[Analysis of organochlorine pesticides and pyrethroid pesticides in vegetables by gas chromatography-electron capture detection coupled with solid-phase extraction using multiwalled carbon nanotubes as adsorbent].

A multi-residue analytical method based on solid-phase extraction(SPE) with multi-walled carbon nanotubes(MWCNTs) as adsorbent was developed.The determination of 6 organochlorine pesticides and 7 pyrethroid pesticides in vegetables(including cucumber,cherry tomato,cabbage,lettuce,purple cabbage,leek,shallot and onion) was carried out by gas chromatography-electron capture detection(GC-ECD).The GC-ECD method used two columns(HP-50 and HP-1) and two ECD detectors.The HP-50 column was used for the analysis and the HP-1 column for validation.The clean-up conditions were optimized.The analytes were extracted by acetonitrile,and the extract was cleaned up by the MWCNTs SPE cartridge.The extract was re-dissolved by hexane,eluted with acetone-hexane(7∶3,v/v) from the columns.The recoveries were over 70% for the 11 pesticides in the 13 pesticides.The results indicated that the MWCNTs SPE cartridge was efficient for 8 vegetable samples,because it reduced the contamination of the coloring materials to GC-ECD.The experimental results showed the MWCNTs SPE cartridge can adsorb the coloring materials and the eluant was nearly colorless.