Research Product

Quantitative recovery of some organophosphorous pesticide residues has not been possible with existing silica gel-cleanup procedures. We have developed a modification that permits quantitative recovery of all organophosphorous pesticides tested, except those with a carbamate functional group. The method uses a 3.5 g silica gel column with a 1% acetic acid wash to condition the column prior to the addition of the sample. Percentage recovery and standard deviation of compounds such as phorate and disulfoton are 96 (5.6) and 98 (1.0), respectively. Recoveries range from 92 to 101% for the 11 compounds tested.