Sensitive Determination of Bisphenol A In Urine Using Automated Solid-Phase Extraction Followed by LC-MS/MS Analysis: Application to a Human Biomonitoring Study in Brazil

Bisphenol A (BPA), an endocrine disruptor present mostly in polycarbonate plastics and epoxy resins, can migrate into food and beverages, resulting in human exposure. This study aimed to develop and validate an improved liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method for measuring BPA levels in urine, applying this method for BPA exposure evaluation in a Brazilian cohort, along with BPA hair levels. Samples from 100 volunteers were collected. Urine samples were extracted using an automated solid-phase extraction procedure. The assay had a 6.5-min run time, a linear range of 0.10-25 ng mL-1, precision of 3.8-18.1%, and accuracy of 96.6-103.4%. BPA was detected in all tested urine samples (median 0.86 ng mL-1). In hair, 47% of samples had detectable BPA concentrations (median 4.8 ng g-1). No correlation was found between BPA levels in urine and hair. All levels were below the safety threshold, indicating minimal risk for the studied population, with higher urinary BPA linked to canned product consumption and higher hair levels to a healthier diet.