Gas-chromatographic determination of pesticide residues after clean-up by gel-permeation chromatography and mini-silica gel-column chromatography

1981 ◽  
Vol 307 (4) ◽  
pp. 257-264 ◽  
Author(s):  
Wolfgang Specht ◽  
Monika Tillkes
1998 ◽  
Vol 81 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Mona Syhre ◽  
Gudrun Hanschmann ◽  
Ralf Heber

abstract A powerful cleanup procedure for determination of chlorinated pesticides and poly chlorinated biphenyls (PCBs) in difficult agricultural matrixes like feeds or crops was developed to eliminate the interferences in chromatograms obtained by gas chromatography with electron capture detection. The adsorption material used was ENVI-Carb, a graphitized nonporous carbon material. This procedure proved to be more reliable than the established cleanup procedure, which uses gel permeation chromatography and silica gel cartridges. Because ENVI-Carb cleanup delivers clear, colorless eluates with no interferences, chlorinated pesticides and PCBs may be detected at levels as low as 0.0004 mg/kg for monitoring purposes. Accuracy was validated through a series of recovery experiments.


1981 ◽  
Vol 64 (2) ◽  
pp. 282-286 ◽  
Author(s):  
B Garth Burns ◽  
Charles J Musial ◽  
John F Uthe

Abstract A new, simple, and rapid cleanup procedure is described for di-2-ethylhexyl phthalate (DEHP) residues in fish lipids. Extracts are chromatographed on small alumina:sulfuric acid-impregnated alumina (layered) columns after gel permeation chromatography of the fish lipid extracts on BioBeads SX-3. Quantitative analyses were carried out by electron capture gas chromatography using 2 columns. Spiked DEHP recoveries varied from 79.3% in mackerel to 86.1% in herring. DEHP concentrations were determined in plaice, eel, redfish, herring, cod, and mackerel tissues and ranged from trace (<0.001 µ/g) to approximately 10 µ/g (wet wt basis). Ethanolic KOH saponification of the purified DEHP fraction, resulting in the disappearance of the DEHP peak, was used as a confirmatory test. Limited studies with dibutyl, di-n-heptyl, and diethyl phthalates suggest that the method can be made more versatile.


1991 ◽  
Vol 74 (2) ◽  
pp. 394-399 ◽  
Author(s):  
Dirk M Holstege ◽  
David L Scharberg ◽  
Elizabeth R Richardson ◽  
Gregory Möller

Abstract A multiresidue screen for quantitative determination of 43 organophosphorus insecticides In 5 g of plant and animal tissues Is described. The organophosphorus insecticides are extracted with methanol-dichloromethane (10 + 90, v/v) and cleaned up using automated gel permeation chromatography with hexane-ethyl acetate (60 + 40) eluant and in-line silica gel minicolumns. Concentrated extracts are analyzed by gas chromatography with flame photometric detection. The method recovers 43 organophosphorus insecticides in the range of 72 to 115%. Analysis of fortified bovine liver (n = 5) shows an average 95.9 ± 4.8% recovery at the 0.05 μg/g level and 93 ± 3.8% at the 0.5 μg/g level. Analysis of fortified bovine rumen content (n = 5) shows an average 98 ± 4.2% recovery at the 0.1 μg/g level and 98.7 ± 2.8% at the 1 μg/g level. Method detection limits ranged from 0.01 to 0.05 μg/g for the compounds studied using a nominal 5 gram sample.


1993 ◽  
Vol 76 (6) ◽  
pp. 1317-1322 ◽  
Author(s):  
Paul Armishaw ◽  
Roderick G Millar

Abstract Methods using a commercial sweep codistillation apparatus, gel permeation chromatography (GPC), and Florisil column adsorption chromatography were compared as cleanup techniques for the determination of organochlorine pesticide residues in animal fats by Megabore capillary gas chromatography with electron capture detection. Animal fat that had been previously found to contain no detectable organochlorine residues was spiked with 17 organochlorine pesticides at levels ranging from 0.1 to 0.4 mg/kg and cleaned up by each of the 3 techniques. Recoveries obtained for all 3 methods were in the range 73-113%, with coefficients of variation between 1.1 and 11.2%. Equivalence of method performance was further demonstrated by performing replicate analyses of beef and sheep fat containing naturally incurred residues of heptachlor epoxide, dieldrin, p,p′-DDE, p,p′-DDD and p,p′-DDT. All 3 methods offer effective cleanup and acceptable recovery of organochlorine pesticides in animal fat. The sweep codistillation method has the advantages of low solvent and reagent use, simultaneous cleanup of 10 samples, and rapid turnaround, although thermal degradation of p,p′-DDT requires monitoring and control. GPC offers a high degree of automation but is a relatively slow sequential sample cleanup with high solvent use. Florisil column adsorption chromatography is a simple, proven technique but requires considerable solvent and reagent and has a low potential for automation.


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