Development of a Novel Matrix Reference Material for Four Bisphenols in Fish Muscle Powder

A novel matrix reference material (RM) for accurate determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF) in fish muscle was first developed. The RM candidate was prepared by intraperitoneal administration of target compounds to tilapia, followed by muscle mincing, homogenization, freeze-drying, milling and subpacking. Homogeneity, stability and characterization studies of the RM were carried out using an optimized isotope dilution-liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) method. Sufficient homogeneity of the RM is suggested by ANOVA analysis. Short-term and long-term stability assessments, based on linear regression analysis, indicated no significant time-dependent drift for the RM stored at 60 °C for 10 days or at -20 °C for 12 months. From an interlaboratory study involving eight laboratories, the assigned indicative values of the RM were 8.71 μg/kg for BPA, 7.36 μg/kg for BPF, 10.10 μg/kg for BPS, and 5.43 μg/kg for BPAF, with corresponding expanded uncertainties (k = 2) of 0.71, 0.56, 0.80 and 0.42 μg/kg, respectively.