An eco-friendly sample preparation procedure base on low-density solvent-based air-assisted liquid-liquid microextraction for the simultaneous determination of 21 potential endocrine disruptors in urine samples by liquid chromatography-tandem mass spectrometry

A simple and rapid procedure for simultaneous determination of 21 potential endocrine-disrupting chemicals (EDs) in urine samples by liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed. The novelty of the present procedure is based on the use of low-density solvent air-assisted liquid-liquid microextraction (LDS–AALLME) as a sample preparation step. The target analytes were 7 bisphenols, 7 parabens, 5 benzophenones, and two antimicrobials. The parameters (type and volume of solvent, extraction time (cycles), sample pH, ionic strength, and agitation) that influence the extraction efficiency in the LDS–AALLME were investigated and optimized. Under the optimized conditions, the matrix-matched calibration curves of all analytes presented correlation coefficients higher than 0.99 (range level of 1–20 ng mL−1). Very low LODs and LOQs ranging in 0.0003–0.15 ng mL−1 and 0.001–0.2 ng mL−1, respectively, were obtained. Recoveries from spiked samples at two concentrations (2.50 ng mL−1 and 15 ng mL−1) ranged from 91% to 120% while the precision (%, RSD) was lower than 15% for all studied compounds. The proposed combination of LDS–AALLME with LC–MS/MS is an environmentally friendly, sensitive and simple analytical alternative for the determination of EDs in urine samples without the use of any special apparatus for sample preparation, which is particularly suitable for human biomonitoring studies where many samples should be processed in less time. Finally, the proposed procedure was successfully applied to the determination of the analytes in 20 urine samples from Brazilians adults.