Terbufos is an organophosphate pesticide and nematocide used in the production of bananas, sugar beets, corn and grain. It is typically applied to the seed or while planting, controlling many insects, wireworms, seedcorn maggots, white grubs, and corn rootworm larva. Terbufos is extremely toxic to workers exposed to concentrated granules. Two mixed-mode HPLC columns were used to separate terbufos with unique selectivity. Primesep 100 is a reverse-phase HPLC column that contains embedded acidic ion-pairing groups. Obelisc R retains compounds with embedded hydrophobic chains and multiple ion-pairing groups. Method can be used to retain and separate dozens of pesticides and is LC/MS compatible.