Eff ect of cold plasma on degradation of organophosphorus pesticides used on some agricultural products

Th is study investigated the potential eff ect of cold plasma on reducing residues of pesticides diazinon and chlorpyrifos in apples and cucumbers and its eff ects on property of products. Two separate concentrations of each pesticide with 500 and 1,000 ppm were prepared and the samples were inoculated by dipping them into the solutions. All samples treated with pesticides were exposed to cold plasma in a monopole cold plasma apparatus (DBD) run at 10 and 13 kV voltages. Liquid-liquid extraction (LLE) was used to remove pesticide residues from the samples. Eventually, high-performance liquid chromatography (HPLC) was used to measure the amount of pesticides in the samples. Also, to investigate generated metabolites, extracts were injected into a GC/MS apparatus. In addition, the eff ects of cold plasma on humidity, tissue hardness, color and the sugar percentage of products were analyzed. Th e results revealed that treatment of samples with cold plasma considerably reduced pesticide residues without leaving any traces of harmful or toxic substances. Furthermore, it did not have any undesirable eff ects on the color and texture of the samples. Th e effi ciency of this method increased with higher voltage and longer exposure time. In general, the best results were obtained by the combination of 500 ppm concentration, 10 min exposure and 13 kV voltages. Th e residues of diazinon were reduced better than the residues of chlorpyrifos. Apples were detoxifi ed much better than cucumbers. Also, cold plasma treatment transformed diazinon and chlorpyrifos pesticides into their less toxic metabolites. Th e results showed that with increased voltage and longer exposure time, cold plasma caused few changes in moisture and glucose content, texture hardness and color of products. Th ere were no signifi cant diff erence between treated samples and control in all treatments.