Analysis of Bisphenol A in milk by using a multicommuted fluorimetric sensor

Bisphenol A (BPA) is a polyphenol widely used in industry as an intermediate in the production of polycarbonate plastics and epoxy resins, which are applied to produce plastic food containers, inner surface coating of food and beverage cans. Hence, BPA can migrate from these containers and cans with epoxy coating into foods. It is dangerous taking into account that BPA is considered as a potential endocrine disruptor, which mimics the action of the hormone estrogen. The method here proposed for the determination of BPA involves the implementation of solid-phase spectroscopy (SPS) in an automatic flow system. With this purpose, the measurement of the native fluorescence of BPA, retained on C18 silica gel together with the implementation of multicommutation have been employed for its determination in different types of milk. The analytical measurements were made at 271/305 nm (λex/λem) obtaining a detection limit (LOD) of 0.06 ng mL−1. The pre-cleaning procedure and the posterior extraction with C18 applied to the samples allowed the removal of proteins and the extraction of BPA from the matrix, respectively. The method showed an RSD lower than 6.0% (n = 10). BPA was determined in powdered milk, infant formula and pure liquid milk samples, being found in five samples at levels lower than the maximum residue limit (MRL) established by the European Union. In addition, a recovery study has been carried out where values close to 100% were observed in all cases, so demonstrating that the proposed analytical method fulfills the requirements for its application in quality control analyses.