Simultaneous determination of steroidal and phenolic endocrine disrupting chemicals in fish by ultra-high-performance liquid chromatography-mass spectrometry/mass spectrometry.

A sensitive and reliable analytical method based on pressurized liquid extraction (PLE) and ultra-high-performance liquid chromatography equipped with tandem mass spectrometry (UHPLC-MS/MS) has been developed for simultaneously determining the steroidal and phenolic endocrine disrupting chemicals (EDCs) in fish. The most effective extraction of the target EDCs is achieved by using PLE with on-line purification and the parameters have been optimized as follows: extraction solvent - methanol-acetonitrile (1:1, v/v), on-line purification material - 5 g alumina (5% water), extraction - 3 cycles, static extraction time - 5 min and extraction temperature - 60°C. Compared to the Oasis hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE), freezing-lipid filtration combined with n-hexane defatting clean-up obtains much better recoveries of the target compounds and provide cleaner extracts. The matrix effect (ME) is generally eliminated by using an internal standard method. At spiking levels of 5, 50, and 100 ng/g, the mean recoveries vary from 71.2% to 108% for the target EDCs with a relative standard deviation (RSD) less than 16%. The method limit of detection (LOD) and limit of quantitation (LOQ) are 0.04-0.08 ng/gdw and 0.07-0.27 ng/gdw, respectively. The established method has been successfully applied to fish samples from the local market to determine the target EDCs.