Evaluation of degradation of organophosphate insecticide residues in stored corn (Zea mays L.) grains

The aims of this work were to monitor the dissipation dynamics organophosphate insecticides applied corn grains stored in supervised experiments, establish and determine minimum period post application necessary comply with established commercial standards. dichlorvos (DDVP), hlorpyrifosmethyl+deltamethrin (CPM) pirimiphos-methyl (PMM) maize grains, which then for 120 days. samples processed extracted using QuEChERS technique pesticide residues identified quantified by gas chromatography-mass spectrometry. Deltamethrin not analized. After 90 days storage, more than 80 % initial residue had been degraded, after below detection limit (LoD). DDVP, CPM PMM followed a first order degradation [Ct = C0×e(-kt)], k values 0.384, 0.025 0.020 estimated half-lives 1.8, 27.7 34.7 days, respectively. These results show that at recommended dosages, are safe use on grains; DDVP provide additional evidence further reasserting its prohibition, dates back 2018.