Bisphenol A-glucuronide measurement in urine samples

Bisphenol A (BPA), is one of the most abundant endocrine disruptors that are present in our environment, and has been repeatedly detected in most human biological samples. As it has been suggested that part of the BPA measured in human samples is due to contamination during samples collection or laboratory measurements, we have developed a specific radioimmunoassay for the measurement of BPA-glucuronide (BPA-G), the main endogenous metabolite of BPA in urine. We used a polyclonal anti-BPA antibody which has a 95% cross reactivity with BPA-G, and insignificant cross reactivity with most analogous BPA phenolic structures. To eliminate unconjugated BPA from urine samples, an extraction step with dichloromethane was required. The method proved to be valid, precise and accurate in the range of 0.05 μg/L to 5 μg/L. With this method, we measured BPA-G in 163 urine samples from a hospital population. We detected BPA-G in all samples, with mean values of 4.64 μg/L. In conclusion, the present radioimmunoassay is a useful tool for the screening of BPA exposure in human populations encompassing the problem of eventual contamination from laboratory manipulation.