Simultaneous Determination of Six Estrogens in Water for Aquaculture with Microwave Assisted Derivatization by GC/MS

An endocrine disrupter is defined as “an exogenous substance that causes adverse health effects in an intact organism, or its progeny, consequent to changes in endocrine function”. In the past few years, many papers have highlighted the potentially dangerous consequences to human and wildlife of the presence of endocrine disrupting compounds in aquatic environment. As those compounds have high physiological activity for human and animals at very low concentration, and can be accumulated, assimilated and biomagnified in the tropic web. Thus, the pollution and effect of endocrine disrupters, such as estrogen in aquatic environment should be closely concerned. A method was developed for simultaneous determination of six estrogens (estriol,17-β-estradiol, estrone, diethylstibestrol, mestranol, ethinylestradiol) in water for aquaculture by microwave assisted derivatization and gas chromatography-mass spectrometry (GC/MS). The six estrogens were enriched and purified by C18 solid phase extraction column, and then were derived with microwave, using N-methyl-N-(trimethylsilyl) trifluoro acetamide (MSTFA) as derivatization reagent and ethylene acetate as reaction solvent, then the derivatives were analyzed by GC/MS. The quantification was achieved with estradiol-D₂ and diethylstilbestrol-D₈ as the internal standards. Good linear relationships were obtained in the range of 1-500 μg/L for estrogens with the correlation coefficients (R²) not less than 0.999 3, the limits of detection (LOD, S/N≥3) were 0.4-2 ng/L. The recoveries were 88.5%-106% at the three spiked levels. and the relative standard deviations (RSD) were 0.29%-11.9%, which were below 15%. The method shows high sensitivity, good precision, simple and high analytical speed. It could be applied to the simultaneous detection of the six estrogens in water for aquaculture, and which maked up for the shortcomings of cumbersome and time-consuming for traditional GC/MS method. Furthermore, the derivatization in this method was used microwave oven, which made the procedure more cheaper and easier uses.