LAUSR

The present study reports a simple and quick sample extraction method to determine bisphenol A (BPA) and 4-nonylphenol (4-NP) in fish samples. The method is based on the complete dissolution of the analytes in a deep eutectic solvent (DES), while retaining most of the biological matrices in the pretreated solids. The pretreatment was performed for 15 min using a DES composed of choline chloride–urea (ChCl–Ur), at 1:2 molar ratio, in a closed vessel at atmospheric pressure. The target analytes were extracted with low volumes of an organic solvent, purified, concentrated, and then determined by a high-performance liquid chromatography–fluorescence detector. The average extraction efficiency of the analytes reached 95% after optimizing the critical variables. The matrix-matched calibration curves were obtained in the range of 0.07–6.50 µg g−1 for BPA and 0.30–6.50 µg g−1 4-NP with R2 greater than 0.996. Limits of detection were 0.021 and 0.015 µg g−1 for BPA and 4-NP, respectively. Limits of quantifications were below 0.1 µg g−1 for the 0.15 g sample. For both analytes, the maximum intra-day and inter-day precisions did not exceed 5.5 and 12.5%, respectively. The proposed method was applied to analyze canned tuna and fresh fish tissues. The accuracy of the method was evaluated by spiking the standard analytes to real samples, and excellent results were achieved.