No abstract

Eight single and mixed polarity column packings were prepared and optimum operating parameters were determined for each column. Data were obtained for efficiency, effect on detector sensitivity, absolute retention times, and peak elution patterns. Retention and peak height response values, both relative to aldrin, are reported for 50 chlorinated pesticides and related compounds on the eight columns. The column of 3% diethylene glycol succinate and the mixed liquid phase columns of 2% OV-1/3% QF-1 and 1.5% OV-17/1.95% QF-1 performed very well by virtue of their capacity for high efficiency, response, practical retention times, and compound separation characteristics.

Pesticide residues in human adipose tissue and liver tissue samples were identified by mass spectrometry coupled with gas chromatography. An extensive extraction and cleanup procedure was adapted from existing analytical methods to separate pesticide residues from the tissue samples. Concentration of pesticides in tissue ranged from 0.073 to 28.7 ppm. Mass spectral data were computer-enhanced to identify heptachlor epoxide. Other pesticides confirmed included the /3-isomer of 1,2,3,4,5,6-hexachlorocyclohexane (HCH), several isomers and metabolites of , '-DOT, and dieldrin. Advantages, limitations, and suggested modifications for improving the combined gas chromatographymass spectrometry technique for pesticide residue analysis are discussed.

A systematic study was conducted to observe the effect on column performance of a series of 600 consecutive injections of human adipose tissue extract, both cleaned and uncleaned. Ten different column packings were used and included single and mixed nonpolar and polar liquid phases. The column characteristics observed were peak height response, efficiency, on-column conversion of p,p’-DDT to p,p’- DDD, and peak configuration. Repetitive injections of uncleaned and high lipid content human adipose tissue extract resulted in decreased performance of most columns in response, efficiency, and compound conversion. However, all columns could be maintained and restored to full or nearly full performance capacity by daily changing of the glass injection port insert used for off-column injection and the glass wool plug at column inlet.