Development of a Green Water-Induced Restricted Access Supramolecular Solvent Microextraction Method for Highly Improved Determination of Pesticides with a Wide Range of Polarity in Water Samples and Cereal Flours

A novel green microextraction supramolecular (SUPRA)-based method for simultaneous preconcentration of seven pesticides, acetamiprid, azoxystrobin, bifenthrin, carbendazim, chlorpyrifos, imidacloprid, and tebuconazole, in water samples and cereal flours with further determination by HPLC-DAD was developed. The method uses 113 µL of 1-decanol as amphiphilic extractor and 500 µL of tetrahydrofuran as disperser solvent. To perform the method optimization, a 2⁵ factorial design and Doehlert design combined with Derringer–Suich desirability function and response surface methodology were used. The microextraction of the pesticides was carried out at pH 6.3 in the presence of 5% NaCl (w/v), low vortex-assisted extraction time (30 s) and it was provided high preconcentration factors (3.6–266.1), and low LOQs (8.98–29.92 µg L⁻¹). The intra-day (n = 10) and inter-day (n  = 10) precision assessed as the percentage of relative standard deviation (%RSD) for concentrations of 50.0 and 200.0 µg L⁻¹ varied from 1.7 to 4.1%. The method was successfully applied to determine pesticides in river and lake water samples using external calibration curves. Considering the property of restricted access materials of SUPRAs, the microextraction method was also applied to the direct treatment of solid samples of wheat, oat, and rice flours. High recovery values in the range of 80–112% were obtained, thereby proving the absence of possible interference from matrix components.

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