Chlorpyrifos-methyl is an organiphosphate insecticide also known and Dursban and Lorsban. It has been banned for home use since 2001 due to its toxicity, but is one of the most widely used organophosphate insecticides according to the EPA. Chlorpyrifos-methyl is on the EURL–SRM list of target pesticides in cereals and feeding stuffs. Chlorpyrifos-methyl was retained on Obelisc R, a mixed-mode HPLC column which contains ionic groups and hydrophobic chain. Method is LC/MS compatible and can be used as a general approach for analyzing chlorpyrifos-methyl and other organophosphate insecticides.