An isotope-dilution standard GC/MS/MS method for steroid hormones in water

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An isotope-dilution quantification method was developed for 20 natural and synthetic steroid hormones and additional compounds in filtered and unfiltered water. Deuterium- or carbon-13-labeled isotope-dilution standards (IDSs) are added to the water sample, which is passed through an octadecylsilyl solid-phase extraction (SPE) disk. Following extract cleanup using Florisil SPE, method compounds are converted to trimethylsilyl derivatives and analyzed by gas chromatography with tandem mass spectrometry. Validation matrices included reagent water, wastewater-affected surface water, and primary (no biological treatment) and secondary wastewater effluent. Overall method recovery for all analytes in these matrices averaged 100%; with overall relative standard deviation of 28%. Mean recoveries of the 20 individual analytes for spiked reagent-water samples prepared along with field samples analyzed in 2009–2010 ranged from 84–104%, with relative standard deviations of 6–36%. Detection levels estimated using ASTM International’s D6091–07 procedure range from 0.4 to 4 ng/L for 17 analytes. Higher censoring levels of 100 ng/L for bisphenol A and 200 ng/L for cholesterol and 3-beta-coprostanol are used to prevent bias and false positives associated with the presence of these analytes in blanks. Absolute method recoveries of the IDSs provide sample-specific performance information and guide data reporting. Careful selection of labeled compounds for use as IDSs is important because both inexact IDS-analyte matches and deuterium label loss affect an IDS’s ability to emulate analyte performance. Six IDS compounds initially tested and applied in this method exhibited deuterium loss and are not used in the final method.
Publication type Book chapter
Publication Subtype Book Chapter
Title An isotope-dilution standard GC/MS/MS method for steroid hormones in water
DOI 10.1021/bk-2013-1126.ch004
Volume 1126
Year Published 2013
Language English
Publisher ACS Publications
Publisher location Washington, D.C.
Contributing office(s) Branch of Analytical Serv (National Water Quality Laboratory), National Water Quality Laboratory, Toxic Substances Hydrology Program
Description 80 p.
Larger Work Type Book
Larger Work Subtype Other Government Series
Larger Work Title Evaluating Veterinary Pharmaceutical Behavior in the Environment: ACS Symposium Series
First page 57
Last page 136
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