Efficiency of Eluting Solvents for Solid-Phase Extraction During Multiresidue Analysis of 16 Pesticides in Cucumber

A study was carried out to optimize the cleanup step using a solid-phase extraction (SPE) cartridge, Florisil, for multiresidue analysis of 16 pesticides in cucumber matrix. Eluting efficiencies of two solvent systems including acetone/n-hexane and ethyl acetate/n-hexane mixtures were critically evaluated by recoveries of target anaytes from the SPE Florisil column. Based on the recovery as a measure of eluting efficiency, an acetone/n-hexane (20/80,v/v) mixture provided more than 80% recovery for 15 pesticides except bifenthrin. In case of ethyl acetate/n-hexane, 14 pesticides showed recoveries higher than 75% while those far alachlor and bifenthrin were less than 30%.