Multiresidue analysis of pesticides in animal and fishery products by NCI mode GC/MS and dual-column GC-micro ECD]

A sensitive and quantitative multiresidue method using NCI mode GC/MS and GC-micro ECD for determining pesticides in animal and fishery products was established. The crude sample extract obtained by acetone-hexane extraction for solid samples or acetonitrile extraction for liquid samples was cleaned up with a GPC/SPE system. The first GPC pesticide fraction containing lipids and pigments was selectively collected, and loaded directly onto a graphitized carbon/PSA 2-layered column. After the second GPC pesticide fraction was collected, the 2-layered column was eluted with acetone-hexane (3: 7). The combined eluate was subjected to NCI-SIM/Scan mode GC/MS for semi-quantification. After fractionation by Florisil cartridge column SPE, each fraction was subjected to dual-column GC-micro ECD for quantification. Average recoveries (n=5) of pesticides, except for chlorothalonil and some others, from fortified samples ranged from 76.8% to 107.9% with RSD values of <9.7%.