Acephate,methamidophos and monocrotophos residues in a laboratory‐scale oil refining process

Acephate, methamidophos and monocrotophos are insecticides used in oil palm plantations for the control of bagworms and leaf‐eating caterpillars. The main purpose of this study was to determine whether the physical refining process at laboratory scale, which simulated the manufacturing process, could remove the residues of these three insecticides in crude palm oil, in the unlikely event that crude palm oil were contaminated with these organophosphorus insecticides. A series of crude palm oil samples spiked with low (0.1 µg/g) and high (1.0 µg/g) levels of these insecticides were subjected to a laboratory‐scale physical oil refining process. Oil samples drawn at various stages of the refining process, namely, degumming, bleaching and deodorization, were analyzed using an in‐house analytical method. The results obtained from these experiments suggest that the physical refining process is capable of effectively removing residual insecticides from crude palm oil. The final product of crude palm oil refining, the refined, bleached and deodorized palm oil, was found to have no detectable levels of acephate, methamidophos and monocrotophos.