Head Space Gas Procedure for Screening Food Samples for Dithiocarbamate Pesticide Residues

Abstract

Abstract screening procedure has been developed for dithiocarbamate residues in foods. The CS2 evolved from an H2SO4-sample mixture at 60°C for 30 min was determined by GLC; recoveries of ferbam, thiram, and ziram added to apples, strawberries, lettuce, celery, cabbage, cucumber, and carrots ranged from 80 to 114% at 3.5 ppm and from 86 to 112% at 7 ppm. Recoveries of maneb, nabam, and zineb were not satisfactory. When an HCl-stannous chloride reagent was substituted for the H2SO4 reagent, recoveries of the ethylenebisdithiocarbamates were considerably improved. Maneb and ziram recoveries ranged from 70 to 95% in all samples; ferbam, thiram, and ziram, from 84 to 100%; and nabam, from 44 to 83%. The difference between duplicate recovery values, using the latter reagent, ranged from 0 to 11.2% units; 87% of these values were less than 10%.