Reliable quantification of bisphenol A and its chlorinated derivatives in human breast milk using UPLC-MS/MS method

Bisphenol A is a widespread industrial chemical which over the past decade has demonstrated its toxicity as an endocrine disruptor. Chlorine present in drinking water may react with bisphenol A to form chlorinated derivatives, which have demonstrated a heightened level of estrogenic activity. In this work, we have comprehensively validated a method using on-line SPE-UPLC-MS/MS and isotope dilution quantification to measure bisphenol A and its chlorinated derivatives in human breast milk according to accepted guidelines. Deutered bisphenol A was used as internal standard. The matrix calibration curve ranged from 0.40 to 6.40 ng/mL for each of the target compounds and provided good linearity (r²>0.99).This method was precise (the intra and inter-day coefficient of variation was <20% at two different concentrations (0.40 and 3.20 ng/mL) and accurate (recovery ranged from 81% to 119%). The limits of detection obtained for BPA and its chlorinated derivatives ranged from 0.01 to 0.09 ng/mL. The limit of quantification for all the compounds validated at 0.40 ng/mL when using 500 μL of milk was found to be suitable for the concentration existing in real samples. The analytical method developed in this study is in accordance with the requirements applicable to biomonitoring of BPA and its chlorinated derivatives in human breast milk.