Quantitation of estrogens in ground water and swine lagoon samples using solid-phase extraction, pentafluorobenzyl/trimethylsilyl derivatizations and gas chromatography-negative ion chemical ionization tandem mass spectrometry

A method was developed for the confirmed identification and quantitation of 17beta-estradiol, estrone, 17alpha-ethynylestradiol and 16alpha-hydroxy-17beta-estradiol (estriol) in ground water and swine lagoon samples. Centrifuged and filtered samples were extracted using solid-phase extraction (SPE), and extracts were derivatized using pentafluorobenzy] bromide (PFBBR) and N-trimethylsilylimidazole (TMSI). Analysis was done using negative ion chemical ionization (NICI) gas chromatography-mass spectrometry-mass spectrometry (GC-MS-MS). Deuterated analogs of each of the estrogens were used as isotope dilution standards (IDS) and were added to the samples before extraction. A limit of quantitation of 1 ng/l in ground water was obtained using 500 ml of ground water sample, 1.0 ml of extract volume and the lowest calibration standard of 0.5 pg/microl. For a 25 ml swine lagoon sample, the limit of quantitation was 40 ng/l. The average recovery of the four estrogens spiked into 500 ml of distilled water and ground water samples (n = 16) at 2 ng/l was 103% (S.D. 14%). For 25 ml of swine lagoon samples spiked at 500, 1000 and 10,000 ng/l, the average recovery for the four estrogens was 103% (S.D. 15%). The method detection limits (MDLs) of the four estrogens spiked at 2 ng/l in a 500 ml of ground water sample ranged from 0.2 to 0.6 ng/l. In swine lagoon samples from three different types of swine operations, estrone was found at levels up to 25,000 ng/l, followed by estriol and estradiol up to levels at 10,000 and 3000 ng/l, respectively. It was found that pretreatment of swine lagoon samples with formaldehyde was necessary to prevent conversion of estradiol to estrone.     

Derivatization and fragmentation pattern analysis of natural and synthetic steroids, as their trimethylsilyl (oxime) ether derivatives by gas chromatography mass spectrometry: analysis of dissolved steroids in wastewater samples

This paper reports the extension of our multiresidue analysis (MA) procedure with 18 natural and synthetic steroids; permitting the identification and quantification, in total of 81 pollutants from one solution, by a single injection, as their trimethylsilyl (TMS)-oxime ether/ester derivatives, by gas chromatography-mass spectrometry (GC-MS), within 31 min. As a novelty to the field, basic researches, such as fragmentation pattern analysis and derivatization optimization studies were performed for androsterone, transdehydroandrosterone, transandrosterone, mestranol, dihydrotestosterone, ethinylestradiol, testosterone, norethisterone, estriol, 4-androstene-3,17-dione, gestodene, levonorgestrel, etonogestrel, coprostanol, progesterone, cholesterol, medroxy-progesterone-acetate, stigmasterol and β-sitosterol. Results confirmed that (i) the TMS oxime-ether derivatives of the keto steroids provide from 1.40 times (gestodene) up to 4.25 times (norethisterone) higher responses compared to their TMS-ether ones, and (ii) the distribution of syn/anti oximes is characteristic to the ketosteroid species examined. Based on our optimized mass fragmentation, solid phase extraction (SPE) and derivatization studies separations have been performed in the total ion current (TIC) mode, identification and quantification of compounds have been carried out on the basis of their selective fragment ions. Responses, obtained with derivatized standards proved to be linear (hydroxysteroids), or have been calculated from calibration curves (ketosteroids) in the range of 1.88-750ng/L levels. Limit of quantitation (LOQ) values varied between 1.88ng/L and 37.5ng/L concentrations. The most important practical messages of this work are the high androsterone (0.744-4.28μg/L), transandrosterone (0.138-4.00μg/L), coprostanol (2.11-302μg/L), cholesterol (0.308-41μg/L), stigmasterol (1.21-8.40μg/L) and β-sitosterol (1.12-11.0μg/L) contents of influent wastewaters. β-Estradiol (100ng/L) and estriol (54ng/L) were found in one influent sample, only. Reproducibilities, characterized with the relative standard deviation percentages (RSD%) of measurements, varied between 1.73 RSD% (β-estradiol) and 5.4 RSD% (stigmasterol), with an average of 4.82 RSD%.     

Determination and assessment of estradiol-mimicking compounds in the dissolved and particulate phases of wastewater treatment plant samples

During the last two decades, a large number of publications have clearly shown that anthropogenic compounds that disrupt the endocrine system of wildlife species are a major cause for concern, and this concern has led to a demand for new screening methods. In this work, we have optimized and applied a new method to identify endocrine-disrupting chemicals (EDCs), such as nonylphenol, octylphenol, and their corresponding ethoxylates, 17alpha-ethynylestradiol, bisphenol-A, 17beta-estradiol, and estriol, in sewage samples. For the extraction and preconcentration of all analytes from the dissolved and particulate phases, we used SPE and ultrasonic assisted extraction, respectively. Identification and quantification were achieved by HPLC with fluorescence detection. Satisfactory LODs (between 0.5 and 7.6 ng/L in the dissolved phase and 12.3 and 21.4 ng/g in the particulate phase) and analyte recoveries (between 67 and 102%) were achieved for the target compounds. The optimized method was applied to the determination of EDCs in liquid sewage samples collected from July 2009 to July 2010 from a wastewater treatment plant in Las Palmas de G.C. (Spain). Concentrations of EDCs ranged from <10 to nearly 1300 ng/L in the dissolved phase, and from 0.1 to 7.7 microg/g in the suspended particulate matter.     

Liquid chromatography-tandem mass spectrometry analysis of estrogenic compounds in coastal surface water of the Baltic Sea

An analytical method has been developed for the determination of five naturally occurring estrogens (estradiol, estriol, estrone, genistein, daidzein), one synthetic hormone (ethynylestradiol) and three xenoestrogens (4-nonylphenol (NP), 4-tert-octylphenol (4-tert-OP), bisphenol A (BPA)) in coastal marine waters. The procedure includes a solid-phase extraction of approx. fifty litres of water samples on the solid-phase copolymer Oasis HLB followed by a clean-up on silica. Twenty-five percent aliquots were used for the analytical determination of the analytes using high performance liquid chromatography coupled with electrospray-ionisation tandem mass spectrometry (HPLC-ESI-MS/MS). Calculated extraction recoveries between 52 (4-tert-octylphenol) and 91% (nonylphenol) were obtained for the method developed. Matrix interferences occurring during electrospray ionisation were quantified by spiking the extracts prior to the measurements. Method detection limits ranged from 0.02 (estrone) to 1 ng L(-1) (estriol). The method was applied to determine environmental estrogens in coastal waters of the Baltic Sea. The analyses showed the presence of five compounds at levels between 0.10 (estrone) and 17 ng L(-1) (ethynylestradiol).     

Simultaneous determination of degradation products of nonylphenol polyethoxylates and their halogenated derivatives by solid-phase extraction and gas chromatography-tandem mass spectrometry after trimethylsilylation

An efficient method for the simultaneous determination of the degradation products of nonylphenol polyethoxylates (NPnEOs, n = number of ethoxy units), i.e., nonylphenol (NP), NPnEOs (n = 1-3), nonylphenoxy carboxylic acids (NPnECs, n = 1-2, number of ethoxy units plus an acetate) and their halogenated derivatives (XNP, XNP1EO and XNP1EC; X = Br or Cl), in water samples were developed. After trimethylsilylation with N,O-bis(trimethysilyl)acetamide, all the analytes were determined by gas chromatography-tandem mass spectrometry (GC-MS-MS) with electron ionization (EI). The ion peaks of [M - 85]+ of the derivatives were selected as precursor ions and their product ions showing the highest intensities were used for the quantitative analysis. The instrumental detection limits were in the range from 2.1 to 11 pg. The recoveries of the analytes from the water samples were optimized by using solid-phase extraction (SPE). The deuterated reagents of octylphenol, octylphenol monoethoxylate and octylphenoxyacetic acid were used as the surrogates. The method detection limits (500 ml water sample) using C18 SPE were from 2.5 to 18 ng/l. The recoveries from spiked pure water and the environmental water samples were greater than 78%. The method was successfully applied to environmental samples. Remarkably, the concentrations of the halogenated compounds (CINP, CINP1EO and BrNP1EO) were detected at the hundreds of ng/l levels in the Neya river.     

Two polydimethylsiloxane rod extraction methods for the sensitive determination of phenolic compounds in water samples

Simple, precise, and low‐cost methods for the simultaneous determination of phenolic endocrine disrupting compounds such as bisphenol A, trichlorophenol, pentachlorophenol, 4‐nonylphenol, and 4‐octylphenol in water samples were developed. The Direct, in situ derivatization methods are based on polydimethylsiloxane rod extraction followed by liquid desorption and chromatographic analysis by liquid chromatography and diode array detection. Several parameters affecting the extraction and desorption of the phenolic compounds and their acetylated derivates were studied, as well as the chromatographic and detection conditions. For the direct method, determination coefficients (r²) > 0.990 and LODs in the 0.6–2 μg/L range were obtained for all compounds except bisphenol A (9.5 μg/L). With the derivatization‐based method, based on in situ acetylation, lower limits of detection (0.3–0.9 μg/L) were obtained for all the compounds with r² > 0.988 and RSDs in the 2–9% range. The developed methods were applied to the analysis of spiked water samples obtaining recoveries of between 60.2 and 131.7% for the direct method, and of between 76.6 and 108.2% for the derivatization‐based method. The results demonstrate the feasibility of using these two methods for determining bisphenol A, trichlorophenol, pentachlorophenol, 4‐nonylphenol, and 4‐octylphenol in water.     

Determination of steroid sex hormones and related synthetic compounds considered as endocrine disrupters in water by fully automated on-line solid-phase extraction-liquid chromatography-diode array detection

In this study, a procedure for the simultaneous determination in water of six estrogens (estradiol, estriol, estrone, ethynyl estradiol, mestranol, and diethylstilbestrol) and three progestogens (progesterone, norethindrone, and levonorgestrel), selected based on their abundance in the human body, their estrogenic potency, and the extent of their use in contraceptive pills, was developed. The procedure, based on the on-line solid-phase extraction (SPE) of the water sample and subsequent analysis by liquid chromatography/diode array detection (LC/DAD), allows for the monitoring of up to 16 samples in a completely automated, unattended way. The SPE experimental conditions were optimized and the polymeric cartridge PLRP-S selected out of four different cartridges evaluated. The chromatographic separation was carried out on a LiChrospher 100 RP-18 and detection was performed at 200, 225, and 240 nm. The applicability of the method to the analysis of various environmental water samples, including drinking water, groundwater, surface water and sewage treatment plant effluents, was evaluated. Method detection limits were in the range 10-20 ng/l. The method precision and accuracy were satisfactory with recovery percentages ranging from 96 to 111% and relative standard deviations lower than 3%. The technique is also considerably cheap, fast, and easy, and, therefore, very adequate for routing monitoring. To the authors' knowledge it constitutes the first work describing a fully automated, on-line methodology for the continuous monitoring of these compounds in water.     

Analysis of estrogenic contaminants in river water using liquid chromatography coupled to ion trap based mass spectrometry

A precise and reliable method, using liquid chromatography combined with ion trap based mass spectrometry, for the determination of three endogenous estrogens, namely, estrone, estradiol, and estriol, and two synthetic estrogens, ethinyl estradiol and diethylstilbestrol, in environmental water samples was developed. Optimization of the parameter settings of the ion source and mass analyzer as well as evaluation of solvent composition were carried out by continuous introduction of standards through a syringe pump. In negative ion mode the electrospray ionization source gave acceptable results. The optimum solvent used consisted of water/acetonitrile, with no volatile bases or buffers added. A simple, off-line, manual solid-phase extraction method was developed for sample preparation of environmental water samples. Recoveries were over 86% for all compounds. The method was validated and found to be linear, selective, and robust. For analysis of a 50-mL sample, the limit of detection (LOD) ranged from 3.2 to 10.6 ng/L for all compounds, and the limit of quantitation (LOQ) from 10.6 to 35.0 ng/L. Within-day (n = 5) and total (n = 5) reproducibility were investigated at three different concentration levels and ranged from 6.2 to 9.5% and 9.4 to 12.1%, respectively. Finally, the method was applied to real-world samples.     

Determination of 4-alkylphenols by novel derivatization and gas chromatography-mass spectrometry

A simple and sensitive method for the determination of alkylphenols in water samples has been developed using gas chromatography-mass spectrometry. Alkylphenols were determined after the extractive derivatization with pentafluoropyridine. The derivatization of alkylphenols efficiently proceeded to give the corresponding 4-tetrafluoropyridyl derivatives under the biphasic reaction system. The derivatization conditions including the phase-transfer catalyst, the amount of pentafluoropyridine, the reaction time, the concentration of NaOH and organic solvent were optimized. On the mass spectra of these derivatives, intense specific ion peaks were observed: m/z 256 for 4-n-alkylphenols and m/z 284 for 4-tert.-alkylphenols. Calibration curves were linear in the range of 20-1000 ng/l (200-10,000 ng/l for nonylphenol), and the detection limits varied between 6.93 and 15.7 ng/l (85.2 ng/l for nonylphenol). The average recoveries of the alkylphenols in a fortified river water sample (100 ng/l except for nonylphenol: 1000 ng/l) ranged from 91.1 to 112%. The relative standard deviations were found to be between 5.6 and 16%. This method was successfully applied to the determination of alkylphenols in river water.     

液相色谱-电喷雾质谱法同时测定水体中的壬基酚聚氧乙烯醚及其代谢产物

利用液相色谱-电喷雾质谱法同时分析水体中的壬基酚聚氧乙烯醚(NPEOs)及其代谢产物壬基酚聚氧乙烯醚乙酸(NPECs)和壬基酚(NP),用Waters Symmetry ShieldTMRP 18色谱柱,甲醇和乙酸铵溶液作为梯度洗脱的流动相,结果表明3类物质的分离效果良好,并可通过选择离子记录(SIR)模式实现NPEOs和NPECs各单体的定量。仪器的检出限为1~50 pg,选用Oasis HLB小柱进行固相萃取,回收率达75%~98%,平均标准偏差小于12%。该方法用于污水处理厂的水样测定,所取各水样中都测出了NP和NPEOs,并从氧化沟上清液中检测到NPECs。     

Simultaneous determination of the endocrine disrupting compounds nonylphenol, nonylphenol ethoxylates, triclosan and bisphenol A in wastewater and sewage sludge by gas chromatography-mass spectrometry

An integrated analytical method for the simultaneous determination of 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA) and triclosan (TCS) in wastewater (dissolved and particulate phase) and sewage sludge was developed based on gas chromatography-mass spectrometry. Chromatographic analysis was achieved after derivatization with bis(trimethylsilyl)trifluoroacetamide (BSTFA). Extraction from water samples was performed by solid-phase extraction (SPE). The optimization of SPE procedure included the type of sorbent and the type of the organic solvent used for the elution. Referred to solid samples, the target compounds were extracted by sonication. In this case the optimization of the extraction procedure included the variation of the amount of the extracted biomass, the duration and the temperature of sonication and the type of the extraction organic solvent. The developed extraction procedures resulted in good repeatability and reproducibility with relative standard deviations (RSDs) less than 13% for all the tested compounds for both types of samples. Satisfactory recoveries were obtained (>60%) for all the compounds in both liquid and solid samples, except for 4-n-NP, which gave recoveries up to 35% in wastewater samples and up to 63% in sludge samples. The limits of detection (LODs) of the target compounds varied from 0.03 (4-n-NP) to 0.41 microg l(-1) (NP2EO) and from 0.04 (4-n-NP) to 0.96 microg kg(-1) (NP2EO) for liquid and solid samples, respectively. The developed methods were successfully applied to the analysis of the target compounds in real samples.     

Determination of odorous mixed chloro-bromoanisoles in water by solid-phase micro-extraction and gas chromatography-mass detection

A headspace-solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of odorous trihalogenated anisoles in water. Parameters affecting efficiency of HS-SPME procedure, such as the selection of the SPME coating, extraction time, temperature and ionic strength were optimized. The commercially available polydimethylsiloxane (PDMS 100 microm) fiber appears to be the most suitable for the simultaneous determination of these compounds. Run-to-run precision with relative standard deviations (R.S.D.s) between 5 and 15% were obtained for most of the compounds except for 2,5-dicloro-6-bromo-anisole, 2,3-dibromo-6-chloroanisole, pentachloro- and pentabromoanisole (>20%). The method was linear over two orders of magnitude, and detection limits were compound dependent and ranged from 0.03 ng/L for 2,4,6-trichloroanisole to 0.25 ng/L for 2,3-dibromo-6-chloroanisole. The HS-SPME-GC-MS procedure was tested using real samples and relatively good standard deviations were obtained when using p-iodoanisole as internal standard for quantification. This is the first time that the individual identification of odorous trihalogenated chloro-bromoanisoles has been reported, being HS-SPME-GC-MS a suitable method for simultaneous determination of these compounds in water at concentration levels below their odor limit of detection.     

Parts per trillion level determination of endocrine-disrupting chlorinated compounds in river water and wastewater effluent by stir-bar-sorptive extraction followed by gas chromatography–triple quadrupole mass spectrometry

A new analytical method using stir-bar-sorptive extraction (SBSE) followed by liquid desorption (LD) and gas chromatography with triple-quadrupole mass spectrometric detection (GC-QqQ-MS-MS) has been used for quantitative determination of 25 chlorinated endocrine-disrupting compounds (EDCs) in river water and wastewater. The experimental conditions affecting the SBSE-LD performance were studied and are discussed in detail. Results from systematic assay revealed that a 100-mL water sample, stir bars coated with 47?μL PDMS, an extraction time of 14?h (at 900?rpm), 5?% MeOH as modifier and 10?% NaCl resulted in the best analytical recovery of all the target compounds studied. Use of 1:1 ACN-MeOH as back-extraction solvent and two successive sonication steps, each for 5?min, resulted in the best performance for monitoring EDCs in water matrices. The method detection limits for most of the target compounds were very good- ≤?2?ng?L(-1) and ≤10?ng?L(-1) for river water and wastewater effluents respectively. Experimental recovery for all the compounds was >70?%, with the exception of simazine for which recovery from the matrix was 65?%. Signal enhancement observed for a few of the compounds in wastewater effluents was managed by use of matrix-matched standards and different injection liners. The method was successfully used for analysis of river water samples from Henares River (Spain) and wastewater effluent samples from wastewater-treatment plants (WWTP). Eleven of the 25 compounds studied were detected in both river water and wastewater effluents. Terbutylazine and methoxychlor were detected in almost all the river water and effluent samples; amounts varied between 37-58.5?ng?L(-1) and 15.2-46.8?ng?L(-1), respectively. This method was shown enable reliable, effective, and sensitive monitoring of chlorinated EDCs at nanogram levels in surface water and wastewater effluent.     

Comparison of sodium tetraethylborate and sodium tetra(n-propyl)borate as derivatization reagent for the speciation of organotin and organolead compounds in water samples

The influence of pH on the propylation with sodium tetra(n-propyl)borate of butyl- and phenyltins as well as for trimethyl- and triethyllead was investigated. Ethylation and propylation with tetraalkylborates were compared with regard to derivatization yields and figures of merit for organotin compounds in real water samples. Similar results for limit of detection (3–12 ng/L as tin), derivatization yield (40–100%) and relative standard deviation of the method (3–10%) were achieved for derivatization with the two tetraalkylborates. Propylation is thus the preferred method for the simultaneous determination of environmentally relevant organotin and organolead compounds. The handling of the hygroscopic and air sensitive reagents NaBEt₄ and NaBPr₄ was simplified by dissolving them in tetrahydrofurane. The reagent solutions in tetrahydrofurane can be stored for at least one month at ¶4?°C in the dark without observing any decrease in the derivatization efficiency.     

Trace analysis of estrogenic chemicals in sewage effluent using liquid chromatography combined with tandem mass spectrometry

A rapid, selective, sensitive, and reproducible method for the analysis of environmental estrogens, either natural or synthetic, present in samples from sewage treatment works (STW) has been developed. Isolation of these compounds from STWs was performed by applying a simple extraction procedure using an ENVI-CARB cartridge (a graphitized non porous carbon black) as the solid-phase extraction (SPE) system. Liquid chromatography coupled with atmospheric pressure chemical ionization (APCI) and tandem mass spectrometry was used for detection. For the multiple reaction monitoring (MRM) mode, the [M + H](+) ion of estrone and the [M + H-H(2)O](+) ions of 17beta-estradiol, estriol and 17alpha-ethynylestradiol were selected as the precursors for collisionally induced dissociation (CID). The average recoveries from sewage final effluent samples ranged from 84 to 93% for low levels, and from 89 to 95% for high levels. The precision of the method ranged from 11 to 8% for low level and from 9 to 7% for high level samples. The lower level of quantitation for these estrogens in STW samples was determined at 0.5 ng/L for 17beta-estradiol and 17alpha-ethynylestradiol, and 1 ng/L for estrone and estriol, based on 1-L aliquots of sewage treatment works water, using the optimum tuning parameters for each individual selected precursor ion/product ion transition. Compared to a previous gas chromatography/mass spectrometry (GC/MS) method for the analysis of ten STW samples, this method was shown to provide higher sensitivity and lower time consumption.     

Accurate analysis of trace earthy-musty odorants in water by headspace solid phase microextraction gas chromatography-mass spectrometry

A simple and sensitive method was developed for the simultaneous separation and determination of trace earthy-musty compounds including geosmin, 2-methylisoborneol, 2-isobutyl-3-methoxypyrazine, 2-isopropyl-3-methoxypyrazine, 2,3,4-trichloroanisole, 2,4,6-trichloroanisole, and 2,3,6-trichloroanisole in water samples. This method combined headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry and used naphthalene-d(8) as internal standard. A divinylbenzene/carboxen/polydimethylsiloxane fiber exposing at 90°C for 30 min provided effective sample enrichment in HS-SPME. These compounds were separated by a DB-1701MS capillary column and detected in selected ion monitoring mode within 12 min. The method showed a good linearity from 1 to 100 ng L(-1) and detection limits within (0.25-0.61 ng L(-1)) for all compounds. Using naphthalene-d(8) as the internal standard, the intra-day relative standard deviation (RSD) was within (2.6-3.4%), while the inter-day RSD was (3.5-4.9%). Good recoveries were obtained for tap water (80.5-90.6%), river water (81.5-92.4%), and lake water (83.5-95.2%) spiked at 10 ng L(-1). Compared with other methods using HS-SPME for determination of odor compounds in water samples, this present method had more analytes, better precision, and recovery. This method was successfully applied for analysis of earthy-musty odors in water samples from different sources.     

A systematic investigation to optimize simultaneous extraction and liquid chromatography tandem mass spectrometry analysis of estrogens and their conjugated metabolites in milk

In this study, the simultaneous extraction of estrone (E1), 17β-estradiol (E2), estriol (E3), ethinylestradiol (EE2), and their glucuronated and sulfated metabolites in milk was optimized using solid-phase extraction (SPE). The aim of this research was to analyze estrogens and their conjugated metabolites by liquid chromatography with tandem mass spectrometry (LC–MS/MS) in a single run, without the need to perform enzymatic cleavage and derivatization. Two SPE cartridges in tandem were used, consisting of sorbents based on the hydrophilic–lipophilic balance and amine-functionalized packing materials. To monitor analyte loss at every step of the SPE procedure ¹⁴C-labeled E2 was spiked into the milk sample and the radioactivity was monitored at all stages of the SPE. In addition, non-radiolabeled standards of estrogens and metabolites were used to optimize solvent systems for the SPE and LC–MS/MS. The optimized method described in this paper can achieve recoveries ranging from 72% to 117% for the free estrogens (E1, E2, E3, and EE2), and 62% to 112% for seven conjugated metabolites. The three doubly conjugated, highly polar metabolites included in this study gave lower recoveries (≤43%) due to poor retention in SPE. Finally, commercial milk samples were analyzed for the presence of estrogens and their conjugated metabolites. Estrone (concentration range: 23–67 ng/L) was found to be the major free estrogen present in all milk samples. Estradiol was consistently observed in milk, but the concentrations were below the limit of detection (LOD of 10 ng/L), and no estriol and ethinylestradiol were detected. Several conjugated estrogen metabolites were identified, 17β-estradiol-3-glucuronide (71–289 ng/L), estrone-3-sulfate (60–240 ng/L), 17β-estradiol-3,17β-sulfate (<LOD to 30 ng/L), and estrone-3-glucuronide (<LOQ of 25 ng/L). This method proved efficient in the simultaneous analysis of estrogens and their metabolites in milk.     

Solid-phase extraction using molecularly imprinted polymer for selective extraction of natural and synthetic estrogens from aqueous samples

A method is proposed for the clean-up and preconcentration of natural and synthetic estrogens from aqueous samples employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE). The selectivity of the MIP was checked toward several selected natural and synthetic estrogens such as estrone (E1), 17β-estradiol (β-E2), 17α-estradiol (α-E2), estriol (E3), 17α-ethinylestradiol (EE2), dienestrol (DIES) and diethylstilbestrol (DES). Ultrahigh pressure liquid chromatography (UHPLC) coupled to a TSQ triple quadrupole mass spectrometry (QqQ) was used for analysis of target analytes. The chromatographic separation of the selected compounds was performed in less than 2 min under isocratic conditions. The method was applied to the analysis of estrogens in spiked river and tap water samples. High recoveries (>82%) for estrone, 17β-estradiol, 17α-estradiol, estriol and 17α-ethinylestradiol were obtained. Lower but still satisfactory recoveries (>48%) were achieved for dienestrol and diethylstilbestrol. The method was validated and found to be linear in the range 50-500 ng L(-1) with correlation coefficients (R(2)) greater than 0.995 and repeatability relative standard deviation (RSD) below 8% in all cases. For analysis of 100-mL sample, the method detection limits (LOD) ranged from 4.5 to 9.8 ng L(-1) and the limit of quantitation (LOQ) from 14.9 to 32.6 ng L(-1). To demonstrate the potential of the MIP obtained, a comparison with commercially available C(18) SPE was performed. Molecularly imprinted SPE showed higher recoveries than commercially available C(18) SPE for most of the compounds. These results showed the suitability of the MIP-SPE method for the selective extraction of a class of structurally related compounds such as natural and synthetic estrogens.     

The determination of nonylphenol and its precursors in a trickling filter wastewater treatment process

An ultra performance liquid chromatography method coupled to a triple quadrupole mass spectrometer was developed to determine nonylphenol and 15 of its possible precursors (nonylphenol ethoxylates and nonylphenol carboxylates) in aqueous and particulate wastewater matrices. Final effluent method detection limits for all compounds ranged from 1.4 to 17.4 ng?l^?1 in aqueous phases and from 1.4 to 39.4 ng?g^?1 in particulate phases of samples. The method was used to measure the performance of a trickling filter wastewater treatment works, which are not routinely monitored despite their extensive usage. Relatively good removals of nonylphenol were observed over the biological secondary treatment process, accounting for a 53 % reduction. However, only an 8 % reduction in total nonylphenolic compound load was observed. This was explained by a shortening in ethoxylate chain length which initiated production of shorter polyethoxylates ranging from 1 to 4 ethoxylate units in length in final effluents. Modelling the possible impact of trickling filter discharge demonstrated that the nonylphenol environmental quality standard may be exceeded in receiving waters with low dilution ratios. In addition, there is a possibility that the EQS can be exceeded several kilometres downstream of the mixing zone due to the biotransformation of readily degradable short-chained precursors. This accentuates the need to monitor ‘non-priority’ parent compounds in wastewater treatment works since monitoring nonylphenol alone can give a false indication of process performance. It is thus recommended that future process performance monitoring and optimisation is undertaken using the full suite of nonylphenolic moieties which this method can facilitate.     

Simultaneous determination of benzophenone-type UV filters in water and soil by gas chromatography-mass spectrometry

A novel method has been developed to simultaneously determine and quantify seven organic UV filters employing liquid (solid)-liquid extraction, derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) and gas chromatography with mass spectrometric detection in various environmental matrices. The UV filters determined were: benzophenone (BP), benzhydrol (BH), 4-hydroxybenzophenone (HBP), 2-hydroxy-4-methoxybenzophenone (HMB), 2,4-dihydroxybenzophenone (DHB), 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxylbenzophenone (THB). Under optimal conditions, the analysis required 23 min and good linearity over the range of 10-2,500 ng/L in water and 100-25,000 ng/kg in soil for each UV filter obtained. The high recovery (62-114% and 60-125% for water and soil samples, respectively) and the low RSD values (less than 13.9 and 17.2% for water and soil samples, respectively) indicated the high performance of this method. The method detection limits (MDLs) were relatively low, ranging from 5 to 100 ng/L or kg and quantification limits ranged between 25 and 500 ng/L or kg for all test compounds. This validated method was applied in the analysis of seven BP-type UV filters collecting water and soil samples in Korea, between April and May 2003. The overall concentration of UV filters in the soil sample (500-18,380 ng/kg) was highly distributed in water sample (27-204 ng/L). The established method was successfully applied to monitor the residue measurement of the BP-type UV filters in environmental water and soil samples.