Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction-gas chromatography-mass spectrometry

A solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples has been developed, based on the sorption of target analytes on a selectively sorptive fibre and subsequent desorption of analytes directly into GC-MS. The influence of various parameters on PAH extraction efficiency by SPME was thoroughly studied. Results show that the fibre exposure time and the use of agitation during exposure are critical in enhancing SPME performance. The presence of colloidal organic matter (as simulated by humic acid) in water samples is shown to significantly reduce the extraction efficiency, suggesting that SPME primarily extracts the truly dissolved compounds. This offers the significant advantage of allowing the differentiation between freely available dissolved compounds and those associated with humic material and potentially biologically unavailable. The method showed good linearity up to 10 μg/l. The reproducibility of the measurements expressed as relative standard deviation (R.S.D.) was generally <20%. The method developed was then applied to extract PAHs from sediment porewater samples collected from the Mersey Estuary, UK. Total PAH concentrations in porewater were found to vary between 95 and 742 ng/l with two to four ring PAHs predominating. Results suggest that SPME has the potential to accurately determine the dissolved concentrations of PAHs in sediment porewater.     

Assessment of the occurrence and distribution of pharmaceuticals in a Mediterranean wetland (L'Albufera, Valencia, Spain) by LC-MS/MS

The distribution of 17 pharmaceuticals between water and the solid phase (sediments and soils) was studied by utilizing solid-phase extraction (SPE) and liquid chromatography?Ctandem mass spectrometry (LC-MS/MS). Two extraction procedures for soils and sediments, prior to the SPE, one based on pressurized liquid extraction (PLE) with hot water and the other on methanol/water ultrasonic extraction, were compared. Absolute recoveries were 71.2?C99.3% [relative standard deviation (RSD) <21.4%)] for water, and the method detection limits (MDLs) ranged from 0.3 to 10?ng?L^?1. Recoveries were 35.4?C105.3% (RSDs <19.1%) and 42.1?C97.8% (RSDs <14%) for soil and sediment samples, respectively, using PLE and 20.2?C86.5% (RSDs <25.1%) and 30.3?C97.4% (RSDs <19.1%) using ultrasonic extraction. Fifteen of the 17 pharmaceuticals were present in the L??Albufera water at concentrations up to 17???g?L^?1. Oxytetracycline and tetracycline were not detected. In sediments, only tetracycline, norfloxacin and diclofenac were not found. The other studied pharmaceuticals were present in the range from less than the method quantification limit (MQL) to 35.83?ng?g^?1. Among the 17 target compounds, ofloxacin, ciprofloxacin, norfloxacin, trimethoprim, clofibric acid and diclofenac were not detected in soil samples. The average concentrations ranged from less than the MQL for ibuprofen to 34.91?ng?g^?1 for tetracycline. These results indicate that pharmaceuticals could survive the wastewater treatment processes, which could lead to their dissemination in water environments.     

Determination of biocides in different environmental matrices by use of ultra-high-performance liquid chromatography–tandem mass spectrometry

A sensitive and robust method using solid-phase extraction and ultrasonic extraction for preconcentration followed by ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS–MS) has been developed for determination of 19 biocides: eight azole fungicides (climbazole, clotrimazole, ketoconazole, miconazole, fluconazole, itraconazole, thiabendazole, and carbendazim), two insect repellents (N,N-diethyl-3-methylbenzamide (DEET), and icaridin (also known as picaridin)), three isothiazolinone antifouling agents (1,2-benzisothiazolinone (BIT), 2-n-octyl-4-isothiazolinone (OIT), and 4,5-dichloro-2-n-octyl-isothiazolinone (DCOIT)), four paraben preservatives (methylparaben, ethylparaben, propylparaben, and butylparaben), and two disinfectants (triclosan and triclocarban) in surface water, wastewater, sediment, sludge, and soil. Recovery of the target compounds from surface water, influent, effluent, sediment, sludge, and soil was mostly in the range 70–120?%, with corresponding method quantification limits ranging from 0.01 to 0.31?ng?L^?1, 0.07 to 7.48?ng?L^?1, 0.01 to 3.90?ng?L^?1, 0.01 to 0.45?ng?g^?1, 0.01 to 6.37?ng?g^?1, and 0.01 to 0.73?ng?g^?1, respectively. Carbendazim, climbazole, clotrimazole, methylparaben, miconazole, triclocarban, and triclosan were detected at low ng?L^?1 (or ng?g^?1) levels in surface water, sediment, and sludge-amended soil. Fifteen target compounds were found in influent samples, at concentrations ranging between 0.4 (thiabendazole) and 372?ng?L^?1 (methylparaben). Fifteen target compounds were found in effluent samples, at concentrations ranging between 0.4 (thiabendazole) and 114?ng?L^?1 (carbendazim). Ten target compounds were found in dewatered sludge samples, at concentrations ranging between 1.1 (DEET) and 887?ng?g^?1 (triclocarban).     

Methylated arsenic species in estuarine porewaters

Inorganic arsenic, monomethylarsenic and dimethylarsenic species have been observed in samples of sediment porewater collected from the Tamar Estuary in South-West England. Porewater samples were collected using in situ dialysis. The arsenic species were separated by hydride generation and concentrated by liquid nitrogen trapping, prior to analysis by directly coupled gas chromatography-atomic absorption spectroscopy. The predominant dissolved arsenic species present was inorganic arsenic (5-62 m?g dm^?3). However, this is the first time significant concentrations of methylated arsenic species have been quantified in estuarine porewaters (0.04–0.70 m?g dm^?3), accounting for between 1 and 4% of the total dissolved arsenic. The presence of methylated arsenic compounds in porewaters is attributed to in situ environmental methylation, although the possibility of methylated arsenic species being derived from biological debris cannot be excluded.     

Determination of trace PAHs in seawater and sediment pore-water by solid-phase microextraction (SPME) coupled with GC/MS

A fast and reliable method for the determination of trace PAHs (polynuclear aromatic hydrocarbons) in seawater by solid-phase microextraction (SPME) followed by gas chromatographic (GC) analysis has been developed. The SPME operational parameters have been optimized, and the effects of salinity and dissolved organic matter (DOM) on PAHs recoveries have been investigated. SPME measures only the portion of PAHs which are water soluble, and can be used to quantify PAH partition coefficient between water and DOM phases. The detection limits of the overall method for the measurement of sixteen PAHs range from 0.1 to 3.5 ng/g, and the precisions of individual PAH measurements range from 4% to 23% RSD. The average recovery for PAHs is 88.2±20.4%. The method has been applied to the determination of PAHs in seawater and sediment porewater samples collected in Jiaozhou Bay and Laizhou Bay in Shandong Peninsula, China. The overall levels of PAHs in these samples reflect moderate pollution compared to seawater samples reported elsewhere. The PAH distribution pattern shows that the soluble PAHs in seawater and porewater samples are dominated by naphthalenes and 3 ring PAHs. This is in direct contrast to those of the sediment samples reported earlier, in which both light and heavy PAHs are present at comparable concentrations. The absence of heavy PAHs in soluble forms (<0.1-3.5 ng/L) is indicative of the strong binding of these PAHs to the dissolved or solid matters and their low seawater solubility.     

Occurrence of synthetic hormones in sewage effluents and Langat River and its tributaries,Malaysia

This study investigated for the first time the occurrence of selected synthetic hormones including 17α-ethinylestradiol, levonorgestrel, norethindrone and cyproterone acetate in Malaysian tropical waters. Samples were collected from the effluents of five sewage treatment plants (STPs) and at seven stations along the Langat River in Selangor, Malaysia, and its main tributaries. Samples were extracted by solid phase extraction (SPE) and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). In Langat river samples, only levonorgestrel and cyproterone acetate were found at 50% and 3.3% frequency. The concentrations detected for levonorgestrel ranged from less than the method detection limit (<MDL) to 213?ng?L^?1 and from?<?MDL to 76?ng?L^?1 for cyproterone acetate. For the STP effluent samples, levonorgestrel was <MDL in all samples and the concentrations detected were in the range?<?MDL – 262?ng?L^?1 for cyproterone acetate,?<?MDL ?11336?ng?L^?1 for norethindrone and?<?MDL – 1898?ng?L^?1 for 17α-ethinylestradiol.     

Ultrasound-Assisted Dispersive Liquid�CLiquid Microextraction Combined with Low Solvent Consumption for Determination of Polycyclic Aromatic Hydrocarbons in Seawater by GC�CMS

Ultrasound-assisted dispersive liquid?Cliquid microextraction (USA-DLLME) with low solvent consumption was demonstrated for gas chromatography-mass spectrometry (GC?CMS) determination of 16 typical polycyclic aromatic hydrocarbons (PAHs) in seawater samples. Factors affecting the extraction process, such as extraction and dispersive solvent, phase ratio, temperature, extraction and centrifugation time, were investigated thoroughly and optimized. The linear range was 20?C2,000 ng L^?1 except for acenaphthylene (Acy) at 10?C2,000 ng L^?1 and phenanthrene (Phe), fluoranthene (Flu) and pyrene (Py) all at 5?C2,000 ng L^?1. Enrichment factors (EFs) ranging from 722 to 8,133 were obtained, achieving limits of detection at 1.0?C10.0 ng L^?1. The method attained good precision (relative standard deviation, RSD) from 3.4 to 14.2% for spiked 50 ng L^?1 individual PAHs standards. Method recoveries were in the range 87?C124% and 70?C127% for spiked samples from simulated seawater and beach seawater, respectively. The proposed USA-DLLME helped to obtain about 1.1?C10 times higher EFs in a minimum amount of solvent and in less time than traditional DLLME.     

Occurrence of organochlorine pesticides and polychlorinated biphenyls in soils and sediments from Eastern Romania

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), such as DDT and analogues, hexachlorocyclohexane (HCH) isomers and hexachlorobenzene (HCB), were measured in surface soils and sediments from Eastern Romania. Thirty-nine soil samples from the forested zone, eight soil samples from a municipal waste-disposal site, and 10 sediment samples from the Bahlui River along the Iassy city were analysed using accelerated solvent extraction (ASE) and gas chromatography coupled to electron capture detection or mass spectrometry. The low mean concentrations of OCPs (11–31 and 22–84?ng?g^?1 for HCHs and DDTs, respectively) and PCBs (8–43?ng?g^?1) in soil samples from the forested zone suggest that contamination at most of these sites occurred predominantly through atmospheric transport from zones where these compounds were used and subsequently through atmospheric deposition. Contrarily, soil samples collected in the vicinity of a waste-disposal site near Iassy contained higher mean levels of PCBs (278?ng?g^?1, range 34–1132?ng?g^?1) than OCPs (6 and 101?ng?g^?1 of soil for HCHs and DDTs, respectively). The sediment samples collected along the Bahlui river throughout the Iassy city revealed higher mean levels of PCBs (59?ng?g^?1, range 24–158?ng?g^?1) compared with OCP levels (2 and 37?ng?g^?1 of soil for HCHs and DDTs, respectively). Furthermore, PCB profiles and concentrations in the sediment samples varied considerably along the river due to a wide variety of sources, such as different industries and waste sites. Although their sources are difficult to evaluate, the presence of POPs at most sites (especially at the waste-disposal site) may constitute a potential health hazard.     

Multi-determination of organic pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multi-determination method has been developed for the determination and confirmation of 68 organic pollutants in water samples by gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS). The following chemical families were determined in a chromatographic run of less than 26?min: polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenylethers (PBDEs), and pesticides (organochlorine, organophosphorus, triazine and others). The sample preparation involved a liquid-liquid extraction (LLE) procedure, obtaining recoveries ranging from 70 to 130% when dichloromethane was used as the extracting solvent. The detection limits of the proposed method were between 0.75 and 19.8?ng?L^?1. Samples from the Maipo River in central Chile were taken from 29 different points. Seven pesticides and two PAHs were detected in field collected samples with concentrations ranging from 10 to 95?ngL^?1. Concentrations of benzo[a]pyrene in environmental samples ranged from 25 to 33?ngL^?1 and were near the maximum levels established by the European Union Directives (50?ng?L^?1).     

Rapid and simplified method for the quantitative analysis of polycyclic aromatic hydrocarbons, lipid biomarkers and organochlorine compounds in marine settling particles

We report on a distinctly improved method for the determination of polycyclic aromatic hydrocarbons (PAHs), lipid biomarkers and organochlorine compounds (OCs) in sediment trap studies involving large numbers of samples of limited particle amounts (20–50?mg). It is based on gas chromatography hyphenated to mass spectrometry. One protocol enables analysis of PAHs and lipids, the other that of the OCs. Both have identical extraction and clean-up procedures, the first involving alkaline hydrolysis and the latter hydrolysis with concentrated sulfuric acid. The limits of detection and quantification for PAHs are 0.1–5.7 and 0.1–9.5?ng?g^?1, respectively. For lipids, they are 0.01–0.12 and 0.01–0.21?μg?g^?1, and for OCs they are 0.1–1.0 and 0.3–1.1?ng?g^?1. The method was applied to sediment traps deployed in the northwestern Mediterranean and provided useful fingerprints to understand sources, ways of transport and fates of these species.

Determination of polynuclear aromatic hydrocarbons in environmental samples by Micellar liquid chromatography

A method for the separation of polycyclic aromatic hydrocarbons (PAHs) by high-performance liquid chromatography using a hybrid micellar mobile phase is described. The detection of PAHs was carried out using the fluorescence method with programmable excitation and emission wavelength. The method is applied to the analysis of several environmental samples (sea water, sediments, limpets, sea worms) and several of these compounds are quantitated at concentration below 70 ng L⁻¹(kg⁻¹) in the original samples.     

Quantitative Speciation of Arsenic in Water and Sediment Samples from the Mokolo River in Limpopo Province,South Africa

The Mokolo River is disposed to environmental contaminants such as arsenic (As) due to its proximity to several anthropogenic activities. Speciation of As in water and sediment samples from Mokolo River is crucial to evaluate the level and distribution of As in the river and underlying sediment since toxicity depends on its chemical forms. In this study, As species in water and sediment were determined by developing a new method for sediment extraction. Effective microwave-assisted extraction of As species in sediment samples was achieved using 0.3?M (NH₄)₂HPO₄ and 50?mM EDTA, which showed no species interconversion during extraction. The chromatographic separation and detection of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid, and As(V) in water and sediment samples were achieved by coupling to high-performance liquid chromatography to inductively coupled plasma mass spectrometry. Baseline separation of four As species was achieved in 12?min using gradient elution with 10 and 60?mM NH₄NO₃ at pH 8.7 as the mobile phase. The analytical figures of merit and validation of analytical procedures were assessed and adequate performance and percentage recoveries ranging from 81.1 to 102% for water samples and 73.0–92.0% for sediments were achieved. The As species concentration in water and sediment samples was found to be in the range of 0.304–4.99?µg?L^?1 and 74.0–92.0?ng?g^?1, respectively. DMA was not detected in both water and sediment samples.     

Spatial and seasonal behaviour of organotin compounds in protected subtropical estuarine ecosystems in Okinawa,Japan

The spatial and temporal behaviours of the organotin compounds (OTCs) (butyl- and phenyltin) were investigated in the Manko and Okukubi protected estuarine ecosystems on Okinawa Island, Japan from February to October 2006. Butyltin compounds (BTCs) were frequently detected in all seasons, while phenyltin (PhTs) were found in winter and early spring. In Manko estuary, the total mean concentrations of BTCs and PhTs were 22.78?±?30.85, (mean?±?SD, n?=?53) and 0.08?±?0.27?ng(Sn)?L^?1, respectively. In Okukubi estuary, BTCs and PhTs were 12.58?±?23.96 and 0.47?±?1.67 (n?=?55) ng(Sn)?L^?1, respectively. The Manko sediments can be classified as lightly contaminated, while the Okukubi sediments were uncontaminated with tributyltin (TBT). The mean levels of TBT shown in Manko estuary exceeded the threshold level and represent an ecotoxicological risk to sensitive aquatic life. Generally, the present study reports the occurrence and continuous input of OTCs in the protected estuaries, even 16 years after legal restriction of TBT usage in coastal waters was implemented by the Japanese Environmental Authorities.     

Survey of concentration of polycyclic aromatic hydrocarbons in lake balaton by HPLC with fluorescence detection

Summary Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in water and sediment samples at 15 sites in Lake Balaton during three sampling campaigns in 1996. PAHs were concentrated from water samples by solid phase extraction. Sediment samples were extracted with acetone in an ultrasonic bath then cleaned by solid phase extraction. The total concentration of PAHs ranged from 30–360 ng g⁻¹ and from 170–720 ng L⁻¹ in sediment and water samples, respectively. Spatial and temporal variations of the concentration of PAHs were also investigated. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.     

Ultra-trace determination of aquaculture chemotherapeutants and degradation products in environmental matrices by LC-MS/MS

Two of the most common products currently used to control parasitic sea lice in fin fish aquaculture, salmon in particular, are Slice® and AlphaMax®. Emamectin benzoate (EB) is the active ingredient in Slice® and deltamethrin is the active ingredient in AlphaMax®. Several analytical methods have been developed for the determination of the active ingredients in these products but these have been focused on specific matrices and lack the sensitivity and versatility required in environmental monitoring. Here we present a validated, versatile, and simple analytical method for the determination of EB, its desmethyl degradation product (AB), and deltamethrin in a wide range of environmental matrices (sea water, marine sediment, and tissue). Sediments and tissues were extracted by accelerated solvent extraction (ASE®) and sample cleanup was achieved by solid phase extraction (SPE) while sea water was extracted using SPE disks. Analyte identification and quantification was based on liquid chromatography tandem mass spectrometry (LC-MS/MS) instrumentation with electrospray ionization, and multiple reaction monitoring (MRM). Method detection limits for the target analytes was in the parts per trillion (pg?g^?1) level for tissue and sediment and parts per quadrillion (pg?L^?1) for water. Except for deltamethrin in sea water, method performance in terms of analyte recoveries was better than 60%, and the method precision was RSD<20%. The method was used to determine EB and AB concentrations in water, sediment and prawn tissue samples collected near salmon aquaculture sites treated with Slice®. A distinct concentration gradient was observed in the immediate vicinity (within 50 to 100?m radius) of the salmon aquaculture sites where EB was detected at low ng?g^?1 levels for tissue (EB ranged from 0.041 to 3.0?ng?g^?1) and sediment (EB ranged from 0.051 to 35?ng?g^?1) and pg?L^?1 levels (EB ranged from 3 to 209?pg?L^?1) for water samples.     

Determination of monohydroxylated metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) from wastewater-treatment plants

A high-performance liquid chromatography separation coupled with mass spectrometry via an electrospray interface is proposed for the determination of the hydroxylated derivatives of polycyclic aromatic hydrocarbons (OH-PAHs) in treated and untreated wastewaters and suspended solids from sewage treatment plants (STPs). The developed SPE procedure was applied to spiked wastewater samples, with recovery yields (1000?mL; 100?ng?L^?1 spiking level) in the 65–87% (RSD: 6–12%) range for the selected OH-PAHs. The limits of detections ranged between 0.3 and 3.2?ng?L^?1, depending on the selected compound and on the investigated matrix. The proposed method was applied to the determination of the selected analytes in real samples from a sewage-treatment plant (STP). The investigated OH-PAHs were detected mainly in the particulate fraction. The exhibited mean concentrations of positive samples (as the sum of dissolved and particulate matter) in the STP final effluent ranged from 15 to 68?ng?L^?1.     

Polycyclic aromatic hydrocarbon and ionic compositions of atmospheric bulk deposition samples at a national park under the influence of intense barbecue smoke

The main aim of this study was to present the effects of barbecue smoke on a small-scale environment, a national park under the influence of intense barbecue smoke, and to scientifically support the sustainable usage of the park. Twelve-weekly bulk deposition samples were collected directly at the barbecuing area, and the samples were analysed for 16 US EPA’s priority PAH compounds and major ions. The mean concentrations of the individual PAHs in the bulk deposition samples ranged from 11.8 ng L^?1 (Ane) to 1085 ± 581 ng L^?1 (IcdP). The most frequently observed PAH compounds in the bulk deposition samples were Np, Anp, Flr, Phe, An, Flu, BkF, BaP and IcdP. The mean total PAH deposition fluxes were determined as 3.6 ± 5.6 µg m^?2 day^?1. The chloride, potassium and the sulphate fluxes were determined as 145.2 ± 267.8 µg m^?2 day^?1, 182.9 ± 291.9 µg m^?2 day^?1, and 111.9 ± 65.9 µg m^?2 day^?1, respectively. Dominant ions in the bulk deposition samples were potassium ion, chloride and sulphate which addressed as the fingerprint of barbecue grilling.     

Trace analysis of benzophenone-derived compounds in surface waters and sediments using solid-phase extraction and microwave-assisted extraction followed by gas chromatography–mass spectrometry

This study describes a procedure for determining eight benzophenone-derived compounds in surface waters and sediments. These include the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-acetylbenzophenone, and five benzophenone-type ultraviolet (UV) filters. The proposed analytical method involves the pre-concentration of water samples by solid-phase extraction (SPE) and microwave-assisted extraction (MAE) of sediment samples followed by derivatization and analysis by gas chromatography–mass spectrometry. Different parameters were investigated to achieve optimal method performance. Recoveries of 91 to 96 % from water samples were obtained using HLB Oasis SPE cartridges, whereas MAE of sediments (30 min at 150 °C) gave recoveries of 80 to 99 %. Limits of detection were between 0.1 and 1.9 ng L^?1 for water samples and from 0.1 to 1.4 ng g^?1 for sediment samples. The developed method was applied to environmental samples and revealed the presence of UV filters in the majority of the surface waters with up to 690 ng L^?1 of 2-hydroxy-4-methoxybenzophenone. By contrast, ketoprofen (≤2,900 ng L^?1) and its degradation products (≤320 ng L^?1) were found in only two rivers, both receiving wastewater treatment plant effluents. Sediment analysis revealed benzophenone to be present in concentrations up to 650 ng g^?1, whereas concentrations of other compounds were considerably lower (≤32 ng L^?1). For the first time, quantifiable amounts of two ketoprofen transformation products in the aqueous environment are reported.     

Determination of Florfenicol in Freshwater, Sediments and Bryophyte Fontinalis antipyretica by HPLC with Fluorescence Detection

Novel procedures for the determination of florfenicol in freshwater, sediments and bryophyte Fontinalis antipyretica, using reversed-phase high-performance liquid chromatography are described. Liquid chromatography was performed on a 5 µm PuroSpher RP-18E^® column using methanol and 0.05 M phosphate buffer (18/82 v/v, pH 7.3) as mobile phase (0.8 ml min^?1) and fluorescence detection (excitation wavelength 265 nm and emission wavelength 295 nm). Florfenicol was determined in centrifuged freshwater samples. Florfenicol was extracted from sediments and bryophytes samples by using a solid-liquid extraction step followed by a solid phase extraction step. Linearity was confirmed over the concentration range 25–1000 ng mL^?1 water and 50-1000 ng g^?1 sediment or bryophyte. Limits of detection and quantitation were 8 and 25 ng mL^?1 water and 17 and 50 ng g^?1 sediment or bryophyte respectively. Mean extraction recoveries of florfenicol from sediments and bryophyte were from 85.9 to 109.1%.     

Development and optimisation of a GC-MS method for the evaluation of oestrogens and persistent pollutants in river and seawater samples

This paper describes the development and validation of a GC-MS method which allows the simultaneous quantification of 11 endocrine disrupting compounds (EDCs) in surface water samples from both estuary and sea. The analysed EDCs are oestrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-tert-octylphenol, 4-n-octylphenol, 4-nonylphenol, bisphenol A and finally, mono and diethoxylates of 4-nonylphenol and 4-octylphenol. The method includes the pre-concentration of water samples, 1000-fold factor, in OASIS HLB cartridges by solid phase extraction, the derivatisation of all EDCs by N,O-bis(trimethylsilyl)trifluoroacetamide added with 1% trimethylchlorosilane and pyridine (at 65°C for 30?min) and, finally the stabilisation of the EDCs-silylated derivatives, in hexane, for 72?h. The validation parameters revealed that this method was highly specific for all target compounds using real samples. The linearity of the calibration curves (r ²) showed correlation factors higher than 0.990. The detection limits ranged from 0.10 to 1.45?ng?L^?1, depending on each analysed compound, and recoveries were satisfactory for most of the assayed EDCs (>60%). Analysis of samples from four polluted areas of Douro River estuary and from two points of the Atlantic Ocean (Portugal) showed high amounts of E1 (up to 1.96?ng?L^?1), E2 (up to 14.36?ng?L^?1) and EE2 (up to 2.76?ng?L^?1).