Suitability of N,O-bis(trimethylsilyl)trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide as derivatization reagents for the determination of the estrogens estrone and 17α-ethinylestradiol by gas chromatography–mass spectrometry

Passive Sampling with Active Carbon Fibres in the Determination of Organic Pollutants in Groundwater

Legislation addressing the quality of groundwater and increasing concerns over public health calls for the development of analytical methods that can produce accurate and precise results at the ppt level. Passive sampling has been recognised as a helpful tool in identifying various organic pollutants in groundwater, even when their presence had not yet been identified through conventional groundwater quality monitoring. The article presents an analytical method involving a simple and cost-effective passive sampling device using Zorflex® activated carbon fibres (ACFs) for the qualitative monitoring of a broad range of organic pollutants in water in a single run. The applicability of the method developed was tested in three hydrogeological studies. In the first case, we present a non-targeted qualitative screening and a list of 892 different contaminants detected in the groundwater in Slovenia. In the second case, we discuss the presence and origin of organic compounds in the groundwater from a pilot area of the urban aquifer, Ljubljansko polje. The third case presents a comparison of results between passive and grab sampling. Passive sampling with ACFs confirmed the presence of a pollutant, even when it had not been previously detected through a quantitative method.

Influence of Calcium Perchlorate on the Search for Martian Organic Compounds with MTBSTFA/DMF Derivatization

N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA), mixed with the solvent N,N-dimethylformamide (DMF), is used as a derivatizing reagent by the Sample Analysis at Mars (SAM) experiment onboard NASA's Curiosity rover and will soon be utilized by the Mars Organic Molecule Analyzer experiment onboard the ESA/Roscosmos Rosalind Franklin rover. The pyrolysis products of MTBSTFA, DMF, and the MTBSTFA/DMF mixtures, obtained at different temperatures, were analyzed. Two different pyrolysis modes were studied, flash pyrolysis and ramp pyrolysis (35°C/min), to evaluate the potential influence of the sample heating speed on the production of products in space chromatographs. The effect of the presence of calcium perchlorate on the pyrolysis products of MTBSTFA/DMF was also studied to ascertain the potential effect of perchlorate species known to be present at the martian surface. The results show that MTBSTFA/DMF derivatization should be applied below 300°C when using flash pyrolysis, as numerous products of MTBSTFA/DMF were formed at high pyrolysis temperatures. However, when an SAM-like ramp pyrolysis was applied, the final pyrolysis temperature did not appear to influence the degradation products of MTBSTFA/DMF. All products of MTBSTFA/DMF pyrolysis are listed in this article, providing a major database of products for the analysis of martian analog samples, meteorites, and the in situ analysis of martian rocks and soils. In addition, the presence of calcium perchlorate does not show any obvious effects on the pyrolysis of MTBSTFA/DMF: Only chloromethane and TBDMS-Cl (chloro-tertbutyldimethylsilane) were detected, whereas chlorobenzene and other chlorine-bearing compounds were not detected. However, other chlorine-bearing compounds were detected after pyrolysis of the Murchison meteorite in the presence of calcium perchlorate. This result reinforces previous suggestions that chloride-bearing compounds could be reaction products of martian samples and perchlorate.

MASS SPECTROMETRIC FRAGMENTATION OF TRIMETHYLSILYL AND RELATED ALKYLSILYL DERIVATIVES

This review describes the mass spectral fragmentation of trimethylsilyl (TMS) and related alkylsilyl derivatives used for preparing samples for analysis, mainly by combined gas chromatography and mass spectrometry (GC/MS). The review is divided into three sections. The first section is concerned with the TMS derivatives themselves and describes fragmentation of derivatized alcohols, thiols, amines, ketones, carboxylic acids and bifunctional compounds such as hydroxy- and amino-acids, halo acids and hydroxy ethers. More complex compounds such as glycerides, sphingolipids, carbohydrates, organic phosphates, phosphonates, steroids, vitamin D, cannabinoids, and prostaglandins are discussed next. The second section describes intermolecular reactions of siliconium ions such as the TMS cation and the third section discusses other alkylsilyl derivatives. Among these latter compounds are di- and trialkyl-silyl derivatives, various substituted-alkyldimethylsilyl derivatives such as the tert-butyldimethylsilyl ethers, cyclic silyl derivatives, alkoxysilyl derivatives, and 3-pyridylmethyldimethylsilyl esters used for double bond location in fatty acid spectra. © 2019 Wiley Periodicals, Inc. Mass Spec Rev 0000:1-107, 2019.

Alkylsilyl derivatives for gas chromatography

Alkylsilyl reagents are the most widely used reagents for the derivatization of polar compounds containing labile hydrogen atoms for gas chromatography. In this article the reagents and reaction conditions for the formation of trimethylsilyl, alkyldimethylsilyl (particularly t-butyldimethylsilyl), cyclic siliconides, haloalkyldimethylsilyl, and flophemesyl (pentafluorophenyldimethylsilyl) derivatives for a wide range of functional groups are reviewed. The importance of steric hindrance on reaction rates and completion, choice of reaction conditions, stability of derivatives, and options for selective detection are described.

Chemiluminescence of CdTe nanocrystals catalyzed by sodium hexametaphosphate and its sensitive application for determination of estrogens

A novel flow injection nanocrystals (NCs) chemiluminescence (CL) analysis method has been established for the determination of estradiol, estriol and estrone based on the enhancement of CdTe NCs-KMnO(4) CL reaction catalyzed by sodium hexametaphosphate. Glutathione (GSH)-capped CdTe nanocrystals were synthesized in aqueous medium, and the CdTe NCs emitted at around 555 nm was selected as the light emitter in CdTe NCs-KMnO(4) chemiluminescence (CL) system. It has been found that sodium hexametaphosphate (SHMP) enhanced the CL of the CdTe NCs-KMnO(4) system and estrogens increased these CL signals again in near neutral solution. UV-visible spectra, photoluminescence (PL) spectra, transmission electron microscopy (TEM) and CL spectra were used to characterize CdTe nanoparticles and investigate the mechanism of the CL reaction. On the basis of the enhancement, a novel flow-injection CL method has been established for the determination of estrogens. Under the optimum experimental conditions, three linear relationships were obtained. The method described is simple, sensitive, and has been successfully utilized for the determination of estrogens in tap water samples.

Influence of 17β-estradiol binding by dissolved organic matter isolated from wastewater effluent on estrogenic activity

The aims of this study were to determine the sorption coefficient (LogK(DOC)) of 17β-estradiol (E2), according to the size and composition of dissolved organic matter (DOM) isolated from wastewater effluent using a fluorescence quenching (FQ) method, and to measure the estrogenic changes due to the extent of E2 sorption onto effluent DOM (EfOM) by using an E-screen bioassay. The highest logK(DOC) of E2 for a DOM size fraction less than 0.2 μm was observed by 4.87 ± 1.87 Lkg(-1)(DOC), and its estrogenicity was the lowest among all the size fractions at 1.2 ng-EEQL⁻¹. However, E2 estrogenicity for a DOM size fraction less than 5 kDa was as high as that for the positive control due to the absence of fulvic acid- and protein-like DOM to bind with E2. The estrogenic activity for the hydrophobic fraction bound with E2 was significantly reduced to 1.6 ng-EEQL⁻¹, while that for the hydrophilic fraction having no binding with E2 was 2.6 ng-EEQL⁻¹, which was similar to that of the positive control (i.e., 2.8 ng-EEQL⁻¹). The results support a conclusion that the change in estrogenicity was due to the strong sorption affinity of E2 onto DOM.

Investigation on the removal of natural and synthetic estrogens using biofilms in continuous flow biofilm reactors and batch experiments analysed by gas chromatography/mass spectrometry

The degradation of the natural estrogen 17β-estradiol and the synthetic steroid hormone 17α-ethinylestradiol, two estrogens already detected in surface waters at low concentration levels, was investigated using continuous flow biofilm reactors and batch experiments. Biofilms in continuous flow experiments were created by natural organisms from river systems of the national park Unteres Odertal, Germany, whereas batch experiments were performed with isolated bacterial strains derived from biofilms. The analytical method, including solid phase extraction, silylation of analytes and measurement with GC/MS, was optimised for the target compounds 17β-estradiol, 17α-ethinylestradiol and the possible metabolites estrone and estriol. The performance characteristics of the analytical method, namely recovery, standard deviations, method detection limits (MDL) and method quantification limits (MQL), were evaluated for accurate interpretation of degradation experiments. Continuous flow biofilm reactors were operated with two different nutrient media under dosage of estradiol and ethinylestradiol. Both estrogens were rapidly degraded within several hours; the metabolite estrone (from estradiol as well as from ethinylestradiol) was detected in significant amounts and was further decomposed. In additional batch experiments using isolated bacterial strains from the natural biofilms to decompose estradiol and ethinylestradiol, different metabolisms of isolates were explored. Five of the 15 isolated bacterial strains tested degraded estradiol and ethinylestradiol with different degradation rates. The results suggest that biofilms from national park Unteres Odertal possess a high capability to aerobically decompose natural and also synthetic estrogens so that these microorganisms could provide enhanced removal of pollutants in municipal water treatment plants.

An alternative method for the determination of estrogens in surface water and wastewater treatment plant effluent using pre-column trimethylsilyl derivatization and gas chromatography/mass spectrometry

A procedure using pre-column trimethylsilyl derivatization and gas chromatography/ mass spectrometry (GC/MS) was developed and applied in determining trace estrogens in complex matrix. Main conditions were optimized, including pH value, salinity of water sample, elution reagents, clean procedure, derivative solvent and temperature. The optimized method was used to determine steroid estrogens in surface water and effluents of wastewater treatment plant (WWTP). Low detection limits of 0.01, 0.03, 0.03, 0.07, 0.09 and 0.13 ng/l for DES, E1, E2, EE2, E3 and E(V), respectively were obtained under optimism condition. No apparent interferences appeared in chromatography in comparison with ultrapure water blank. Mean recovery ranged from 72.6% to 111.0% with relative standard deviation of 1.1-4.6% for spiked surface water, and from 66.6% to 121.1% with relative standard deviation of 1.5-4.7% for spiked effluent of WWTP. The results suggested that the optimized method provides a robust solution for the determination of trace steroid estrogens in complex matrix.

In-drop derivatisation liquid-phase microextraction assisted by ion-pairing transfer for the gas chromatographic determination of phenolic endocrine disruptors

A novel in-drop derivatisation liquid-phase microextraction procedure with an ion-pairing agent is developed and optimised for the extraction of endocrine-disrupting chemicals. The ethyl esters of the analytes were rapidly formed in the organic drop and analysed by gas chromatography. The effects of various parameters such as rate and time of agitation, ion-pairing agent and reactant concentration, pH and temperature were studied systematically to optimise the process and bring out the locale of reaction in the organic drop. A study of the mechanistic pathways of the overall procedure is attempted leading to interesting findings and delineating important points of the kinetics and mechanism. A mechanistic model is proposed on the basis of the theory of mass transfer with chemical reaction in two liquid phases. The O-ethoxycarbonyl derivatisation appears to take place in the bulk organic phase. The system provides insight into the first reported analytical case of single-drop extraction-preconcentration-derivatisation assisted by an ion-pairing transfer and has all of the interesting facets of chemical reaction in which the role of mass transfer comes into picture. The analytical features of the method are acceptable and the overall relative standard deviations of the intra-day repeatability (n=5) and inter-day reproducibility were <3.9% and <5.4%, respectively, for gas chromatography-mass spectrometry analyses and <4.3% and <7.1% for gas chromatography-flame ionisation detection analyses. The method was applicable to urine and surface water samples. The LODs ranged between 0.2-1.3 ng mL(-1) and 8.5-26.5 ng mL(-1) for GC/MS and GC/FID analyses, respectively.

Multiresponse optimization and parallel factor analysis, useful tools in the determination of estrogens by gas chromatography–mass spectrometry

This paper reports an experimental design optimization of a recently proposed silylation procedure that avoids the introduction of false positives and false negatives in the simultaneous determination of steroid hormone estrone (E1) and 17-alpha-ethinylestradiol (EE2) by gas chromatography-mass spectrometry (GC/MS). The figures of merit for several calibration procedures were evaluated under optimum conditions in the silylation step. Internal standardization strategies were applied and global models were constructed by gathering signals recorded on three non-consecutive days. Three calibration models were examined: a univariate model with a sum of six monitorized ions and a three-way PARAFAC-based model (the analyte scores were standardized on the basis of the scores of the internal standard). The global PARAFAC-based calibration model showed the best performance with detection capabilities of 4.3 microg l(-1) and 7.0 microg l(-1) for E1 and EE2, respectively, when the probability of false positives was fixed at 1% and that of false negatives at 5%. Mean relative error in absolute terms for E1 and for EE2 was 11.1% and 8.5%, respectively, and trueness was likewise confirmed. The proposed optimized derivatization procedure using a three-way calibration function was also applied in the determination of E1, 17-beta-estradiol (E2) and EE2 in bovine urine samples: recovery values were 68.5%, 40.4% and 43.4%, respectively, and the detection capability was 18.4, 19.3 and 18.6 microg l(-1) when the probability of false positives was fixed at 1% and that of false negatives at 5%. Mean relative error in absolute terms for E1, E2 and EE2 was 7.4%, 9.4% and 8.6%, respectively, and trueness was likewise confirmed.

Quantification of steroid sex hormones using solid-phase extraction followed by liquid chromatography-mass spectrometry

In this study, the occurrence of trace amounts of natural and synthetic steroid estrogens in the aquatic environment was studied using liquid chromatography coupled with electrospray mass spectrometry, following solid-phase extraction (SPE). The SPE was performed with C18 and NH2 cartridges. The first objective was to develop a reliable method for analyzing steroid estrogens (resulting from human and animal excretions) in different matrices. The method developed was then applied to quantify the occurrence of natural and synthetic hormones (estrone [E1], 17beta-estradiol [betaE2], 17alpha-estradiol [alphaE2], estriol [E3], and 17alpha-ethinylestradiol [EE2]) in environmental samples in surface water and wastewater treatment plant (WWTP) influent and effluent. In the WWTP influents, betaE2, alphaE2, and E3 were identified as ranging up to 72.6 ng/L in WWTP influent and to 16 ng/L in WWTP effluent. Analysis o f surface wa ter sampled upstream from the WWTP revealed the presence of all five estrogens, at levels up to 19.8 ng/L. These concentrations of estrogens pose an issue for large and small communities, because they are higher than the recommended guidelines for estrogen-active compounds and because a lot of communities use surface water as drinking-water sources.

Optimizing gas chromatographic–mass spectrometric analysis of selected pharmaceuticals and endocrine-disrupting substances in water using factorial experimental design

An analytical method based on gas chromatography-mass spectrometry (GC-MS) has been developed to simultaneously determine selected acidic and neutral pharmaceuticals and endocrine-disrupting substances in surface and tap water. Solid-phase extraction (SPE) with Oasis HLB cartridges is followed by derivatization of the target analytes in the eluted extract. Derivatization was systematically optimized by employing a factorial experimental design. More specifically a central composite design was applied to search for the optimal conditions of the derivatization process and it was demonstrated that N-methyl-N-tert-butyl-dimethysilyl-trifluoroacetamide (MTBSTFA) had a better overall performance compared to N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA). The influence of solvent ratios and elution volumes while using SPE were also studied using a factorial design. The method was developed successfully for most of the selected compounds [i.e. ibuprofen, salicylic acid, gemfibrozil, naproxen, triclosan, propranolol, diclofenac, carbamazepine, 4-octylphenol (OP), 4-nonylphenol (NP), nonylphenol-monoethoxylate (NP1EO), nonylphenoxyacetic acid (NP1EC), estrone (E1), and 17alpha-ethinyloestradiol (EE2)]. Relative recoveries for spiked river and tap water ranged from 47 to 130% and 60-109%, respectively. Typical limits of detection were less than 5 ng/L in tap water and less than 10 ng/L in river water. Twelve target compounds were detected in river and tap water samples using the developed method. This method is currently used in bench-scale drinking water treatment studies.

Formation of multiple trimethylsilyl derivatives in the derivatization of 17alpha-ethinylestradiol with BSTFA or MSTFA followed by gas chromatography-mass spectrometry determination

N,O-bis(trimethylsily)trifluoroacetamide (BSTFA) and N-methyl-N(trimethylsily) trifluoroacetamide (MSTFA) are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone (El) and 17alpha-ethinylestradiol (EE2). In this study, three trimethylsilyl (TMS) steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl E1, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz (TMSI) in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.

Optimisation of derivatisation for the analysis of estrogenic compounds in water by solid-phase extraction gas chromatography–mass spectrometry

An optimisation of derivatisation methods for the simultaneous determination of endocrine disrupting chemicals (EDCs) in water by solid-phase extraction (SPE) gas chromatography-mass spectrometry (GC-MS) was developed in this study. Seven highly potent EDCs including 17beta-estradiol (E2), estrone (E1), 16alpha-hydroxyestrone, 17alpha-ethynylestradiol (EE2), bisphenol A, 4-nonylphenol and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used for the extraction recoveries of compounds from water and effluent samples. The stability of the silylation derivatives under different reaction conditions was investigated. The combined use of BSTFA and pyridine as derivatisation reagents, together with the use of hexane as the final solvent, was preferred in order to generate more stable derivatives of EDCs. The relative response factor (RRF) of all derivatives except that of EE2 was stable 120 h after derivatisation. The addition of pyridine as derivatisation reagent with BSTFA can prevent the conversion of EE2 to other products during the reaction. Several parameters that may affect the recovery of EDCs, such as the SPE flow rate, and water properties including aquatic colloid content and surfactant concentration were tested. The results showed that the flow rate (1-25 mL min(-1)), colloid concentration (0-50 mg L(-1)) and surfactants concentration (0-10 microg L(-1)) did not cause significant decrease in the EDCs recovery.

Sensitive gas chromatographic–mass spectrometric method for the determination of phthalate esters, alkylphenols, bisphenol A and their chlorinated derivatives in wastewater samples

Phthalate esters, alkylphenols, bisphenol A and their chlorinated derivatives are the suspected endocrine disrupters or mutagens. These compounds, commonly called endocrine disrupter chemicals (EDCs), are widely used as plastic additives, lacquers, resins, or surfactants and can be usually found in environmental samples, namely wastewaters. An accurate and reproducible gas chromatographic-mass spectrometric (GC-MS) method is proposed to measure these compounds in wastewater samples of Granada city (Spain). A solid-phase extraction with LiChrolut RP-18 cartridges was carried out and the elution was performed with a diethyl ether/methanol mixture. After isolation, solvent was removed and a silylation step was carried out using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Phthalate esters and silylated compounds were identified and quantified by GC-MS using a ZB-5 MS column. Bisphenol F was used as a surrogate. Quantification limits found were between 20 ng L(-1) for 4-nonylphenol and 400 ng L(-1) for benzylbutyl phthalate while inter and intra-day variability was under 5% in all cases. Recoveries for spiked samples were over 95% and under 105%. The method was validated using standard addition calibration and recovery assays.

Occurrence and photochemical degradation of 17alpha-ethinylestradiol in Acushnet River Estuary

17alpha-Ethinylestradiol (EE2), a major constituent of common contraceptive pills, and three other estrogenic hormones, estrone (E1), 17beta-estradiol (E2) and mestranol (MeEE2) have been determined in Acushnet River Estuary seawater using a GC-MS technique. Among three estrogenic compounds detected, EE2 has the highest concentration, up to 4.7 ng/l, at which EE2 may affect lobster and other fish abundance in the coastal seawater due to its high biological activity on fish feminization. Two natural estrogenic hormones, E1 and E2 have also been found in the estuary at concentrations up to 1.2 ng/l and 0.83 ng/l, respectively. Although EE2 is persistent to microbial degradation, it can undergo a rapid photodegradation in estuarine seawater under natural sunlight irradiation, with a half-life of less than 1.5 days in spring sunny days.

Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17α-ethinylestradiol by gas chromatography–mass spectrometry

This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17alpha-ethinylestradiol (EE2) and estrone (E1) using gas chromatography-mass spectrometry (GC-MS). This follows a re-assessment of some of the popular silylation procedures using N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N-O-bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA+1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC-MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions.

Determination of steroids in human plasma using temperature-dependent inclusion chromatography for metabolomic investigations

Clinical and metabolomic investigations of complex human fluids require cost-effective methodologies that can rapidly assess the steroid hormone milieu of individual samples. The efficiency of quantification of many steroids is limited using immunoassays as these methods can only measure a single component of biological samples and are dependent upon the specificity of the antiserum used in the protocol. In this study, we optimised the solid-phase extraction protocol for the extraction of a range of steroids of varied polarity from estetrol to progesterone from human plasma. The final SPE procedure for efficient extraction of steroids was a washing mixture of 5 ml of 30% methanol and an elution solvent of 2 ml of 100% methanol using 0.5 g C-18 cartridges. This protocol resulted in a high recovery rate, ranging from 85.2 to 99.9% for both the internal standard (7,8-dimethoxyflavone) and steroids of interest. We also improved the separation methodology of our previous work using temperature dependent inclusion chromatography with a mobile phase composition of 35% acetonitrile and 12 mM of beta-cyclodextrin at 29 degrees C. Under these conditions most of the fluid components including estetrol were detected in the first 10 min with progesterone appearing at 43 min. This method is simplistic, inexpensive and reproducible with the capabilities of accurate quantification of steroids. Therefore it could have numerous clinical and metabolomic applications.

Polymer-coated hollow-fiber microextraction of estrogens in water samples with analysis by gas chromatography–mass spectrometry

A novel sorbent, dihydroxylated polymethylmethacrylate (DHPMM), coated on hollow-fiber membrane, is used for the polymer-coated hollow-fiber microextraction of trace amounts of natural and synthetic estrogens, such as diethylstilbestrol, estrone, 17beta-estradiol and 17alpha-ethynylestradiol, in aqueous samples. In this procedure, estrogens were extracted using the functionalized polar DHPMM polymer with derivatization using N-methyl-N-(trimethylsilyl)trifluoroacetamide followed by gas chromatography-mass spectrometric analysis. The detection limits for estrogens in aqueous sample were between 0.03 and 0.8 ng l(-1) and the calibration curves were linear over the concentration range 0.05-10 microgl(-1) and had correlation coefficients of >0.994. The relative standard deviations (RSDs) were <15% (n = 3). This simple, accurate, sensitive and selective analytical method is applicable to the determination of trace amounts of estrogens in reservoir and potable water samples.

Occurrence of endocrine-disrupting compounds in reclaimed water from Tianjin, China

Continuous disposal of endocrine-disrupting compounds (EDCs) into the environment can lead to serious human health problems and can affect plants and aquatic organisms. The determination of EDCs in water has become an increasingly important activity due to our increased knowledge about their toxicities, even at low concentration. The EDCs in water samples from the reclaimed water plant of Tianjin, northern China, were identified by gas chromatography (GC)-mass spectrometry (MS). Important and contrasting EDCs including estrone (E1), 17beta-estradiol (E2), 17alpha-ethynylestradiol (EE2), 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl)phthalate (DEHP) were selected as the target compounds. Concentrations of steroid hormones, alkylphenolic compounds and phthalates ranged from below the limit of detection (LOD) to 8.1 ng L(-1), from <LOD to 14.2 ng L(-1), and from 1.00 microg L(-1) to 23.8 microg L(-1), respectively. The average removal efficiencies for target EDCs varied from 30% to 82%. These results indicate that environmental endocrine disrupting compounds are not completely removed during reclaimed water treatment and may be carried over into the general aquatic environment.

Determination of steroidal hormone profiles along the Jalle d'Eysines River (near Bordeaux, France)

Steroidal estrogens have been shown to be the main contributors to the estrogenic activity observed in aquatic systems contaminated with sewage treatment work effluents. Although the occurrence of steroid hormones in the environment has received a great deal of attention, little is known about their fate in aquatic systems. In the presentwork, concentrations of conjugated and unconjugated hormonal steroids (estrone, 17beta-estradiol, estriol, 17alpha-ethynylestradiol, mestranol, progesterone, norethindrone, and D-norgestrel) were determined in the effluent of the Eysines sewage treatment plant (near Bordeaux, France), and along the receiving river, the Jalle d'Eysines River. Sampling was undertaken in summer and in winter conditions, to study both the temporal and the spatial distributions of steroids in this river. Only unconjugated natural estrogens were detected in the effluent. Estrone was the dominant compound (detected in all effluent samples, 17.1-71.0 ng x L(-1)), while estradiol and its metabolite estriol were detected only once, at much lower levels (4.4 and 2.9 ng x L(-1), respectively). Levels of estrogens were clearly raised above the detection limits downstream of the Eysines STP effluent discharge. Seasonal variations of estrone degradation rates were observed. In summer, the apparent decay rates of estrogen levels exceeded that of dilution, indicating high removal rates from the water column: 50% of the initial amount of this steroid was degraded within 1.7 km downstream of the effluent discharge. In winter, however, estrone levels did not significantly decrease over a 10 km reach downstream of the effluent discharge (1.9-1.8 ng x L(-1)). Steroids were determined in the particulate material of the river, but levels were below the detection limits (0.4-1.9 ng x g(-1)), indicating that sorption was not a major sink of estrogens. Therefore, it is likely that biodegradation plays a major role in the removal of steroids from the river and the different decay rates are probably related to differences in bacterial activity within the river.

Comparative study of analytical methods involving gas chromatography–mass spectrometry after derivatization and gas chromatography–tandem mass spectrometry for the determination of selected endocrine disrupting compounds in wastewaters

Two GC-MS methods, based on the application of N,O-bis(trimethylsilyl)trifluoroacetamide-derivatization-GC-MS (selected-ion monitoring) and GC-MS-MS without derivatization, respectively, were optimised and applied to the determination of a group of five selected endocrine disrupting compounds (EDCs) in wastewaters. Both methods included solid-phase extraction with Oasis HLB cartridges allowing an enrichment factor for wastewater samples of 100-fold. The investigated EDCs were estrone, 17beta-estradiol, 17alpha-ethynylestradiol, 4-tert-octylphenol and bisphenol A. Results obtained from the validation studies yielded comparable results in both cases. Recoveries in spiked wastewaters at 50 ng/l were higher than 90% for all the compounds, except for 4-tert-octylphenol (75%). Repeatability and reproducibility were adequate, varying from 1.6 to 14%, except for estrone which reproducibility was 28% when the derivatization-GC-MS method was applied. Limits of detection calculated ranged from 2.5 to 27.5 ng/l with differences between both methods from 1.1 (estrone) to 10.4 (bisphenol A) times. Both methods were successfully applied to the analysis of the target compounds in sewage treatment plant influents and effluents. Traces of bisphenol A, 4-tert-octylphenol, estrone and 17beta-estradiol were detected at concentration levels ranging from 13.3 to 1105.2 ng/l.