Spectrofluorimetric determination of bisphenol A in tap waters by exploiting liquid-liquid microextraction in a sequential injection system

Bisphenol A (BPA) is an emerging pollutant with estrogenic effects for humans. Relatively high concentrations (μg L− 1 range) have been found in tap waters in some countries, thus requiring fast and reliable procedures for its monitoring. In this work, a flow-based liquid-liquid microextraction procedure is proposed for preconcentration and separation of BPA, aiming at the determination based on its native fluorescence, which significantly increases in organic medium. Extraction was carried out in a sequential injection system by means of a film or the extractor formed on the tube walls (wetting film approach), followed by elution of this phase by ethanol. In this way, an enrichment factor of 15.5 was achieved with only 1.5 mL of sample and 30 μL of the extractor solvent. A linear response was observed from 5.0 to 100 μg L− 1 with a detection limit of 1.8 μg L− 1, sampling rate of 10 h− 1, and coefficient of variation of 2.3% (n = 10). The procedure was successfully applied to tap water samples and the results agreed with those obtained by the HPLC reference method.