 "C and 30000 rpm (Sorvall RC-5B, Du Pont Instruments, Des Plains, IL) for 30 min. The supernatant (water layer) was decanted, measured in a glass-graduated cylinder, and then transferred to crimp-serum vials. All samples were brought to 25 "C in a water bath prior to analysis. Purging. A schematic of the purging device is presented in Figure 2. Coarsely fritted gas-impingers with 24/40 ground-glass joints (University of Michigan, Department of Chemistry, Ann Arbor, MI) were inserted into the purging bottle. A 13-mm J-shaped trap filled with 9.5 mm of Tenax-GC porous polymer 60/80 mesh (Anspec Co., Ann Arbor, MI) and silanized glass-wool plugs was attached to the gas exit side of the gas impinger via a tube reducer (Swagelok, Farmington Hills, MI) and silicone tubing (Cole-Parmer, Chicago, IL). A line connected to a flowmeter to control the flow of N2into the container was attached to the other end. Water samples were purged for 11 min and sediment samples were purged for 24.75 min at a flow rate of 40 mL/min. Previous experiments showed that this flow rate and these times were optimum for purging compounds from waters and sediments. All samples were magnetically stirred during purging. Thermal Desorption of Traps and Gas Chromatographic Conditions. Flash heaters were constructed from 250-mL
Schematic diagram of purging apparatus.
graduated cylinders (4.5-mm i.d.) cut to a height of 10 mm, wrapped with beaded glass-wire (Marsh Beaded Heaters, Lake Jackson, TX), and insulated with several layers of asbestos. The temperature of the heater was controlled with a powerstat (Staco, Inc., Dayton, OH) and adjusted so that the inner temperature of the heater was maintained at 250 "C. A Hewlett-Packard gas chromatograph (Model 5730A) was modified to accommodate thermal desorption of the trap. A four-way port valve and a three-way port ball valve (Whitey Co., Highland Heights, OH) were installed. The four-way port valve was used to direct the N2 carrier gas from the GC column to the trap. The three-way port valve was used as an on/off valve to control the gas entering the trap. This arrangement eliminated any back pressure contamination of the lines to the trap while allowing N2 to flow through the trap onto the GC column. After the trap was purged, the trap was attached to the GC by a female connector (1/4-in. o.d., l/s-in. (i.d.) rethreaded to fit the injection port of the instrument and a 1/4-in.-o.d.nut (Swagelok,Farmington Hills, MI). Compounds were desorbed from the trap at 250 "C for 4 min while the GC oven was maintained a t 50 "C. The compounds were directed onto a 6-F glass column (1/4-in.o.d., 4-mm i.d.) packed with 60/80 Carbopack B/10% SP-lo00 (Supelco, Inc., Bellefonte, PA). After desorption of the compounds onto the column, the GC oven door was closed and the oven was temperature-programmed to increase from 100 to 200 "C at 8 "C/min with a flow rate of 60 mL/min. Analysis of Blanks and Standards. Two blanks were analyzed for every 10 samples. One blank was organic-free water used in the analyses and the other was a method blank treated and processed as a sample to check for cross-contamination. Three external standards representing low, mid, and high levels of the compounds were analyzed a t the beginning and end of day. Additional mid-level standards were analyzed so that the standards comprised 20% of all the samples. The mean response factor calculated was used to quantitate the amount (micrograms) of analyte purged. Sediment Samples. Surficial sediment samples were collected from Third Sister Lake, Ann Arbor, MI, but using an Ekman dredge. After collection, the samples were transferred to 1-gallon wide-mouth glass Mason jars. In the laboratory, samples taken from the same location were homogenized and then redistributed to their containers. These samples were then stored a t 4 "C. Characterization of the Sediment Samples. Particle-size fractionation of the sediments was completed by wet-sieving and pipet analysis procedures (22). The percent total and organic carbon of the sediments were analyzed by dry combustion in a Packard (Model 185B) carbon-hydrogen-nitrogen (C-H-N) commercial analyzer. The organic carbon was measured after acidwashing the samples with 0.1 N HC1 to remove the inorganic carbon. The inorganic carbon was calculated by difference be-
ANALYTICAL CHEMISTRY, VOL. 59,
NO. 8,
APRIL 15, 1987
1219
Table 11. K , and Desorption vs. Mixing Time 70 desorbed
K, sediment
time, min
CHC13
CHCC13
C6H5C1
CHC13
CHCCl:,
CGHbC1
1 ( n = 2)
2 4 16 2 4 16 32 2 4 16 32
29 f 9 21 f 5 15 f 1 2fl I f 1 2f1 2fl 6f1 9f3 8f8 2f2
40 f 5 45 f 7 39 f 0 3fl 3fl 3fl 3fl 14 f 1 8fl 19 f 14 14 f 4
59 f 1 62 f 1 64 f 3 4f2 3fl 3f2 6f1 22 f 9 27 f 15 34 f 6 24 f 13
58 f 11 79 f 23 90 f 14 40 f 10 39 f 9 52 f 16 38 f 15 41 f 1 40 f 14 47 f 20 35 f 6
47 f 3 57 f 8 55 f 6 25 f 7 22 f 4 32 f 5 28 f 6 32 f 4 44 f 11 30 f 4 25 f 4
52 f 8 47 f 10 48 f 5 25 f 8 30 f 14 44 f 21 23 f 5 36 f 6 27 f 20 34 f 6 29 f 8
2 ( n = 3)
3 ( n = 2)
tween the total and organic carbon. The minerals in the five sediments were identified by X-ray diffraction obtained by using a Phillips APB3000 X-ray diffraction system. Conductivity Measurements. The conductivity of the sediment-water mixtures was measured by using a YSI Model 31 conductivity meter and a conductivity electrode (Yellow Springs Instrument, Inc., Yellow Springs, OH). Statistical Analyses. The data were analyzed by a variety of univariate and multivariate statistical tests. The univariate procedures employed were analysis of variance (ANOVA) and the Scheffe method of multiple comparisons. The multivariate procedures used were the profile analysis and the repeated measures test. All these tests were statistical programs available through Michigan Interactive Data System (MIDAS) and/or the Michigan Terminal System (MTS) of the University of Michigan.
Particle-size Distribution and Organic C a r b o n in Sediments 100,
Ea crov.1
m
Sand
Silt
cloy
0orpmis camon
RESULTS AND DISCUSSION Phase I. Sediment Characterization. Sediments were characterized according to their particle-size distribution and organic carbon content. Both these parameters have been shown to affect sorption of organic compounds on sediments (23-26) as well as desorption. The differences among the sediments is visually evident from a plot of the mean and standard deviation of the percent gravel, sand, silt, clay, and organic carbon vs. sediment (Figure 3). Sediment 1 contains the greatest proportion of silt (84%) and organic carbon (12%) with small amounts of sand (16%)and no clay. Sediment 2 is almost totally composed of sand (91%) and sediment 3 contains sand (22%), silt (55%),and clay (33%). By Folk’s classification, sediment 1 is a silt/sandy silt, sediment 2 is a gravelly sand, and sediment 3 is a sandy-mud/mud. Overlapping textural classes (i.e. between a silt and sandy silt) resulted due to errors in wet-sieving. Despite these errors, the sediments were shown to be statistically different (a = 0.05) by ANOVA and the Scheffe method of multiple comparisons. Additional sediment characterization showed that these samples were primarily composed of quartz (>85%) with less than 1% inorganic carbon. This information is important when considering sorption and desorption processes. A high quartz content shows that the clay content of sediment 3 is a size distinction, not an indication of the presence of clays. The low inorganic carbon shows that organic carbon is the primary component. Phase 11. Evaluation of Experimental Protocol a n d Sorption/Desorption Conditions. Due to the volatility of the compounds, experiments were conducted to evaluate losses due to mixing, centrifuging, or decanting of the aqueous phase. Water samples were analyzed directly after treatment according to the experimental protocol. An estimate of losses associated with the aqueous phase was calculated as the sum of the losses associated with mixing, centrifuging, and transferring the supernatant. For the sediment phase, losses due to sample transfer were excluded. Estimated losses from the aqueous phase were 24% for chloroform, 28% for tri-
I
Sediment
I
Figure 3. Characteristics of sediment samples.
chloroethylene, and 25% for chlorobenzene. Losses associated with the sediment phase were 18% for chloroform, 11% for trichloroethylene, and 23% for chlorobenzene. These values are acceptable considering the importance of mixing to separate the aqueous and sediment phases and the reported losses of 4-16% for sample transfer (27). These estimates are probably high since rates of vaporization will be less for sorbed compounds than those in water. The effect of mixing time and the weight of sediment on sorption/desorption were also evaluated. These variables are important because they can affect partitioning of the compounds between the sediment and aqueous phases. The mixing time for the system was optimized to establish equilibrium conditions. Since the partition coefficient (K,) for hydrophobic compounds decreases as a function of sorbent concentration (28,29),a sample weight or concentration was chosen that corresponds to the portion of the curve where small changes in K , are observed. The effect of sediment weight was also of interest since most laboratories differ in their sample size used for analyses. The effect of mixing time was determined by comparing the K,) and percent desorbed after mixing for 2, 4, 16, and 32 min. The data presented in Table I1 were statistically analyzed by ANOVA and the Scheffe method of multiple comparisons. No differences (cy = 0.05) were observed due to mixing from 2 to 32 min. Equilibration therefore occurs rapidly between the two phases. An arbitrary time of 15 min was used in subsequent experiments. The effect of sediment weight (1-50 g wet-weight) was determined by comparing the K, and the percent sorbed and desorbed. The results presented in Table I11 show that the partition coefficients, as observed for more hydrophobic compounds rapidly decrease and then level off as the weight
1220
ANALYTICAL CHEMISTRY, VOL. 59, NO. 8, APRIL 15, 1987
Table 111. K , , Sorption, and Desorption vs. Sediment Weight KP
70 desorbed
% sorbed
sediment
dry weight, g
CHC13
CHCC1,
C6H5C1
CHC1,
CHCC1,
C6H6Cl
1
0.20 0.79 1.68 1.96 3.35 3.61 6.12 6.79
202 53 26 26 16 18 9 7
235 55 41 37 27 31 16 16
215 67 48 59 40 45 26 23
32 33 33 37 38 42 42 49
35 34 43 46 51 56 56 61
33 38 47 54 60 65 67 69
0.94 2.16 5.92 12.27 14.93 27.11 34.79
31 4 4 3 1 1 1
32
12 5 21 2 3 2 1
25 9 21 29 12 11 23
25 17 31 32 19 27 31
0.48 2.07 4.42 5.39 8.00 8.17 17.42
74 15 9
9a 20 16 14 12 16 2
87 27 21 27 17 17 3
28 25 30 24 41 39 25
34 31 43 45 54 54 35
2
3
a
7 c
1
1
a
7 3 1 1 1
of the sediment increases. For sediment 1, 2, and 3 and K , decreased, respectively, from 202 to 7 , 31 to 1,and 74 to 1 for chloroform; 235 to 16,32 to 1,and 74 to 1for trichloroethylene; and 215 to 23, 1 2 to 1, and 87 to 3 for chlorobenzene. No trends in sorption or desorption were evident due to the sediment weight. Data derived from different sample weights can therefore be compared. Concern arises however due to the large range in values reported, particularly for desorption. This variability could be due to the experimental losses previously discussed or inherent to the purge-and-trap method. This variability will be discussed later. Phase 111. Effect of Conductivity on Desorption. In these experiments the conductivity ( p ) of the desorbing solution was varied prior to purge-and-trap analysis of the sediments by adding either organic-free water ( p = 80 pmhos/cm), 0.01 M KH2P04( p = 1400 pmhos/cm), or 0.1 M KHzP04 ( p = 12 000 pmhos/cm). These experiments were conducted in a random fashion and were replicated four times for each treatment (conductivity) and sediment. Analyses of the data were performed by using multivariate and univariate tests. The multivariate procedures are omnibus tests and were used for comparing variables within a sediment type. This approach was taken because the data were derived from repeated measures of the same sediment (Le., replicates were subsamples from the same batch of sediment). These tests were used to determine if desorption was affected by conductivity and if and how sorption or desorption differed among the compounds for each sediment. Hypotheses were rejected at significance levels less than 0.05. The conditions prior to treatment were shown to be constant by multivariate profile analyses of the Kpand the percent sorbed data. This test, also performed on the data regarding the desorption (refer to Table IV), showed that conductivity had no effect in desorbing compounds on sediments 1 and 3. An interaction was observed however for sediment 2. An interaction in this context means that the profiles were not parallel. The test is based on additive model requiring parallel profiles, which is not valid for sediment 2. No effect of conductivity is however observed by comparing values for sediment 2. Other investigators have noted a slight decrease in recovery due to salting-out of the compounds (30,31). In this study, no decrease in desorption was noted as the conductivity
CHC1,
CHCC1,
C6H5C1
104
10 45 45 44 66 51 72 69
36 71 62 50 78 59 74 57
12 14 5a 24 33 39 22
5 20 15 21 63 103 71
4 21 11 23 40 40 53
37 32 11 51 42 42 127
32 37 50 62 62 61 42
7 15 29 32 36 37 50
a ia
19 24 37 14 44 49 28
11 37 41 43 68 53
ai
31 3a 35 38 32
Table IV. Recovery of Purge-and-Trap Method vs. Conductivity of Desorbing Station
sediment
conductivity, pmhos/cm
% desorbed
CHCl,
CHCC1,
C6H&1
1
12 000 1400
ao
55 f 6 46 f 3 56 f 29
47 f 7 40 f 7 44 f 8
65 f 6 58 f 17 ao 45
2
12 000 1400 80
56 f 33 58 f 17 46 f 16
33 f 13 37 f 7 38 17
*
51 f 16 64 f 7 4a f 11
12 000 1400 80
32 f 4 2a i 4 32 f 1
33 f 3 30 f 1 34 f 1
49 f 10 54 5 i a 45 f 14
3
*
of the desorbing solution was increased. Salting-out of the compounds was prevented by actively stripping the compounds from solution. Further multivariate analysis of the data showed that recovery of the method varies according to the analyte. Desorption of the compounds was expected to be greater for compounds having higher vapor pressures and aqueous solubilities (chloroform > trichloroethylene > chlorobenzene). Instead, statistical analysis of the data showed that, overall, desorption followed the order chloroform = trichloroethylene < chlorobenzene. The differences in the values, however, considering the relative standard deviation of the means, is small. Any differences may be due to characteristics of the organic carbon that make it a better solvent for chloroform and trichloroethylene than for chlorobenzene. Overall, desorption is not affected by sediment type. Even though a decrease in desorption for chloroform on sediment 3 is indicated when compared to other samples (Table IV), univariate analysis of the data by ANOVA and the Scheffe method of multiple comparisons showed that these differences were not significant a t a 95% confidence interval. Other researchers have reported slight differences according to matrix type (31). The recovery of the purge-and-trap method for chloroform, chlorobenzene, and trichloroethylene in this study compared to those reported by other investigators is shown in Table V. In other studies, compounds sorbed on the sediments were not differentiated from those not sorbed. In the investigation
ANALYTICAL CHEMISTRY, VOL. 59, NO. 8, APRIL 15, 1987
Table V. Summary of Recoveries for Purge-and-Trap Methods (% Relative Standard Deviation) compound sample
CHC13
CHCC13
sedimenta sandy l o a m soilb clay soilb clay soilb lake sedimentb river sedimentb sandy-silt sedimentc gravelly-sand sedimentC mud sedimentc
88 i 24 117 i 4
73 i 23
a Reference
32.
229 f 80 275 i 52 154 i 55 52 f 16 53 i 22 33f9
Reference 33.
44 f 7 36 i 12 33f7
C8H5Cl 97 f 9 92 i 2 102 f 53 106 i 12 87 f 7 67 f 27 54 i 13 48 f 14
T h i s study.
conducted by Michael et al. (28,34)compounds were spiked into a soil-water slurry, equilibrated, and then analyzed by purge-and-trap. In the study conducted by Hiatt (35),compounds dissolved in methanol were spiked on the sediments. Volatile losses in these studies should have been less since the aqueous and sediment phases were not separated. Yet, the relative standard deviation around the mean is rather large ( 4 4 5 % ) . Thus a large variability occurs when the purge and trap method is applied to soils and sediments. Variability associated with the extraction process may be less. Hiatt (35) has reported relative standard deviations of 5 2 2 % for vacuum extraction and 12-13% for purge-and-trap with thermal desorption.
CONCLUSION The results of this study show that neither sediment weight, type, nor the conductivity of the desorbing solution have an effect on the recovery of the purge-and-trap method. The ability of the method to desorb compounds on sediments however is affected by the particular analyte. Cross comparisons of data are valid for different sediments and sample weights but not for different analytes. The mean overall recovery of the method in this study was 38% for chloroform, 48% for trichloroethylene, and 54% for chlorobenzene. These values are recoveries of sorbed compounds. Reproducibility is a problem when the purge-and-trap method is applied to sediments. This variability may be less by other methods that use more radical means of extracting the compounds from the sediments. Further studies are needed to compare these methods.
ACKNOWLEDGMENT We thank Ronald Rossmann, Russell Moll, Kevin Given, Steve Holodnick, and Bill Frez for technical assistance in the project, and M. Anthony Schork for his assistance in the statistical analyses of data. We also acknowledge the help of Dave Hunsche, Mary Weed, and Alice E. Norberry in the preparation of the manuscript.
1221
LITERATURE CITED (1) Lillian, D.; Slngh, H. 8.; Appleby, A.; Hobban, L.; Arnts, R.; Gompert, R.; Hague, R.; Tooney, J.; Kazazis, J.; Antell, M; Hansen, D.; Scott, D. Environ. Sci. Technol. 1975, 9 , 1042-1048. (2) McConneil, 0.; Ferguson, P. M.; Pearson, C. R. Endeavour 1975, 3 4 , 13-18. (3) Merian, E.; Zander M. I n Handbook of Environmental Chemistry; Hutzinger, O . , Ed.; Springer-Verlag, New York, Voi. 3, Part B, pp 117-1 61. (4) Giger, W.; Molnor-Kubica, E. Bull. Environ. Contam. Toxicol. 1978 19, 475. (5) Tucker, R. K. New Jersey Department of Environmental Protection, Office of Science and Research, Trenton, NJ. (6) Fishbein, L. Mutation Res. 1976, 32, 267-308. (7) Fishbein, L. Science TotalEnviron. 1979, 11, 163-195. (6) Bellar, T. A.; Lichtenberg, J. J.; Kroner, R. C. J. Am. Water Works Assoc. 1974 66, 703-706. (9) Budde, W. L.; Eichelberger, J. W. Organics Analysis Using Gas ChromatwraDW/1cbss SDectrometw; Ann Arbor Science: Ann Arbor, MI, 1980: p'39. Grob, K. J. Chromatogr. 1973 8 4 , 243-255. Grob, K.; Grob. K., Jr.; Grob, G. J. Chromatogr. 1975, 106, 229-245. McGuire, J. M.; Webb, R. G. I n Water Oualiv Measurement; Mark, H. B., Matson, J. S.,Eds.; Marcel Dekker: New York, 1981; pp 1-31. (13) Mleure, J. P.; Mappes, G. W.; Tucker, E. S.;Dietrich, M. W. I n Identification and Analysis of Organic Pollutants in Water; Kieth, L. A,, Ed.; Ann Arbor Science: Ann Arbor. MI. 1976: o 113-133. (14) Dietz, E. A :: Singley, F. Anal. Chem'. 197S,751, 1809-1814. (15) Friant, S.;Suffet, I. H. Anal. Chem. 1979, 51, 2167-2172. (16) Dilling, W. L.; et al. Environ. Sci. Technol. 1975, 9 , 833-836. (17) Verschureren, K. Handbook of Environmental Data on Organic Chemicals; Von Nostrand, Reinhold: New York, 1977. (18) O'Connor, D., I n Modelling of Toxic Substances in Natural Water Systems; Manhattan College: New York, 1980. (19) Mackay, D. et al., Report EPA 600/3082-019, 1962. (20) Hansch, C. et al. J. Med. Chem. 1975, 18, 546-548. (21) Leo, A. et ai. Chem. Rev. 1971, 71, 525-616. (22) Royse, C. F., Jr. I n Introduction of Sediment Analysis; Arizona State University: Tempe, AZ, 1970; 180 pp. (23) Hutzler, N. J. Londo, L. J.; Crittenden, J. C. I n Proceedings of the ASCE Environmental Engineering, Division Specialty Conference, Minneapolis, MN, July 14-16, 1982. (24) Richter, R. 0. Abstracts of Papers, 186th National Meetlng of the American Chemical Society, Washington, D.C., Aug. 28-Sept. 2, American Chemical Society: Washington, DC, 1983. (25) Suess, E. Geochim. Cosmochim. Acta 1970, 3 4 , 157-160. (26) Chiou, C. T., Peter, L. J.; Freed, V. Science 1979, 206, 831-832. (27) Bickford, B.; Bursey, J.; Michael, L.; Pellizari, E.; Porch, R.; Rosenthal, D.; Sheldon, L.; Sparacino, C.; Tomer, K.; Wisemen, R.; Yung, S.; Gebhart, J.; Rando, L.; Perry, D.; Ryan, J. Preliminary Draft Report Master Scheme for the Analysis of Organic Compounds in Water. Part 11. Experimental Development and Results; USEPA: Athens, GA, 1980. (28) O'Connor, D. J.; Connoily, J. P. Water Res. 1980, 14, 1517-1523. (29) Weber, W. J., Jr. Voice, T. C.; Pirbazi, M.; Hunt, G. E.; Ulanoff, D. M. Water Res. 1983, 17, 1443-1452. (30) Michael, L. C., Turlingron, J. M.; Zweidinger, R. A,; Pelizzari, E. D. reprint of presentation given at the 183rd National Meeting of the American Chemical Society, Las Vegas, NV., March 28-April 2; American Chemical Society: Washington, D.C., 1982. (31) Brazell, R. S.;Maskarinec, M. P. HRC C C , J . High Resolut. Chromatogr. Chromatogr. Commun. 1981, 4 , 404-405. (32) Hiatt, M. H. Anal. Chem. 1961, 5 3 , 1541-1543. (33) Michael, L. C. et ai. reprint of presentation given at the 186th National Meeting of the American Chemical Society, Washington, D.C.; American Chemical Society: Washington, D.C., 1983. (34) Michael, L. C.; Thomas, K. W.; Sheldon, L. S.; Zweidinger, R. A,; Pelizzari, E. D. reprint of presentation given at the 166th National Meeting of the American Chemical Society, Washington, D.C., Aug. 28-Sept. 2; American Chemlcai Society: Washington, D.C. 1963. (35) Hiatt, M. H. Anal. Chem. 1981, 53, 1541-1543.
RECEIVED for review October 14, 1985. Resubmitted September 22, 1986. Accepted December 23, 1986.
