Determination of bisphenol A in human breast milk by HPLC with column‐switching and fluorescence detection

Abstract

A highly sensitive HPLC method was developed for the determination of xenoestrogenic compound, bisphenol A (BPA) in human breast milk samples. After a two‐step liquid–liquid extraction, BPA was derivatized with fluorescent labeling reagent, 4‐(4,5‐diphenyl‐1 H‐imidazol‐2‐yl)benzoyl chloride (DIB‐Cl). The excess fluorescent reagent could be removed effectively using a column‐switching system. The separation of DIB‐BPA from endogenous materials in milk was carried out on two C 18 columns and fluorescence intensity was monitored at 475 nm with the excitation of 350 nm. A good linearity (r = 0.994) was observed of BPA in the concentration range of 0.2–5.0 ng mL−1 in breast milk, and the detection limit was 0.11 ng mL−1 at a signal‐to‐noise ratio of 3. Intra‐ and inter‐day precision (RSD, %) were less than 8.7 and 10.4, respectively. Twenty‐three breast milk samples of healthy lactating women were analyzed for the BPA concentration; the mean value was 0.61 ± 0.20 ng mL−1, with no correlation to the lipid content of milk samples. Copyright © 2004 John Wiley & Sons, Ltd.