Determination of organochlorine pesticides in ground water using solid-phase microextraction followed by dual-column gas chromatography with electron-capture detection.
A rapid, sensitive, convenient, and highly quality-assured method is presented for the determination of 19 organochlorine pesticides (OCPs) in small samples (10 ml) of ground water. Samples are initially fortified with 2,4,5,6-tetrachloro-m-xylene (surrogate) and decachlorobiphenyl (retention time marker), then extracted with a 30-micron thickness polydimethylsiloxane solid-phase microextraction fiber. The analytes collected are thermally desorbed in a heated gas chromatographic inlet, separated using independent fused-silica capillary columns ("primary" and "confirmatory"), and detected using electron-capture detection. Two independent statistical procedures were used to evaluate the detection limits, which typically range between 10 and 40 ng l-1, for these analytes. Method performance was also evaluated using two additional protocols employing "performance evaluation" samples, in which authentic ground water samples were fortified to ca. 100 ng l-1 in each of at least six OCPs. The method satisfies additional strict criteria based on uniformity of fiber performance and minimal degradation of the thermally-sensitive analytes endrin and DDT.
Environmental Chemistry and Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6120, USA. tomkinsba@ornl.gov
Bruce A
BA
Tomkins
Angela R
AR
Barnard
D002138:Calibration; D002849:Chromatography, Gas / Q000379:methods*; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides / Q000032:analysis*; D011786:Quality Control; D012015:Reference Standards; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D014874:Water Pollutants, Chemical