Analysis of Organophosphorous Pesticides in Produce using Acetonitrile Extraction, Dual-Layer Carbon-Aminopropylsilica Cleanup and GC-NPD Detection

GC analysis coupled with Nitrogen-Phosphorous detection could selectively detect organophosphorous pesticides with low background in comparison to MS detection.

The clean-up protocol using acetonitrile/MgSO₄ extraction and dual layer carbon/PSA SPE cleanup resulted in acceptable recoveries for a majority of the pesticides studied. The recoveries were improved by optimizing the toluene content of the SPE elution solvent to 35% toluene-65% acetone.

The recovery of organophosphorous pesticides was found to be matrix- dependent; in onion and cabbage samples the recoveries were lower than in apple and button mushroom samples.