Preconcentration and Simultaneous Analysis of Benzimidazole Anthelmintics in Milk Samples by Ultrasound-Assisted Surfactant-Enhanced Emulsification Microextraction and High-Performance Liquid Chromatography

The proposed ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) coupled with high-performance liquid chromatography-photodiode array detection (HPLC-PDA) has been developed for the preconcentration and simultaneous analysis of five benzimidazole anthelmintics. Dichloromethane (extraction solvent) and Triton X-114 (emulsifier) was used for extraction of the target analytes. The parameters affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, linearity was in the range from 10 to 150 μg?L^?1 with good coefficients of determination (R ²) higher than 0.994. Preconcentration factors were obtained up to 60, corresponding to limits of detection range of 1.8???3.6 μg?L^?1. Intra-day (n?=?5) and inter-day (n?=?4?×?3) precisions were obtained with relative standard deviation of retention time and peak area below 0.8 and 9.2 %, respectively. Good recoveries for the spiked target anthelmintics at different concentrations (e.g., 20, 50, and 100 μg?L^?1) of milk samples were obtained in 72.5–113.5 %. The results demonstrated that the proposed UASEME-HPLC-PDA can be used as an alternative powerful method for the simultaneous determination of the target analytes in milk samples.