Comparison of two thin-film microextractions for the analysis of estrogens in aqueous tea extract and environmental water samples by high performance liquid chromatography-ultraviolet detection

Two thin-film microextractions (TFME), octadecylsilane (ODS)-polyacrylonitrile (PAN)-TFME and polar enhanced phase (PEP)-PAN-TFME have been proposed for the analysis of bisphenol-A, diethylstilbestrol and 17β-estradiol in aqueous tea extract and environmental water samples followed by high performance liquid chromatography-ultraviolet detection. Both thin-films were prepared by spraying. The influencing factors including pH, extraction time, desorption solvent, desorption volume, desorption time, ion strength and reusability were investigated. Under the optimal conditions, the two TFME methods are similar in terms of the analytical performance evaluated by standard addition method. The limits of detection for three estrogens in environmental water and aqueous tea extract matrix ranged from 1.3 to 1.6 and 2.8 to 7.1 ng mL(-1) by the two TFME methods, respectively. Both approaches were applied for the analysis of analytes in real aqueous tea extract and environmental water samples, presenting satisfactory recoveries ranged from 87.3% to 109.4% for the spiked samples.