Contamination of ultrapure water with bisphenol A leached from polysulfone ultrafilter

► We identified the source of bisphenol A (BPA) contaminants in ultrapure water. ► We determined total amount of BPA extractables in polysulfone (PS) ultrafilter. ► We obtained elution profile of BPA released from PS-based ultrafilter. ► Only 2% of total extractable BPA was released during dispensation of 33.5-L water. Ultrapure water produced by a water purification system is one of the most essential and widely used reagents in laboratories. However, its quality is usually the least well-characterized and often overlooked. Here we investigate the contamination of ultrapure water by bisphenol A (BPA) leached from a polysulfone (PS) ultrafilter in a water purification system. To evaluate the level of BPA in ultrapure water, we used an offline solid-phase extraction (SPE) coupled with liquid chromatography mass spectrometry (LC–MS). Initial BPA level leached from a new PS ultrafilter was 0.70±0.06ng/mL. The concentration of BPA decreased gradually with continuous dispensation of purified water and was 0.20±0.02ng/mL at 33.5-L dispensation. The total amount of extractable BPA was 64.4±1.4μg per PS ultrafilter. The cumulative amount of BPA leached during dispensation of 33.5-L water was 1.2±0.1μg, which only accounts for 2% of the total amount of extractable BPA.