Analysis for organophosphorus insecticides and metabolites

Extraction and cleanup methods used for the analysis of organophosphate pesticides are similar to those used for chlorinated hydrocarbons but differ in some important details. Many organophosphates are lost during extraction of acetonitrile solutions containing organophosphates with petroleum ether; dichloromethane is substituted. Also, cleanup by column chromatography on mixed adsorbents containing charcoal results in better recoveries than can be obtained on Florisil alone. The detectors used for measurement of organophosphates by GLC are almost unique for this group of compounds. TLC is very useful for confirming the identities of the compounds, and several promising optical methods are available for their measurement. Methods for the analysis of metabolites of this group are basically similar, since all organophosphates undergo dealkylation reactions and cleavage of the acid anhydride bond. However, measurement of the polar group which is removed during phosphorylation or other reactions involving cleavage of the acid anhydride bond is a problem unique for each compound.