Source
Graduate School of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan.
Abstract
A highly sensitive and selective method for simultaneous determination of some hydroxyl group-containing endocrine disruptors, including bisphenol A (BPA), bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF) and 4-nonylphenol (4-NP), was developed. The method consists of precolumn derivatization of the analytes, solid-phase extraction (SPE) and subsequent chromatographic analysis by high-performance liquid chromatography (HPLC) with fluorescence detection. 4,4'-Cyclohexylidenebisphenol (BPZ) was used as an internal standard. Derivatization was carried out using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. Parameters of the derivatization reaction (temperature, time, concentration of reagent, stability, etc.) and of the solid-phase extraction (recovery, solvent, etc.) were studied in detail. Detection limits of compounds studied in standard solutions ranged from 0.08-1.3 ppb (ng/ml). The proposed method was successfully applied to plastic samples; BPA was found in both polycarbonate and polyvinyl chloride plastics, while 4-NP was found in plastics made of polyvinyl chloride and another polymer.