Determination of bisphenol analogues in bottled water using deep eutectic solvent and magnetic multi-walled carbon nanotubes followed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry

Bisphenol analogues (BPs) are a class of typical environmental endocrine disruptors (EDCs) that have recently attracted increasing attention with regard to their potential effects on human health. The objective of this study was to develop a method using a magnetic soft material, which consisted of hydrophilic deep eutectic solvent (DES) and magnetic multi-walled carbon nanotubes (MMWCNTs), for the dispersive solid-phase extraction (d-SPE), coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), for the determination of the levels of nine BPs in bottled water. The hydrophilic DES enable the rapid dispersion of MMWCNTs when the material is injected rapidly into the sample solution using a pipette gun. This process can therefore be completed in a relatively short period of time, resulting in an efficient extraction. Under optimal conditions, the limit of detections (LODs) of the method were 0.0003–0.003 μg/L and the limit of quantifications (LOQs) were 0.001–0.01 μg/L. The relative standard deviations (RSDs) of the method were only 2.42–7.59 % for inter-day and 3.71–9.67 % for intra-day. The method demonstrated good reproducibilities and recoveries, rendering it suitable for the determination of BPs in large-volume water samples.