Simultaneous Determination of Seven Bisphenol Analogues in Surface Water by Solid-Phase Extraction and Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

For the simultaneous measurement of seven types of bisphenol analogues (BPs) in surface water, a method combining solid-phase extraction (SPE) with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed. The extraction efficiency was improved by optimizing the parameters that affect it, including the solid phase extraction cartridge, pH, enrichment factor, flow rate, rinsing and elution volumes. On the basis of a single factor experiment, an attempt to obtain the result of optimizing by response surface method was made, and the optimal parameters were as follows: at a flow rate of 8 mL/min, 1000 mL of water sample was run through the hydrophilic-lipophilic balancing cartridge, rinsed with 10% methanol, eluted with 9 mL methanol, and concentrated with nitrogen using an automatic solid-phase extraction system. The analytes were separated on an Acquity UPLC BEH C18 column using gradient elution with a mobile phase of acetonitrile and 0.05% (v/v) ammonia, and then analyzed using UPLC-MS/MS using multiple reaction monitoring in the negative-ion mode, with an 8-minute chromatographic run time. In the range of 1-500 μg/L, seven BPs showed good linearity with correlations greater than 0.99. The recovery ranged from 82.3%-96.7%, and the range of matrix effect was 89.2% to 107%. These results indicated excellent recovery and minimal matrix effect. The limits of detection were 0.025-1.5 ng/L, the relative standard deviation ranged were 2.9%-8.5%. Using the developed method, five BPs were detected in Luoma Lake and four BPs were detected in inflow rivers. BPA and BPF were the predominant BPs, and the concentration of BPA was the highest. The method was proved to be sensitive, accurate and efficient, and it was suitable for qualitative and quantitative analysis of seven BPs in surface water.