Monocrotophos is a pesticide that is acutely toxic to both birds and humans. With similar action as other organophosphate pesticides it has been banned and many other countries. Monocrotophos was analyzed on two different stationary phases. Primesep 100 is a reverse phase column that contains embedded acidic ion-pairing groups, while Obelisc R retains with long hydrophobic chains and multiple ionic pairing groups on the surface. Method is LC/MS compatible and can be replicated to analyze dozens of other pesticides.