A new pretreatment and improved method for determination of selected estrogens in high matrix solid sewage samples by liquid chromatography mass spectrometry

• Published in: Microchemical journal 2012-09, Vol.104, p.49-55
• Main Authors: Chen, Qingcai, Shi, Jianghong, Wu, Wei, Liu, Xiaowei, Zhang, Hui
• Format: Article
• Language: English
• Subjects: Aqueous alkali extraction; Estrogen; LC–MS/MS; Matrix effect; Optimization of pretreatment method; Solid samples
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2012.04.008

This article describes a pretreatment procedure for samples that possess high matrix interferences to better analyze four estrogens including estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinyl estradiol (EE2) and xenoestrogens bisphenol A (BPA) in solid samples, including the activated sludge and sediment samples investigated here. During the pretreatment procedure, the target compounds were extracted from the samples using accelerated solvent extraction (ASE), and the extracted samples were then purified using four steps for clean-up: liquid–liquid extraction (LLE), Florisil clean-up, aqueous alkali extraction (AAE) and hydrophilic–lipophilic balance (HLB) enrichment. The absolute recoveries of the activated sludge and sediment were 88–97% and 75–100%, respectively, and the limits of detection were both below 0.1ngg−1. After the activated sludge and sediment samples were purified using the four clean-up steps, their matrix interference effects decreased to 0.5–32% and −3.2–0.8%, respectively, and their absorbance values were also clearly reduced. However, the activated sludge and sediment samples that were extracted by ASE but were not purified through the above-mentioned four steps resulted in matrix interference effects on the four estrogens and BPA that reached 81–233% and 47–95%, respectively, in which E3 and BPA were completely suppressed in the activated sludge samples. ► This analytical method is applied for trace estrogens under a complex matrix. ► Good purification results are ensured by a precisely designed procedure. ► The purification effects were evaluated by UV–vis and matrix effect equation. ► Both recovery and optimization experiments were conducted for each procedure. ► Factors which influence the recovery were discussed in a mechanism level.