Application note: BPA in beverages by SALLE extraction and LC-MS/MS

Automated Salting-out Assisted Liquid-Liquid Extraction (SALLE) and determination of bisphenol A in beverages using a robotic autosampler and LC-MS/MS

Salting-out Liquid-Liquid Extraction (SALLE) of beverages enables the use of more polar organic solvents for that can be injected directly to the LC-MS/MS system for analysis. Due to the salting out effect, even water miscible solvents, such as acetonitrile, form a two-phase or bilayer system after extraction eliminating the need for evaporation and solvent exchange prior to LC-MS/MS. In this study, the SALLE method was automated by the GERSTEL MultiPurpose Sampler MPS roboticPRO, extracting bisphenol A (BPA) from a variety of beverage samples combined with direct introduction of the prepared extract to the LC-MS/MS system. After pipetting the sample into a vial, adding d16-BPA internal standard, and crimping the vial, the rest was performed automatically by the MPS. This included adding liquids, agitating, centrifugation, transferring the supernatant, and injection to the analysis system. The beverages analysed include Soda (diet and regular), orange juice (with and without pulp), iced tea, iced coffee with cream, and a vitamin fortified protein drink. Very good recovery, linearity, and precision were obtained for BPA in the listed beverages.