Stir Bar Sorptive Extraction Thermal Desorption Gas Research Articles

Determination of fipronil and its three degradates in water using stir bar sorptive extraction–thermal desorption–gas chromatography–tandem mass spectrometry

A method was developed for determination of fipronil (FIP) pesticide and its three major degradates (fipronil desulfinyl, fipronil sulfide, fipronil sulfone) in water at the levels required by the EU Commission in the Decision 2022/1307. The method combines solvent-free stir bar sorptive extraction (SBSE) with thermal desorption–gas chromatography–tandem mass spectrometry (TD–GC–MS/MS). Simple sample processing involves 16 h of stirring a 100 mL water sample with a polydimethylsiloxane-coated sorptive stir bar, followed by TD of the trapped analytes into the GC. The greenness assessment by analytical Eco-Scale approach resulted in classification of the entire analytical method as "an excellent green analysis". The obtained limits of quantification for all FIPs determined in tap, lake, MilliQ water and artificial seawater were in the range of 0.12–0.30 ng L–1. The recoveries ranged between 81.7 and 109% with relative standard deviations from 2.8 to 14%. The results show that the method is suitable for screening and monitoring the studied analytes in selected matrices.

Anthropogenic Occurrence of Phthalate Esters in Beach Seawater in the Southeast Coast Region, South Korea

In modern times, humans have contributed to the occurrence of phthalate esters (PEs) in various environmental matrices by consuming plastics that generally contain PEs, which are essential synthetic organic chemicals for fabrication of various consumer products. Five beaches in Ulsan and Busan, South Korea, were investigated for the anthropogenic occurrence of four PEs (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and bis(2-ethylhexyl) phthalate (DEHP)) in beach seawater. Using stir-bar sorptive extraction-thermal desorption-gas chromatography/mass spectrometry, DnBP and DEHP were determined as generally dominant. At Ilsan Beach, both the northern and southern ends showed higher DnBP and DEHP concentrations than the middle of the beach, while DMP and DEP showed similar concentrations at all points. The differences in the DnBP and DEHP concentrations may be related to the fishery industry and domestic sewage inflow to the beach. In addition, a comparison among Ilsan, Imnang, and Songjeong beaches suggested the effects of neighboring industrial areas on the DnBP and DEHP ratio. This study provides information on the effects of seasons, weather events, the proximity of rivers, industrial behavior, and domestic sewage to PE concentrations in beach seawater.

Determination of booster biocides in sediments by focused ultrasound-assisted extraction and stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

Booster biocides present in natural waters may be captured by the sediments. Highly sensitive, robust, selective and reliable analytical methods are required to evaluate their presence in the sediments. A focused ultrasound assisted extraction method for the simultaneous determination of five organic booster biocides (Chlorothalonil, Dichlofluanid, Sea-Nine 211, Irgarol 1051 and TCMTB) in marine sediments is proposed. The isolation of the target compounds from 0.5 g of sediment was efficient using 2.5 mL of methanol as solvent, an output amplitude of 50 W, 100% duty cycle and an extraction time of 300 s. The extraction procedure was followed by solid-phase clean-up on non-polar sorbents (Oasis HLB). The compounds were sampled using stir bars (20 mm length, 0.5 mm film thickness) coated with polydimethylsiloxane (PDMS). The stir bars were stirred at 900 rpm for 3 h at room temperature. Desorption was carried out by thermal desorption (TD), and the analytes were separated in the gas chromatography (GC). They were detected by triple quadrupole mass spectrometry (MS/MS) using the multiple reaction monitor (MRM) mode. The detection limits (DLs) of booster biocides were in the range of 0.02 to 2.2 ng g − 1 dry weight. The regression coefficients were higher than 0.999. The average recovery was higher than 86% (R.S.D.: 7–11%). The analytical procedure was applied to determination of the booster biocides in port sediment samples from the southwestern Spain. Sea-Nine 211 was found in one sediment at a level of 2.1 ng g−1. Irgarol was present in all the sediments at concentrations between 2 and 9 ng g−1.

Determination of short chain chlorinated paraffins in water by stir bar sorptive extraction–thermal desorption–gas chromatography–triple quadrupole tandem mass spectrometry

A simple, robust, sensitive and environment friendly method for the determination of short chain chlorinated paraffins (SCCPs) in water using stir bar sorptive extraction (SBSE) coupled to thermal desorption–gas chromatography–triple quadrupole tandem mass spectrometry (TD–GC–QqQ-MS/MS) was developed. SBSE was performed using 100mL of water sample, 20mL of methanol as a modifier, and a commercial sorptive stir bar (with 10mm×0.5mm PDMS layer) during extraction period of 16h. After extraction, the sorptive stir bar was thermally desorbed and online analysed by GC–MS/MS. Method performance was evaluated for MilliQ and surface water spiked samples. For both types of matrices, a linear dynamic range of 0.5–3.0μgL−1 with correlation coefficients >0.999 and relative standard deviations (RSDs) of the relative response factors (RRFs) <12% was established. The limits of quantification (LOQs) of 0.06 and 0.08μgL−1, and the precision (repeatability) of 6.4 and 7.7% (RSDs) were achieved for MilliQ and surface water, respectively. The method also showed good robustness, recovery and accuracy. The obtained performance characteristics indicate that the method is suitable for screening and monitoring and compliance checking with environmental quality standards (EQS, set by the EU) for SCCPs in surface waters.

Development of an innovative and “green” stir bar sorptive extraction–thermal desorption–gas chromatography–tandem mass spectrometry method for quantification of polycyclic aromatic hydrocarbons in marine biota

There is a growing awareness of the need to reduce the negative impact of chemical analyses on the environment and to develop new eco-friendly and sustainable analytical methods without compromising performance. In this study, we developed a “green” analytical method enabling the accurate and simultaneous routine analysis of 21 polycyclic aromatic hydrocarbons (PAHs) in reduced quantities (100mg and 1g wet weight (WW)) of marine biota samples (fish muscle, mussel and oyster tissues) using alkaline digestion combined with stir bar sorptive extraction–thermal desorption–gas chromatography–tandem mass spectrometry (SBSE–GC–MS/MS). The innovative method provides good selectivity and specificity for most compounds. In 1gWW samples, limits of quantification (LOQs) ranged from 1 to 10μg/kgWW in fish muscle and from 0.5 to 10μg/kgWW in mussel tissue. The method enables most analytes to be quantified below the restrictive limits established by the European Commission (2 and 10μg/kgWW in fish muscle and bivalve mollusc, respectively). Higher LOQs were obtained in 100mgWW samples ranging from 1 to 50μg/kgWW. Recovery and linearity were assessed for all analytes. The results were satisfactory for most compounds with recoveries ranging from 94% to 117% in 1gWW mussel samples at spike concentration of 10ng/gWW with standard deviation not exceeding 12%. However, results confirmed that the SBSE efficiency is affected by the complexity of biological matrices, especially for high molecular weight compounds in lipid-rich mussel tissue. Because of the matrix effects, matrix-matched calibrations were carried out. Validation was performed using the standard reference material 1974c with recovery ranging from 71% to 119% except for naphthalene, anthracene and benzo(e)pyrene that were therefore not validated. Overall, the developed method meets analytical validation criteria for most compounds. Thanks to the combination of alkaline digestion and SBSE, which greatly simplifies sample treatment and limits solvent use to ethanol, the developed method followed most green analytical chemistry principles.

Development of stir-bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry for the analysis of musks in vegetables and amended soils

The aim of this study was to develop a sensitive and environment-friendly method based on stir-bar sorptive extraction (SBSE) followed by thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) to determine 8 synthetic musks (musk ambrette, musk ketone, celestolide, tonalide, galaxolide, phantolide, traseolide, and cashmeran) in vegetables (lettuce, carrot, and pepper) and amended soil samples. In a first step sorptive extraction was studied both in the headspace (HSSE) and in the immerse mode (SBSE). The best results were obtained in the immersion mode which was further studied. The influence of the main factors: methanol (20%) and NaCl addition (0%), extraction temperature (40°C) and time (180min), extraction solvent volume (9mL) and stirring rate (600rpm) on the efficiency of SBSE was evaluated by means of experimental designs. In the case of TD, desorption time (10min), desorption temperature (300°C), cryo-focusing temperature (−30°C), vent flow (75mL/min) and vent pressure (7.2psi) were studied using both a fractioned factorial design and a central composite design (CCD). The method was validated in terms of apparent recoveries (AR%), method detection limits (MDLs) and precision at two different concentration levels. Although quantification using instrumental calibration rendered odd results in most of the cases, satisfactory recoveries (74–126%) were obtained in the case of matrix-matched calibration approach for all of the analytes and matrices studied at the two concentration levels evaluated. MDLs in the range of 0.01–0.8ng/g and 0.01–1.1ng/g were obtained for vegetables and amended soil samples, respectively. RSD values within 1–23% were obtained for all the analytes and matrices. Finally, the method was applied to the determination of musks in vegetable and amended soil samples.

Determination of selenomethionine and seleno-methyl-selenocysteine in biota by ultrasonic-assisted enzymatic digestion and multi-shot stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

A method based on stir bar sorptive extraction (SBSE) and thermal desorption (TD)–gas chromatography–mass spectrometry (GC–MS) has been optimized for the determination of seleno-methyl-selenocysteine (SeMetSeCys) and selenomethionine (SeMet) in biota samples. Aliquots of freeze-dried tissue, a mixture of protease XIV-lipase and water were sonicated for 2min. After extraction, the extract was separated by centrifugation and subjected to derivatization and SBSE–TD–GC–MS. The parameters affecting derivatization, absorption and desorption steps were investigated. The optimized conditions consist of a derivatization with 40μL of ethyl chloroformate (ECF) in 400μL of a water:ethanol:pyridine (60:32:8) mixture, followed by dilution to 1.5mL of 70g NaClL−1 in water at neutral pH and an extraction step using 10mm×1mm PDMS stir bar, stirring at 800rpm for 20min at room temperature (23±1°C). Three stir bars were used for the extraction of three different aliquots of the same sample and then placed in a single glass desorption liner and simultaneously desorbed for GC–MS analysis. The desorption step required the following conditions: 300°C (desorption temperature), 6min (desorption time), 50mLmin−1 (vent flow) and −5°C (cryotrapping temperature). The method provided precise (8.1%) and accurate results in the mgSekg−1 range (using the selected-ion monitoring-SIM mode) against certified reference material SELM-1 yeast, with recoveries higher than 80% for spiked algae and clams samples.

An Improved Method for Determination of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Sediment by Ultrasonic Solvent Extraction Followed by Stir Bar Sorptive Extraction Coupled to TD–GC–MS

An improved simple, fast and miniaturized method for the determination of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in freshwater sediment using ultrasonic solvent extraction followed by stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry (USE-SBSE/TD–GC–MS) is presented. The sediment sample (0.2 g) is extracted with methanol (1:1.2, 2:1.0 mL) in an ultrasonic bath (two 5-min extraction cycles). The combined extracts are made up to 5 mL with water, and from the resulting solution, the analytes are preconcentrated on a stir bar coated with polydimethylsiloxane during 1 h of stirring. The loaded sorptive stir bar is then thermally desorbed and online analysed by GC–MS. For the analytes in river sediment, a linear dynamic range of 0.5–50 ng g−1 was established and limits of detection in sub nanogram-per-gram level were achieved. Recoveries and repeatability were obtained in the ranges 62.8–91.5 % and 3.6–15.0 %, respectively. The method accuracy was confirmed by the analysis of PCBs and PBDEs in a certified reference material. The main improvement in comparison with similar published methods is in shortening the sample handling time and the method miniaturization.

Determination of five booster biocides in seawater by stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

Stir bar sorptive extraction (SBSE) and thermal desorption (TD)–gas chromatography–mass spectrometry (GC–MS) have been optimized for the determination of five organic booster biocides (Chlorothalonil, Dichlofluanid, Sea-Nine 211, Irgarol 1051 and TCMTB) in seawater samples. The parameters affecting the desorption and absorption steps were investigated using 10mL seawater samples. The optimised conditions consisted of an addition of 0.2gmL−1 KCl to the sample, which was extracted with 10mm length, 0.5mm film thickness stir bars coated with polydimethylsiloxane (PDMS), and stirred at 900rpm for 90min at room temperature (25°C) in a vial. Desorption was carried out at 280°C for 5min under 50mLmin−1 of helium flow in the splitless mode while maintaining a cryotrapping temperature of 20°C in the programmed-temperature vaporization (PTV) injector of the GC–MS system. Finally, the PTV injector was ramped to a temperature of 280°C and the analytes were separated in the GC and detected by MS using the selected-ion monitoring (SIM) mode. The detection limits of booster biocides were found to be in the range of 0.005–0.9μgL−1. The regression coefficients were higher than 0.999 for all analytes. The average recovery was higher than 72% (R.S.D.: 7–15%). All these figures of merit were established running samples in triplicate. This simple, accurate, sensitive and selective analytical method may be used for the determination of trace amounts of booster biocides in water samples from marinas.

Determination of Polycyclic Aromatic Hydrocarbons in Air by Stir Bar Sorptive Extraction-Thermal Desorption-Gas Chromatography Tandem Mass Spectrometry

Determination of Polycyclic Aromatic Hydrocarbons in Air by Stir Bar Sorptive Extraction-Thermal Desorption-Gas Chromatography Tandem Mass Spectrometry

Rapid Determination Method for 12 Pyrethroid Pesticide Residues in Tea by Stir Bar Sorptive Extraction-Thermal Desorption-Gas Chromatography

Abstract The 12 pyrethroid Pesticides residues in tea samples can be rapidly extracted and separated by a noval stir bar sorptive extraction(SBSE)-thermal desorption(TDU)-gas chromatography(GC) method. Impurities and pyrethroid pesticides residues of tea can be seperated by this method.and then use TDU-GC to analyse pyrethroid Pesticides residues. The residues of 12 pyrethroid pesticides at same time can be identified and quantified simultaneously by SBSE-TDU-GC rapidiy with high sensitivity and good reproducibility. This method is simple, rapid, and the average adding standard recovery ratios were 92.89%-105.01%.The correlation coefficient of pyrethroid pesticides in tea samples is >0.9926. Good repeatability(n=6) was obtained in all the cases with The relative standard deviation lower 9.7%.Pyrethroid pesticides residues in 4 real tea samples can be determined rapidly by this method, their pyrethroid pesticide residues are all less than MRL of China and European union.

Determination of Polycyclic Aromatic Hydrocarbons in Air by Stir Bar Sorptive Extraction-Thermal Desorption-Gas Chromatography Tandem Mass Spectrometry

A method was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in indoor air by a novel passive air sampler, polydimethylsiloxane (PDMS)-coated stir bar sorptive extraction (SBSE), which is detected by thermal desorption (TD) coupled to gas chromatography/triple quadrupole mass spectrometry (GC/MS/MS). PAH standard was added to the surface of stir bar, and it would not be put into a desorption tube until solvent was evaporated. The experimental conditions of daughter ions, collision energy under multiple reactions monitoring (MRM) mode were optimized. To enhance detection sensitivity, TD parameters like desorption temperature (300 degrees C), cooled injection system (CIS) temperature (-60 degrees C) and desorption time (6 min) were also optimized. 12 deuterated internal standards were applied to identify and quantify 16 EPA-PAH congeners under 4 functions. The method recovery is 45.1%-109% and the limits of detection (LOD) were in the range of 0.020-0.054 ng. The established method is further applied to analyze 16 PAHs of indoor air before and after coal combustion by hanging stir bars in a room as passive air sampler. The PAHs concentrations of indoor air before and after coal combustion samples were 4.24-5.32 ng and 172-200 ng, respectively

Development of a screening method for the analysis of organic pollutants in water using dual stir bar sorptive extraction-thermal desorption-gas chromatography–mass spectrometry

The development of a method for screening of organic compounds with a wide range of physico-chemical properties in water, based on dual stir bar sorptive extraction coupled with thermal desorption and gas chromatography–mass spectrometry (dual SBSE-TD-GC–MS) is described. The investigated water sample is divided into two aliquots and extracted with stir bar sorptive extraction at two different conditions: using addition of methanol or sodium chloride, respectively. Following extraction, the two stir bars are inserted into the same glass thermal desorption liner and are simultaneously desorbed and analysed by GC–MS. The method optimisation was performed using 45 environmentally harmful substances with different volatilities (boiling point from 193 to 495°C), polarity (logKow from 2.17 to 8.54) and acido-basic properties. The majority of model compounds was selected from the EU list of priority substances in the field of water policy and from the US EPA method 625, respectively. Optimisation was performed for extraction parameters (sample volume, extraction time, stirring rate, addition of modifiers) as well as for the thermal desorption conditions (desorption flow, desorption time, cryofocusing temperature). Performance characteristics (recovery, repeatability, carryover, linearity, limits of detection and quantification) were determined for the optimised method. An example of analysis of a contaminated groundwater sample is presented.

Overall calibration procedure via a statistically based matrix-comprehensive approach in the stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry analysis of pesticide residues in fruit-based soft drinks

Stir bar sorptive extraction (SBSE)–thermal desorption (TD) procedure combined with gas chromatography mass spectrometry (GC–MS) and the statistical variance component model (VCM) is applied to the determination of semi-volatile compounds including organochlorine and organophosphorus pesticides in various synthetic and real fruit-based soft drink matrices. When the matrix effects are corrected using isotopically labelled or non labelled internal standard, but matrix/calibration run-induced deviations are still present in the measurements, the adoption of a variance component model (VCM) in the quantitative analysis of various matrices via an overall calibration curve is successful. The method produces an overall calibration straight line for any analyte accounting for the uncertainty due to all the sources of uncertainty, namely matrix-induced deviations, calibration runs performed at different times, measurement errors. Small increases in the detection limits and in uncertainty in the concentration values obtained in the inverse regression face favourably the decrease in times and costs for routine analyses.

Stir bar sorptive extraction-thermal desorption-gas chromatography–mass spectrometry: An effective tool for determining persistent organic pollutants and nonylphenol in coastal waters in compliance with existing Directives

A multi-residual method based on stir bar sorptive extraction coupled with thermal desorption-gas chromatography–mass spectrometry (SBSE-TD-GC–MS) has been developed to measure 49 organic pollutants (organochlorine pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenyl ethers and nonylphenol) in seawater. Using 100ml of water, the method exhibited good linearity, with recoveries between 86% and 118% and relative standard deviation between 2% and 24% for almost all compounds. The method was applied to determine target contaminants in Catalonian seawater, including coastal areas, ports and desalination plant feed water. Overall individual compound levels oscillated between 0.16 and 597ngl−1; PAHs and nonylpenol were the compounds found at the highest concentrations. The method provided LODs between 0.011 and 2.5ngl−1, lower than the Environmental Quality Standards (EQS) fixed by Directive 2008/105/EC. In compliance with the directive, this method can be used as a tool to survey target compounds and is aimed at protecting coastal ecosystems from chemical pollution.

Evaluation of Automated Stir Bar Sorptive Extraction-Thermal Desorption-Gas Chromatography Electron Capture Negative Ion Mass Spectrometry for the Analysis of PBDEs and PBBs in Sheep and Human Serum

Stir-bar sorptive extraction and automated thermal desorption/cryotrapping interfaced to capillary gas chromatography and electron capture negative ion mass spectrometry is shown to effectively isolate and recover polybrominated diphenyl ethers and polybrominated biphenyls from sheep and human serum. This paper describes the development of the method and demonstrates the feasibility of using Twister with spiked serum. Conditions for conducting stir-bar sorptive extraction and for automated thermal desorption that led to acceptable analyte recoveries were optimized. The approach to sample preparation introduced here significantly reduces tedious labor and solvent consumption associated with conventional liquid-liquid extraction.

Multi-residue off-flavour profiling in wine using stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

A multi-residue method (MRM) for the detection and quantification of eight compounds responsible for off-flavours in wine using stir bar sorptive extraction (SBSE) followed by thermal desorption (TD) and gas chromatography–mass spectrometry (GC–MS) analysis is presented. The extraction and desorption conditions were optimised in order to get the best compromise for the simultaneous analysis of the eight target solutes, belonging to different chemical classes. The analytical conditions enable the quantification of the solutes below their respective organoleptic perception thresholds in wine. The method displayed good linearity over the concentration ranges explored in wine as well as excellent repeatability (RSD below 6%) and good reproducibility (RSD below 24%). The developed methodology was applied to the analysis of several wines and showed good agreement with the results collected with headspace solid-phase microextraction (HS-SPME) or liquid–liquid extraction (LLE) followed by GC–MS or electron capture detection (ECD). Good correlation was also found between the analytical and sensory results.

Simultaneous determination of pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in seawater and interstitial marine water samples, using stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

A method for the simultaneous determination of semi-volatile organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine and organophosphorus pesticides) in marine samples has been developed, for the first time, using the stir bar sorptive extraction technique (SBSE) and thermal desorption coupled to capillary gas chromatography–mass spectrometry (SBSE-TD-GC–MS). Polydimethyl siloxane (PDMS) was used for the extraction of the selected analytes and two procedures have been optimised and validated, one for seawater samples (100 mL) and another for interstitial water samples (10 mL), using PDMS stir bars of 20 mm and 10 mm size, respectively. The extraction and analytical conditions, such as extraction time, matrix effects, sample volume and desorption time, were optimised. The proposed methods are sensitive, simple and show good linearity and detection limits lower than 1 ng L −1 with seawater and lower than 10 ng L −1 with interstitial marine water for the majority of compounds tested. Repeatability and reproducibility, expressed as relative standard deviation, have values lower than 20% for the majority of analytes considered. The recoveries for both sample volume procedures are higher than 60 and 70% for 10 and 100 mL, respectively, except for the more apolar (some PAHs and PCBs) and the more polar (some triazines) analytes which present lower values. The present SBSE/GC/MS method was applied for the analysis of trace organic contaminants in seawater and interstitial water samples from Cadiz Bay (SW of Spain). Terbutylazine, DDX and some PAHs were found at several seawater sampling points at ng L −1 levels, and some PAHs in interstitial water too.

The analysis of estrone and 17β-estradiol by stir bar sorptive extraction–thermal desorption–gas chromatography/mass spectrometry: Application to urine samples after oral administration of conjugated equine estrogens

The development of a sensitive and solvent-free method for the measurement of estrone (E 1) and 17β-estradiol (17β-E 2) in human urine samples is described. The deconjugated estrogens were derivatized in situ with acetic acid anhydride and the derivatives were extracted directly from the aqueous samples using stir bar sorptive extraction (SBSE). The compounds containing a secondary alcohol function are further derivatized by headspace acylation prior to thermal desorption and gas chromatography/mass spectrometry (GC/MS). A number of experimental parameters, including salt addition, temperature and time, were optimized to increase the recovery of E 1 and 17β-E 2 by SBSE. The derivatization reactions were also optimized to obtain the highest yields of the acylated estrogens. Detection limits of 0.02 and 0.03 ng mL −1 were obtained for E 1 and 17β-E 2, respectively. The method was applied to determine the effect of conjugated equine estrogen intake on the excretion of E 1 and 17β-E 2 in human urine samples. Increased levels of the endogenous estrogens were detected after administering a standard dose of Premarin to a female volunteer. Routine monitoring of estrogen levels is recommended to avoid a high urinary excretion of E 1 and 17β-E 2, nowadays enlisted as endocrine disrupting chemicals (EDCs), during hormone replacement therapy.

Analysis of nine polybrominated diphenyl ethers in water samples by means of stir bar sorptive extraction-thermal desorption-gas chromatography–mass spectrometry

An optimised method using stir bar sorptive extraction (SBSE) for the determination of nine bromodiphenil ether (Lake Michigan mix) from water samples was developed. Recoveries near to 100% were found by using 20 mm × 0.5 mm (length × film thickness) PDMS commercial stir bars with 100 mL spiked water samples and 20% methanol addition and an extraction period of 25 h. Method sensitivity, linearity, repeatability and reproducibility have been also studied. Detection limits between 0.4 and 9.4 ng/L were calculated for the combination of SBSE and thermal desorption-GC–MS. The procedure was applied a real sample, a surface water contaminated by the effluents, and the results were compared with a classical liquid–liquid extraction method.