The role of pesticides in the management of the destructive pest, Spodoptera littoralis, is a dominant tactic used in IPM programs .Chlorpyrifos and Cypermethrin are the most commonly used insecticides in our country. Insect resistance against such insecticides enforced cultivars to increase the recommended doses which increases the pesticide residues in our food. This study's objective was to create a new methodology to measure the residue of Chlorpyrifos and Cypermethrin in potato and tomato yields. Chlorpyrifos showed high tolerance ratio equal to 380-fold in the field strain of S. littoralis with laboratory strain, while Cypermethrin showed a tolerance ratio of 5.79-fold.

A proposed modification of QuEChERS method to ensure the effectiveness of using different sorbent nanoparticles in the purification of both Chlorpyrifos and Cypermethrin residues from co-extracts can result in falsely favorable findings in order to guarantee the security of the commercially tomato and potato yields. A new, quick and easy analytical technique was created to determine Chlorpyrifos and Cypermethrin insecticide residues Using GC-MS/MS (gas chromatography-tandem mass spectrometry). In this method, Octadecyl-modified silica (C18), graphitized carbon black (GCB) and primary secondary amine (PSA) were converted to their corresponding nanoparticles, C18-NPs, GCB-NPs and PSA-NPs for the first time, and used in the sample purification step.

Acetonitrile was used to extract the samples and measured using internal standards and matrix-matched calibration. With values of r2>0.99, all pesticides demonstrated good linearity in their respective ranges. With RSDs of 0.2 percent -14.4 percent, the average recoveries of the pesticide-spiked samples varied from 70.0 percent to -112.2 percent. The modified QuEChERS approach proved that PSA-NPs could be recommended for the extraction of both Cypermethrin and Chlorpyrifos from tomatoes. While C18-NPs is recommended for reducing unusual matrix suppression effect of Cypermethrin from potatoes.