Development of Analytical Method for Determining Trace Amounts of BPA in Urine Samples and Estimation of Exposure to BPA.

We have developed a reliable analytical method for determining trace amounts of bisphenol A (BPA), a suspected endocrine disruptor, in urine samples by use of GC/MS so that daily exposure of human bodies to BPA can be estimated. We administered BPA-d16 (100μg) to volunteers in order to conduct an excretion experiment and found that the BPA was absorbed quickly through the digestive tract and excreted mainly as a glucuronide conjugate into urine, in an amount of almost 100 % in 24 hours. The results suggest that determining the BPA content of urine samples enables estimation of the exposure to BPA.The results of our analysis of urine from adults show that the average total BPA concentration was 0.82 ng/ml (0.14-5.47 ng/ml, n=91) and that the average free BPA concentration was 0.08 ng/ml (0.01-0.27 ng/ml, n=11) . Also, from a determination of whole-day urine samples, the exposure to BPA was estimated to be 1.68 μg/day (0.48-4.5 μg/day, n=22) on the average.