Validation of a quantitative assay using GC/MS for trace determination of free and conjugated estrogens in environmental water samples

Abstract

Validation of a quantitative assay using GC/MS for trace determination of free and conjugated estrogens in environmental water samples It has been shown that sewage effluent can discharge human hormones and pharmaceuticals, particularly estrogens and synthetic chemicals, which are able to disrupt animal and human endocrine systems into surface waters. Since many surface waters receive sewage effluent and are subsequently used to produce drinking water, it is of principal interest to assess their contamination level and thereby their possible public health and environmental impact. To date, no data concerning the occurrence of estrogens present in the French aquatic environment are available. We therefore developed and validated an analytical procedure, which allows simultaneous quantitative determination of three natural estrogens, 17b-estradiol, estriol, and estrone and one of the synthetic estrogens most widely used in contraception, ethinylestradiol, in water. Water samples are extracted using solid-phase extraction (SPE) and then separated by gas-chromatography coupled with mass spectrometric detection. Under our conditions, detection limits of estrogens reached the pg range of injected sample, i. e. less than 0.1 ng L -1 . Conjugated estrogens were also investigated using the same procedure as described above but with a enzymatic hydrolysis preliminary step before extraction. The analysis of samples collected from four wastewater treatment plants and from surface water showed significant concentrations of estrogens ranging from 2 to 18 ng L -1 and from 0.5 to 3 ng L -1 , respectively. Furthermore, no estrogen conjugated forms were detected in the water samples.

Simultaneous determination of natural and synthetic steroid estrogens and their conjugates in aqueous matrices by liquid chromatography/mass spectrometry

“…Recoveries for SPE-LC/MS/MS of pesticides in tap and river water observed a matrix related recovery [40] . In another study, no matrix influence was observed on method recoveries when assessed using deionised water and effluent [41] . This study also analysed influent for steroid levels, though no reference is made to method recoveries obtained using this matrix.…”

Pharmaceutical metabolites in the environment: Analytical challenges and ecological risks

“…Due to the poor ionization efficiencies of parent estrogens in LC/MS, they have been analyzed by derivatization followed by GC/MS to obtain better detection limits. A common approach in analyzing estrogen metabolites in environmental samples requires conversion of the estrogen metabolites back to the parent compounds through enzymatic hydrolysis [89,90]. Labadie et al [91] highlighted the differences in preparations of the metabolites for GC/MS analysis.…”

Method validation for the analysis of estrogens (including conjugated compounds) in aqueous matrices

“…[8][9][10][11][12][13][14][15][16][17][18][19][20]. These samples are mostly analysed by liquid or gas chromatography coupled with tandem mass spectrometry (LC-MS/MS or GC-MS/MS).…”

“…Only 2 papers reported results of stability study in solvent extracts [12,15]. Finally, few papers took into account conjugated estrogens [8,14,19,21], despite the fact that it is essential to measure the total quantity of estrogens including the conjugated fraction to assess accurately the concentrations and fluxes of estrogens in the aquatic environment.…”