Dispersive micro solid-phase extraction with gas chromatography for determination of Diazinon and Ethion residues in biological, vegetables and cereal grain samples, employing D-optimal mixture design

In the present study, a dispersive solid-phase microextraction/gas chromatography-flame ionization detection was developed for extraction and simultaneous measurement of two organophosphorus pesticides (Diazinon and Ethion) residues in rice, cucumber, tomato, and mice liver samples. For this purpose, magnetic NH2-MIL-53(Al)@ Chitosan was synthesized and with coating magnetic Fe3O4 nanoparticles and with NH2-MIL-53(Al) in the presence of Chitosan to prepare an effective and magnetic sorbent for the extraction of Diazinon and Ethion. The value of sorbent components was optimized with a D-optimal mixture design. The optimum percentages of the sorbent components, including magnetic Fe3O4 nanoparticle, NH2-MIL-53(Al), and Chitosan, were 21, 45, and 33%, respectively. Magnetic NH2-MIL-53(Al)@ Chitosan nanocomposites were characterized by FTIR, SEM, and VSM techniques. The effects of various parameters on the extraction efficiency of Diazinon and Ethion, including pH, type and volume of desorption solvent, dispersion time, sorbent amount, extraction time, sample solution volume, and desorption time, were studied and optimized by using the design of the experiment. The calibration curves were linear in the range of 0.23-220 and 0.13-200 mu g L-1 for the determination of Diazinon and Ethion, respectively. Besides, LODs of 0.07 and 0.04 mu g L-1 were obtained for the measurement of Diazinon and Ethion, respectively. Intra-day and inter-day RSDs were lower than 4.12 and 5.59% for the determinations of the analytes (n = 5) with a concentration of 10.0 mu g L-1 under the optimum conditions, respectively. The proposed procedure was effectively applied to determine the Diazinon and Ethion residues in the rice, cucumber, tomato, and mice liver samples with a proper recovery in the range of 91.25-104.35 % and a low RSD (<= 6.45%).

Automated summary

A new method was developed for the extraction and simultaneous measurement of two organophosphorus pesticides residues in rice, cucumber, tomato, and mice liver samples. The magnetic NH2-MIL-53(Al)@ Chitosan sorbent prepared in this study showed high extraction efficiency and precision under optimized conditions.