The Use of Solid Phase Extraction for Pesticide Residue Analysis of Crops

An Alternative to Liquid-Liquid Partitioning

Abstract

Solid-phase extraction with bonded silica sorbents has been developed as an alternative to liquid-liquid partitioning cleanup in the pesticide residue analysis of crops. Elution patterns and recovery from an octadecyl (C18) sorbent were determined for 17 organophosphorus, nine carbamates and three other pesticides with the sample matrix from rice grain. The recovery was good for all compounds whose properties were water-soluble at below 25, 000mg/l. The sample loading test proved that a cartridge containing only 0.5g of sorbent mass was capable of trace enrichment of analytes with a sample matrix from 20g of grain. Among various types of bonded silica sorbents, octyl (C8), ethyl (C2) and cyclohexyl (CH) sorbents were superior to others in retention and selective elution. The new technique was compared with the conventional method which requires liquid-liquid partitioning. The availability of the technique was also evaluated in several fruits and vegetables.