Innovative dispersing material based on silica gel and deep eutectic solvents for the extraction of pesticides from hazelnuts followed by UHPLC-MS/MS analysis

In this work, a matrix solid-phase dispersion extraction (MSPD) followed by a back-extraction method was used to determine 11 pesticides from hazelnut samples. An innovative dispersing material was prepared and a silica gel bulk was impregnated with a choline chloride:oxalic acid (molar ratio 1:1) deep eutectic solvent (DES). The material was characterized via Fourier transform infrared spectroscopy, laser diffraction analysis, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Through a preliminary one-factor-at-a-time study and a final Box-Behnken Design optimization, the sample-to-dispersing material ratio, grinding time, and extraction solvent volume parameters were optimized, yielding the following values: 1:3.8 (w/w), 1.9 min, and 2.4 mL, respectively. Ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis was used. The method was validated according to SANTE 11,312/2021 guidelines. Recoveries were evaluated at three different spike levels (LOQ, 10LOQ, and MRL) and were all above 50 %. Precision and trueness intra- and interday were all below 20 %. Linearity was studied in the range of interest (LOQ-100 µg kg^-1) with determination coefficients greater than 0.991. The limits of detection and quantification were in the range of 0.03-0.5 µg kg^-1 and 0.1-1.7 µg kg^-1, respectively. The sustainability of the method was evaluated using AGREEprep, BAGI and ComplexMoGAPI software.