Green spectrophotometric approaches for simultaneous analysis of tomato pesticides in commercial formulations and environmental samples

Abstract

Tomatoes are in the top ten fruits and vegetables for containing levels of pesticide residues. In this study, three green accurate simple spectrophotometric methods were introduced for estimation of the collectively sprayed tomato pesticides, hexythiazox (HX), imidacloprid (IM), and thiamethoxam (TH). The first method depends on measuring the amplitude values at 248, 207 and 228 nm for HX, IM and TH, respectively after obtaining their mean centered ratio spectra. The second one is based on subtracting two amplitude values on ratio spectra of the pesticides mixture, which cancel out the interference of two of them and allows the determination of the third one. The two subtracted amplitude values were 204.8–215.6, 215.6–217.6, and 217.2–228.4 nm, for HX, IM and TH, respectively. The last method uses three successive derivatization steps on the ratio spectra after which HX, IM and TH can be determined at 211.4, 205.4, and 230.8 nm, respectively. The introduced methods were validated according to international conference on harmonization (ICH) recommendations and were proven to be suitable for the assay of HX, IM, and TH in commercial formulations, and field tomato samples using very simple extraction steps. The eco-friendliness of the developed methods was assessed using the Eco-scale analytical tool. The obtained score adds on the minimum environmental hazards to the several advantages of our proposed methods.