Document 8RgamVD0v8Bbng4qJEdzE4LKB

Edmondson Road, uc ionces and ty of North Carolina 4 tther Metabolism . of Environmental Farland rapid publication of l contamination and a the introduction, *'C,ds). In order to scripts ought to be on the back Inside ii. particularly with jhheation, Complete will be published in I'tmation potentially Y detailed so as to stable for inclusion >r research workers t and who welcome nnuelty as demand uo. New York, N.Y. i28 4- .75 postage persona/ use only. per volume, ik Inc. Rapid Separation of Polychlorinated Biphenyls from DDT and Its Analogues on Silica Gel by Diane Snyder* and Robert Keinert U.S, Fish and Wildlife Service Great Lakes Fishery Laboratory Ann Arbor, Michigan 48107 Polychlorinated biphenyls (PCB's), which are used in indus try worldwide (1), have been found as residues in numerous wild life species '(2-7) . Because of the similarity in chemical char acteristics, PCB compounds interfere with gas liquid chromato graphic (GLC) analysis of certain chlorinated hydrocarbon insec ticides (8). In the present study, we sought a rapid microanalytical procedure for separation of PCB's from DDT and its analogues before analysis with GLC. A small silica gel column was found to be suitable for removing two of the Aroclor series of PCB's (1254 and 1260) from DDT and its analogues. Materials Silica gel used for the columns was grade 950 activated des iccant, 60-200 mesh, from the Davison Chemical Division of W. R. Grace, Baltimore, Maryland. Pentane and benzene, distilled in glass grade, were from Burdick and Jackson Laboratory, Inc., Muskegon, Michigan. Commercial PCB preparations containing 54 and 60 percent chlorine (Aroclor 1254 and 1260) wefe from the Monsanto Organic Chemicals Division of the Monsanto Co., St. Louis, Missouri. Standards for DDT and its analogues (DDT, DDD, DDE) were from the U.S. Public Health Service Pesticides Repository, Pesticide Research Laboratory, Perrine, Florida. The Method Transfer silica gel from a freshly opened can to a glass stoppered bottle and add enough pentane to cover the silica gel with at least 12 mm of pentane. If the silica gel has been pre viously exposed to air, reactivate it by placing it in an oven at 200 C for 8 hours before mixing it with the pentane. Quickly add the mixture of silica gel and pentane to a glasswool stoppered column (1.0 cm ID x 20 cm long). A useful tool for packing the column is a disposable pipette from which the narrow portion of the tip has been removed. Small amounts of silica gel 1/ Present address: Johns Hopkins School of Hygiene, Department of Population Dynamics, Baltimore, Maryland. Bulletin of Environmental Contamination & Toxicology, Vol. 6, No. 5,1971, published by Springer-Vcrlag New York Ine. 027587* TOWOLDMONOQ54289 . are drawn into the pipette with a rubber bulb, and expelled into the column. Gentle tapping of the column facilitates packing. Always keep enough pentane in the column to ensure that the silica gel being added will filter through the pentane, thus eliminating air bubbles. The column must be free of air bubbles or breaks in the packing to ensure proper separation of the DDT complex from the PCB's. A length of 7.7 cm (about 3 g dry weight) of silica gel is required for each column. Wash the column with 5 ml of pentane. Place 1 ml of sample in pentane or hexane on the column. Rinse the tube which contained the sample twice with 1-ml portions of pentane and place the rinse on the column. After the sample and rinse have been absorbed, collect the following solvent fractions separately in two 50-ml tubes: Fraction Solvent Ml collected Chemical eluted A Pentane 1-38 PCB's B Benzene 39 - 75 DDT and its analogues Concentrate each fraction to the desired volume and analyze with GLC. If the amounts of PCB or insecticide put on the column are large, poor separation results; therefore, only the amounts necessary for determination by GLC analysis should be passed through the column. Operating conditions for GLC and the methods for extraction and cleanup of fish samples before the extracts are placed on the silica gel column were described by Reinert (9). Concentrations of Aroclorsare determinedby planimetric readings of the GLC chromatograms. Areas for all the PCB compo- nents collected in the pentane fraction are compared with the areas for known amounts. This method yields a standard curve that is linear on semilog paper. . Efficiency of the Method Efficiency of the silica gel column was measured by deter mining percentage recoveries when known amounts of Aroclors 1254 and 1260 and the DDT complex were washed through the column (Table 1). Fraction A recoveries for 1254 and 1260 averaged 97 and 102 percent, respectively. No peaks with retention times similar to those of DDT and its analogues were found in fraction B. Measured amounts of Aroclors 1254 and 1260 were added to hexane extracts from fish. The fish--one coho salmon, Oncorhynchus kisutch, and two lake trout, Salvelinus namaycush, from Lake Michigan--contained substantial concentrations of DDT and its i t ! : ' ' ; , | \ ; 1 j j I | : ; ; j j * , *' ' j } ; : ; ( j Percents*: and t_h Fraction j chemical Fraction A Aroclor 1 Aroclor 1 Fraction B pp DDE op DDT pp DDD pp DDT analogues, analyzed wcolumn effi its analog-. cleanup of 1254 are s. The s separates Little pri the small taneously achieved i tative rec 0275075 TOWOLDMONOQ54290 TABLE 1 Percentage recoveries for known amounts of Aroclor 1254 and 1260 and the DDT complex after separation on silica gel columns Fraction and chemical Concentration (lX10~8g/ml) Humber of trials Percentaqe recovery Average Range Fraction A Aroclor 1254 50.0- 100.0 15 97 86-118 Aroclor 1260 50.0 13 102 80-130 Fraction B pp DDE op DDT pp DDD pp DDT 4.0- 10.0 0.5- 10.0 0.5- 10.0 4.0- 10.0 15 12 12 12 89 72-110 93 78-114 96 83-114 97 72-118 analogues. Three samples of each of the spiked extracts were analyzed with GLC after separation on silica gel. The silica gel column effectively separated Aroclor 1254 and 1260 from DDT and its analogues in extracts from fish (Table 2). Chromatograms taken at various stages during the silica gel cleanup of the hexane extract of a lake trout spiked with Aroclor 1254 are shown in Figure 1. The silica gel column described here rapidly and efficiently separates the two Aroclors tested from DDT and its analogues. Little prior preparation of the silica gel is needed. Because of the small size of the columns, numerous samples can be run simul taneously on individual columns in a small area. Separation is achieved in about 1 hour. Reproducibility of results and quanti tative recoveries from samples were good. 387 0275876 TOWOLDMONOQ54291 TABLE 2 Percentage recoveries from silica gel columns for Aroclors 1254 and 1260 and the DDT complex in hexane extracts from coho salmon and lake trout Species and chemical component Percentaqe recovery Concentration Fraction A Fraction B* {1X10 g/ml) Trial Trial Trial Trial Trial Trial 1 23 123 Coho salmon Aroclor 1254 pp DDE op DDT pp DDD pp DDT Lake trout Aroclor 1254 pp DDE op DDT pp DDD pp DDT Lake trout Aroclor 1260 pp DDE op DDT pp DDD pp DDT 50.0 8.0 1.0 1.0 4.0 50.0 13.0 1.0 2.0 6.0 50.0 10.0 1.0 1.0 5.0 108 108 108 ------- --- 90 90 100 ------- --- 130 - - 120 - - 110 - - - -- 100 72 100 100 94 62 100 100 85 125 114 100 --- 96 76 100 80 100 80 87 87 67 91 91 82 --- 80 90 110 83 100 100 100 83 83 89 89 no * Percentage recoveries for the DDT complex were calculated by comparing the amounts of insecticide found in the hexane ex tracts from fish with the amounts found after the separation procedure on silica gel columns. UJ Q a 0. ol < O.P'DDT 0275877 TOWOLDMONOQ54292 M MM Mo Ow Oo Ho | 0275878 Figure 1. Chromatograms of the hexane extract of a lake trout before and after the addition of C.5 yg of Aroclor 1254. (A) Hexane extract of a lake trout after the initial cleanup (9), showing DDT and its analogues. (B) Hexane extract after addition of 0.50 ug of Aroclor 1254. (C) Pentane fraction of the hexane extract after cleanup on silica gel, showing Aroclor 1254,. (D) Benzene fraction of the hexane extract after cleanup on silica gel, showing DDT and its analogues. TOWOLDMON0054293 References (1) C. G. GUSTAFSON. Environ. Sci. and Tech. 10, 814 (1970) (2) T. W. DUKE, J. F. LOWE, AND A. J. WILSON, JR. Bull. Environ Contain, and Tox. 5., 171 (1970) (3) A. V. HOLDEN, and K. MARSDEN. Nature. 219, 1274 (1967) (4) D. C. HOMES, J. H. SIMMONS, and J. O'G. TATTON. Nature. 216, 227 (1967) (5) S. JENSEN, A. G. JOHNELS, M. OLSON, and M. GOTTERLIND. Nature. 224, 247 (1969) (6) J. H. KOEMAN, M. C. TEN NOEVER DE BRAUW, and R. H. DE VOS. Nature. 221, 1126 (1969) (7) R. W. RISEBROUGH, P. RIECHE, D. B. PEAKALL, S. G. HERMAN, and M. N. KIRVEN. Nature. 220, 1098 (1968) (8) L. REYNOLDS. Bull. Environ. Contam. and Tox. , 128 (1969) (9) R. E. REINERT. Pest. Monitoring J. 3_, 223 (1970) I l> One of insecticide of animals, constant th reaches a p and excreti mates intak of excretic lizing enzy enzymes car. stances inc carbon has because of The pu of detoxica dieldrin rt Female ment. The Laboratory lism cages tate sepan The l: six groups 0 and 1 g body weigh mixed cont a tracer, times the Conduct requiremen Dakota Sta 2 Supplie 2 ppm of t 1,4,4a,5,6 (HEOD). Bulletin of En* Vol. 6, No. S, 1` 0275079 TOWOLDMONOQ54294