MIL-101(Cr) based d-SPE/UPLC-MS/MS for determination of neonicotinoid insecticides in beverages

Metal organic framework MIL-101(Cr) was successfully synthesized as a selective adsorbent by a facile self-assembly technique and combined with UPLC-MS/MS for enrichment and determination of neonicotinoids in fruit juices and tea beverages. Therein, MIL-101(Cr) was characterized by Fourier transform infrared spectrometry, scanning electron microscopy, X-ray diffraction, and N-2 adsorption-desorption isotherms. Box-Behnken design was applied to optimize the significant variables including the sorbent amount, pH of the matrix, eluant volume, extraction time and desorption time. The optimized conditions were sorbent amount of 20 mg, eluent volume of 1 mL, extraction time of 5 min and desorption time of 4 min. Under the optimized conditions, excellent sensitivity was achieved with the limit of detection of 0.0019-0.02 mu g/L and limit of quantification of 0.0063-0.067 mu g/L. Good linearity (R-2 >= 0.9988) was obtained within the range of 1-1000 mu g/L, and the recovery was 71.04%-101.64% with relative standard deviations (RSDs) of 1.25%-8.82% in spiked samples. The inter- and intra-day RSDs were both<8.54%. The adsorption isotherms investigated for acetamiprid, thiacloprid, and imidacloprid pesticides better fitted with the Freundich adsorption isotherm with bimolecular adsorption capacity of 71.43, 68.49, and 50.38 mg/g, respectively. These results indicate that the nanocomposite is feasible for adsorption of the target analytes at trace amounts from fruit juices and tea beverages.