Determination of Feminizing Chemicals in Water using Ultra-Performance Liquid Chromatography/Tandem Mass Spectrometry: Method Development and Applications
Date Issued
2009
Date
2009
Author(s)
Lien, Guang-Wen
Abstract
Estrogenic endocrine-disrupting chemicals (EDCs) are widely distributed over the aquatic environment and may interfere with reproductive functions of aquatic creatures even at trace levels. EDCs may also disturb the endocrine system of human beings if they exist in drinking water. Currently little is known about the levels and removal of these bioactive substances in each step of drinking water treatment. One of the major obstacles to the relating studies is how to detect trace amount of EDCs in complex environmental matrixes. This study aimed at employing ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) coupled with chemical derivatization and decreasing the matrix effects from real samples through chromatographic technique to improve the detection sensitivity of EDCs in water.erivatization of phenolic EDCs using dansyl chloride and pentafluorobenzyl bromide (PFBBr) can enhance the ionization efficiency and improve the sensitivity on MS. Consequently, this study compared the sensitivities and matrix effects of four ionization methods combined with four liquid chromatographic systems on estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), 4-nonylphenol (NP), 4-tert-octylphenol (OP), bisphenol A (BPA) and their derivatives of dansyl chloride or PFBBr. The four ion sources were electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), atmospheric pressure photoionization (APPI) and APCI/APPI, respectively; the four liquid chromatography (LC) systems were UPLC method with and without post-column split (5:1), a mixed mode column and two-dimensional LC (2D-LC) method. his study evaluated the matrix effects and the performance of ionization methods using raw water with post-extraction spike. The analysis was carried out using a Waters Acquity UPLC coupled with a Waters Quattro Premier XE triple-quadrupole mass spectrometer. The results showed no significant differences in matrix effects among native analytes using ESI, dansylated analytes using each ion source except for APPI, and PFBBr derivatives using APCI for the above four LC methods. ansylated compounds produced the most intense signals using ESI and then APPI, which were both up to three orders of magnitude than that without derivatization. PFBBr derivatization increased the signal intensity of analytes up to one order of magnitude than those of underivatized ones. The signal intensity of dansylated compounds was higher than those of PFBBr derivatives. The response of analytes using APCI/APPI mode was similar to that at APCI mode; the dual-source ionization did not improve the signals.ansylated compounds using ESI under UPLC system yielded the strongest signals and were less susceptible to matrix effect; consequently, this combination was further evaluated and validated by sewage treatment plant effluents and river water. The on-column detection limit of dansylated compounds (E1, E2, E3 and EE2) using selected ion monitoring (SIM) and selected reaction monitoring (SRM) modes, defined as a signal-to-noise ratio of three, ranged from 0.44 to 1.5 pg and from 0.05 to 0.20 pg, respectively. The limits of detection (LODs) with SRM in sewage treatment plant effluents and river water were 0.23-0.52 and 0.56-0.91 ng/L, respectively.sing the developed method, the study surveyed the levels of these EDCs in different treatment steps of five representative drinking water treatment plants. The LODs of steroid estrogens in raw water with SIM and SRM were 0.20-0.68 ng/L and 0.04-015 ng/L, respectively. The four steroid estrogens in raw water and finished water ranged from < LOD to 5.5 ng/L and < LOD to 1.17 ng/L, respectively. NP survived in each treatment step and the concentrations ranged from 25 to 378 ng/L, and its levels in finished water were all below 83 ng/L. The levels of OP and BPA in most samples were close to the backgrounds in lab blanks. The levels of the steroid estrogens in raw water were similar among the five plants even though their locations and water sources are different. Most of the estrogenic chemicals can be removed effectively through drinking water treatment steps except for NP, and there were no differences in the removal efficiency between conventional steps only and those with additional advanced procedures. n conclusion, this study developed and validated a qualitative and quantitative method on detecting EDCs with dansyl chloride derivatization by UPLC/MS and UPLC/MS/MS. The new method provided a fast chromatographic separation (< 5 min) and the LODs of the EDCs in environmental waters using SIM reached low-ng/L, and the quantitative results were comparable with those of SRM. In addition, levels of the analytes were not significantly different in the finished water between conventional and advanced treatment processes; the four estrogens at levels of few ng/L cannot be further reduced after the treatment of activated carbon adsorption or reverse osmosis process. It is still essential to prevent water sources from contaminations of EDCs.
Subjects
chemical derivatization
dansyl chloride
pentafluorobenzyl bromide
drinking water treatment
endocrine-disrupting chemicals
Type
thesis
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