Simultaneous determination of carbaryl, malathion, fenitrothion, and diazinon residues in sesame seeds (Sesamum indicum L.)

A method is described for the simultaneous determination of carbaryl (1-naphthyl methylcarbamate), malathion [diethyl (dimethoxythiophosphorylthio) succinate], fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), and diazinon (O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate) in sesame (Sesamum indicum L.) seeds. Sesame seeds were:Soxhlet extracted with n-hexane, and the extract was subjected to a liquid-liquid partitioning and column cleanup to remove the oily coextractives prior to analysis by high performance liquid chromatography (HPLC). The mean percent recoveries (+/- standard deviations) from sesame-seeds fortified-with carbaryl (0.004 to 0.035 mug/g), malathion (0.53 to 4.25 mug/g), fenitrothion (0.22 to 1.78 mug/g), and diazinon (0.54 to 4.35 mug/g) were 83.3 +/- 5.7, 85.5 +/- 6.6, 85.6 +/- 7.2, and 88.4 +/- 4.8 respectively. The method was used for the simultaneous analysis of carbaryl, malathion, fenitrothion, and: diazinon residues in sesame seeds obtained from an Ethiopian field crop that had been treated with the pesticides during its growing period.