Simplified QuEChERS technique followed by UHPLC-MS/MS analysis for the determination bisphenol A in whole and powdered milk

Bisphenol A (BPA), an important endocrine disruptor, is employed in the manufacturing of many materials such as food packaging. The ingestion of contaminated food is considered the most relevant form of exposure to this compound. Data concerning the presence of this contaminant in milk in Brazil, however, are still lacking. In this context, an analytical method for the determination of BPA in ultrahigh temperature (UHT) milk, pasteurised milk, and milk powder was developed. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was used for sample treatment, and BPA was determined by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The method was selective for BPA in all investigated milk samples. No matrix effects were observed, thus indicating that calibration curves could be prepared in solvent for routine analysis. The method presented satisfactory accuracy, with recovery values between 78 and 94%. Relative standard deviation values obtained in the repeatability (11%) and intermediate precision (4.8%) studies were also satisfactory (HorRatr and HorRatR values less than 2). The analyte limits of detection and quantification were 0.12 and 0.36 ng/g for while milk, and 0.40 and 1.20 ng/g for reconstituted milk powder (1:10), respectively, and the sensitivity of the analytical method was considered adequate for the purpose of the present work.