Trace level determination of bisphenol-A in wastewater and sewage sludge by high-performance liquid chromatography and UV detection

The purpose of this study was to develop and optimize a simple and economical method for the extraction and determination of bisphenol-A (BPA), using high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection at environmentally relevant concentrations in both dissolved and particulate phases. To clean-up and pre-concentrate liquid samples, solid-phase extraction (SPE) method was optimized with regard to pH, volume, washing and elution solvents for high recovery of BPA and good clean-up. For sludge samples, four extraction methods, microwave-assisted extraction (MAE), ultrasonication extraction (USE), accelerated solvent extraction (ASE) and high-pressure homogenizer (HPH), were compared for isolation of BPA from activated sludge samples. Analysis was performed by optimized procedures using HPLC-UV. Recoveries of BPA from liquid and solid phases were determined to be 90-105 and 60-90%, respectively. MAE had the highest recovery among examined extraction methods. The method detection limits were 100 ng/L and 100 ng/g dry weight. To validate the method, a mass balance study was conducted with 100 mL spiked mixed liquor volatile suspended solids (VSS) samples from three laboratory-scale porous pot reactors and concentrations of BPA in liquid and solid phases were determined using the optimized conditions. The results had an average 86% overall recovery for all samples.