تحقیقات نظام سلامت (Oct 2023)
Development of Salting Out Dispersive Liquid-Liquid Microextraction for Measurement of Bisphenol A in Drinking Water and Urban Treated Wastewater Samples by High-Performance Liquid Chromatography: Optimization by the Response Surface Methodology Based on the Box-Behnken Design
Abstract
Background: Bisphenol A is known as one of the emerging micropollutants with harmful effects on human health. This pollutant enters the environment through the discharge of municipal wastewater treatment plants. In this research, the salting out dispersive liquid-liquid microextraction method was investigated for pre-concentration of bisphenol A in drinking water and urban sewage effluent samples. Due to the high enrichment factor, this method enables the measurement of small amounts of bisphenol A in the examined samples. Methods: In this method, bisphenol A forms a colored hydrophobic derivative of antipyrine with 4-aminoantipyrine in the presence of potassium hexacyanoferrate. In order to extract the resulting derivative, 250 µl of 2-phenoxyethanol was dissolved in 10 ml of the sample. Then, by adding 0.7 g of sodium chloride to the sample, fine droplets of extracting solvent were formed in the sample and the solution became cloudy. After centrifugation, the extraction phase containing bisphenol A derivative settled at the bottom of the test tube, and then, 20 µl of methanol was added in order to reduce its viscosity. The measurement was performed by a high-performance liquid chromatography at a wavelength of 480 nm. To optimize the process, the effect of the amount of 4-aminoantipyrine, potassium hexacyanoferrate, and buffer was investigated. Then, the figures of merit of the method were obtained and the performance of the method was evaluated on drinking water and urban sewage effluent samples. Findings: Under optimal conditions (2-phenoxyethanol: 250 µl, 4-aminoantipyrine 1%: 100 µl, potassium hexacyanoferrate 10%: 80 µl, buffer pH 10: 10 µl, and sodium chloride: 0.7 g per 10 ml of sample), the enrichment factor of 106, the detection limit of 0.1 ng ml-1, the limit of quantification of 0.3 ng ml-1, and the relative standard deviation (RSD) of 3.2% were obtained. Meanwhile, the correlation coefficient (CC) of the calibration curve was equal to 0.9985. Moreover, the results of the analysis of water and urban sewage effluent samples showed that the developed method had suitable performance for the measurement of bisphenol A in real matrix samples. Conclusion: Considering the low detection limit, high enrichment factor, and proper performance in real samples, this method can be introduced as a sensitive and efficient method for the measurement of very low amounts of bisphenol A in water and wastewater samples.
