Determination of 23 Endocrine Disrupting Chemicals in Environmental Water Body by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method for determination of 23 endocrine disrupting chemicals (EDCs) in environmental water body by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was proposed. The pH of water sample was adjusted to about 2.0 with 6 mol·L⁻¹ hydrochloric acid solution. 100 mL of water sample was taken into a 250 mL-separatory funnel, and 3 g of sodium chloride was added. The mixture was shaken, and 30 mL of a mixture of ethyl acetate and dichloromethane at a volume ratio of 1∶1 was added. The mixture was shaken for 5 min and settled, and the lower organic phase was dehydrated with anhydrous sodium sulfate. The solution was rotary evaporated to near dryness, and 0.2 mL of acetonitrile and 10 µL of 2.0 mg·L⁻¹ mixed internal standard solution were added. The solution was made its volume up to 1 mL with water, and passed through a 0.22 μm regenerated cellulose filter membrane. 23 EDCs in the filtrate were determined by UHPLC-MS/MS. BEN C₁₈ chromatographic column was used as the stationary phase and the mixed solution composed of 0.05% (volume fraction) aqueous ammonia solution and acetonitrile at different volume ratios was used as the mobile phase for gradient elution. Electrospray ion (ESI) source was used for mass spectrometry. The targets were detected by multiple reaction monitoring (MRM) mode in negative ion (ESI⁻) scanning mode. As shown by the results, linear relationships between the ratios of the corresponding peak area to the internal standard peak area and mass concentrations of 23 EDCs were found in definite ranges, with detection limits (3.143s) in the range of 0.60-1.75 ng·L⁻¹. Test for recovery was made by the standard addition method, giving results in the range of 72.6%-107%, with RSDs (n=6) of the determined values less than 14%. This method was used to determine 23 EDCs in actual environmental water body, and it was shown that mass concentration of bisphenol AF was the highest in surface water with 27.9 ng·L⁻¹, and 4-nonylphenol and 4-tert-octylphenol were commonly detected in sewage and wastewater, with detection amounts of 838-2 353 ng·L⁻¹ and 87.8-16 733 ng·L⁻¹, respectively.