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  • Determination of organochlorine pesticides in ground water using solid-phase microextraction followed by dual-column gas chromatography with electron-capture detection.

Determination of organochlorine pesticides in ground water using solid-phase microextraction followed by dual-column gas chromatography with electron-capture detection.

Journal of chromatography. A (2002-08-30)
Bruce A Tomkins, Angela R Barnard
ABSTRACT

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.

MATERIALS
Product Number
Brand
Product Description

Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 24 ga, for use with manual holder
Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 24 ga, for use with autosampler
Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 23 ga, for use with autosampler