Background Bisphenol compounds are non-persistent environmental endocrine disruptors and frequently detected in drinking water systems, indicating potential human health risks through drinking water.

Objective To establish and optimize a simultaneous determination method for 16 BPs in drinking water by online solid-phase extraction-ultra high-performance liquid chromatography-triple quadrupole mass spectrometry, in order to efficiently monitoring BPs in drinking water.

Methods Candidate online solid-phase extraction conditions, chromatographic columns, mobile phase systems, mass spectrometry parameters, and other conditions were compared by chromatographic peaks of BPs, and processing conditions such as water sample preservation and pretreatment were optimized. The pH level of drinking water samples was adjusted and solid particles were removed. After extraction and purification by an online solid-phase extraction system, samples were detected by ultra-high performance liquid chromatography tandem mass spectrometry and quantified by isotope internal standard method. The proposed method was verified by pure water and terminal tap water, and evaluated by spiked recovery rate and relative standard deviation. Eighty-eight tap water samples from different regions of local pipeline network were collected for method application.

Results For the 16 BPs, the calibration curves showed good linearity between 1.0 and 75 ng·L⁻¹ and the correlation coefficients were greater than 0.995. The detection limit of the method was less than 0.30 ng·L⁻¹, and the quantification limit of the method was less than 1.0 ng·L⁻¹. When the spiked concentrations for the 16 BPs were 5.0, 15, and 40 ng·L⁻¹, the average spiked recovery rates of the test substances were between (100 ± 10)%, and the relative standard deviations were all below 10%. In the method application to the local terminal water samples, the positive rates of bisphenol S (BPS), bisphenol A (BPA), and bisphenol AF (BPAF) were as high as 93.2%, 77.3%, and 29.5%, respectively. The concentrations of BPS were from not detected (N.D.) to 37.8 ng·L⁻¹, and the concentrations of BPA were from N.D. to 52.0 ng·L⁻¹.

Conclusion The method using an online solid-phase extraction system is established, featuring simple pre-treatment, small sample volume, high degree of automation, low detection limit, and good accuracy and precision. This method can be applied to the quantitative monitoring of 16 BPs at ng·L⁻¹ level in drinking water.