Capillary electrophoresis–mass spectrometry analysis of bisphenol A and its analogues in bottled tea beverages with dynamic pH focusing

Abstract

A simple and sensitive method for the determination of bisphenol A and its analogues at the ng/mL level in bottled tea beverages is presented. This method utilized a dynamic pH junction to focus the analyte into a more concentrated zone, based on the electrophoretic mobility difference of analytes in the sample matrix and background electrolytes in capillary electrophoresis coupled to mass spectrometry (CE-MS). The optimised analyte focusing led to enhanced signal detection with average peak heights for five bisphenols of 53–170 folds higher than conventional injections. Under optimised conditions, the method showed good linearity in the range of 0.1–100 ng/mL, excellent limits of detection (0.03–0.04 ng/mL), good analyte recovery (80.3–118.1%) with acceptable relative standard deviations (<12%). The limits of quantifications were below the maximum permissible content of bisphenol A set by the European Commission for this product. This method was used to quantitatively analyse bisphenols in six different kinds of bottled tea beverages, making it a promising tool for practical applications.