Measurement of bisphenol A in human urine using liquid chromatography with multi-channel coulometric electrochemical detection

Environmental exposure levels of bisphenol A (BPA) in human were investigated by measuring BPA glucuronide (BPA-G) in urine. After enzymatic hydrolysis of glucuronide substances in urine, BPA was extracted with diethyl ether. The extract was analyzed using a column-switching HPLC system employing a C8 and a C18 column with multi-channel coulometric electrochemical detection (ECD). The sensitivity and selectivity provided with redox mode of ECD allowed measurement of low level BPA in hydrolyzed urine. The quantification limit of BPA-G in urine was 0.2 ng/ml. RSDs of the intraassay precision were less than 3% and recoveries of the method were over 96% when analyzing BPA spiked urine samples (1.0 and 10 ng/ml). In a group of 48 women students, the level of BPA-G in urine ranged from 0.2 to 19.1 ng/ml with a median concentration of 1.2 ng/ml. Normalized against urinary creatinine, BPA-G ranged from 0.1 to 11.9 ng/mg creatinine with a median of 0.77 ng/mg creatinine.