Development of an analytical method based on derivatisation solid-phase microextraction combined with gas chromatography-mass spectrometry for the determination of bisphenol analogues in environmental waters

Bisphenol analogues, including bisphenol A (BPA), are pervasive environmental contaminants known for their endocrine-disrupting properties. With the increasing use of alternative bisphenols due to regulatory restrictions on BPA, monitoring their presence in aquatic systems is critical. However, their low concentrations in environmental matrices complicate their detection. This study presents the optimisation using an experimental design of a solid phase-microextraction (SPME) method, coupled with gas chromatography-mass spectrometry (GC-MS), for the determination of nine bisphenols analogues (BPA, BPAF, BPF, BPE, BPG, BPB, BPZ, BPZ, and BPC2) in drinking water, environmental waters, and wastewater samples. Acetylation was used as a derivatisation technique to improve the analytes' volatility and stability. The optimized method compromises the extraction of 15 mL of water by DVB/CAR/PDMS fibre in direction immersion mode adding 50 µL of acetic anhydride. The temperature was 100 °C and the extraction time 30 min. Method validation demonstrated excellent linearity (R² > 0.999), low detection limits in the low µg L^-¹ range, and general recoveries above 80 % in real samples. The application to 19 water samples revealed the presence of seven bisphenols analogues reaching up to 3.4 μg L^-1, with BPE detected at the highest concentrations and BPA as the most frequently detected compound. This method provides a sensitive, efficient, and environmentally sustainable approach for the analysis of bisphenols in complex water matrices, aligning with green chemistry principles.