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