A multiclass, multiresidue analytical method for determining pesticide residues in air.

A multiresidue method for chlorinated, organophosphate and N-methyl carbamate insecticides has been developed for use in the National Air Monitoring Program. The method involves partitioning and extracting the pesticides from the ethylene glycol trapping solvent with methylene chloride followed by fractionation and cleanup by elution through a silica gel column. The chlorinated compounds are determined by electron capture GC, phosphate compounds by flame photometric GC, and carbamates by electron capture GC after derivatization with pentafluoropropionic anhydride. Recovery data and limits of detectability are presented for 11 chlorinated, 7 phosphate, and 7 carbamate pesticides at high and low levels. It is expected that the method will be applicable to many other compounds not successfully determined by the present analytical procedure, and that it may be adaptable for the analysis of pesticide residues in foods and other environmental samples.