Hollow fiber liquid-liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection for the determination of various environmental estrogens in environmental and biological samples

A new method of hollow fiber liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for simultaneous analysis of various environmental estrogens. Taking eight environmental estrogens (17β-estradiol (E2), estrone (E1), estriol (E3), 17α-ethynylestradiol (EE), diethylstilbestrol (DES), dienestrol (DIS), bisphenol-A (BPA) and 4-t-octylphenol (OP)) as the target analytes, the factors affecting HF-LLLME-HPLC-UV were investigated in detail. Under the optimized experimental conditions, the extraction efficiency of HF-LLLME for eight target estrogens was in the range of 13.9-62.8%, and the enrichment factor was 88-376-fold. The limits of detection (LODs) of the proposed method for eight target estrogens of ES, BPA, E2, EE, E1, DES, DIS and OP were 0.11, 0.055, 0.66, 0.55, 0.51, 0.20, 0.11 and 1.46 ng/mL, respectively, which are lower than that obtained by some other sample pretreatment methods followed by HPLC-UV analysis. The relative standard deviations of the method (RSDs, cE3, BPA, DIS =5 ng/mL, cE1, E2, EE, OP = 40 ng/mL, cDES = 15 ng/mL, n = 7) are in the range of 5.5-8.4%. The developed method was applied for the determination of environmental estrogens in environmental and biological samples (sediment and fish), and none of the eight target estrogens was detected. The recoveries for the spiking samples with low, medium and high spiking levels were in the range of 73.2-117.5%. The proposed method has been demonstrated to be suitable for simultaneous determination of multiple environmental estrogens with high sensitivity, high enrichment factors, good sample clean-up ability and no derivatization required.