Optimization of stir bar sorptive extraction applied to the determination of pesticides in vinegars

Stir bar sorptive extraction (SBSE) has been evaluated for analysing pesticides in vinegar. The extraction analytical conditions have been optimised using a two-level factorial design expanded further to a central composite design. After optimization, the proposed analytical conditions are: sample volume 40 mL, sampling time 150 min, and stirring speed 1000 rpm. On the basis of the results, it was decided not to add NaCl. The SBSE procedure developed shows detection limits and linear ranges adequate for analysing this type of compound, giving recoveries close to 100%. The repeatability and reproducibility values obtained were lower than 18 and 23%, respectively. The method was applied to a variety of commercial vinegars. SBSE is a very simple, solvent-free, and fast technique with high sensitivities.     

Analysis of 35 priority semivolatile compounds in water by stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry. I. Method optimisation

A multiresidue method for the determination of 35 organic micropollutants (pesticides and polycyclic aromatic hydrocarbons) in water has been optimised using stir bar sorptive extraction (SBSE) and thermal desorption coupled to capillary gas chromatography-mass spectrometry (GC-MS). In the present work, the different parameters affecting the extraction of the analytes from the water samples to the PDMS-coated stir bars and optimisation of conditions affecting thermal desorption are investigated. The optimised conditions consist of a 100-ml water sample with 20% NaCl addition extracted with 20 mm length x 0.5 mm film thickness stir bars at 900 rpm during 14 h at ambient temperature. Desorption is carried out at 280 degrees C during 6 min under a helium flow of 75 ml/min in the splitless mode while maintaining a cryofocusing temperature of 20 degrees C in the programmed-temperature vaporisation (PTV) injector of the GC-MS system. Finally, the PTV injector is ramped to a temperature of 280 degrees C and the analytes are separated in the GC and detected by MS using full scan mode (m/z 60-400). Under the described conditions, the good repeatability, high analyte recoveries and robustness, make SBSE a powerful tool for routine quality control analysis of the selected semivolatile compounds in water samples.     

An experimental design approach to optimise the determination of polycyclic aromatic hydrocarbons from rainfall water using stir bar sorptive extraction and high performance liquid chromatography-fluorescence detection

Stir bar sorptive extraction (SBSE) followed by HPLC-fluorescence detection (FLD) was optimised for analysing 15 polycyclic aromatic hydrocarbons (PAHs) from water samples, especially rainfall water with low PAH content. The literature data described widely different experimental conditions for the extraction of PAHs by SBSE. A chemometric approach was therefore used to evaluate the statistically influential and/or interacting factors, among those described in the literature, and to find the best extraction and desorption conditions. Among six factors studied in a 2(6-2) fractional factorial design, only sample volume, extraction time and the interaction between both of them had significant effects on the PAH extraction recoveries. Optimal sample volume of 10 mL and extraction time of 140 min were obtained with a response surface design. For the desorption conditions, a Box-Behnken design showed that desorption time, temperature and PAH concentrations had significant effects. The best conditions were two successive desorptions with 100 microL of acetonitrile for 25 min at 50 degrees C. The optimised method was repeatable (RSD< or =5.3% for 50 ng L(-1) spiked water and < or =12.8% for 5 ng L(-1) spiked water), linear (R(2)> or =0.9956), with quantitative absolute recoveries (> or =87.8% for 50 ng L(-1) spiked water), and with the LOD between 0.2 and 1.5 ng L(-1). The optimised method was successfully applied to six-rainfall water samples collected in a suburban area. The total PAHs concentrations studied ranged from 31 to 105.1 ng L(-1). Seasonal variation was observed and on average three PAHs were at the highest concentrations (phenanthrene, fluoranthene and pyrene).     

Development of a method for the determination of UV filters in water samples using stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry

Stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) was applied for the determination of 9 UV filters in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 20 mL of water sample at pH 2 (10% MeOH) and stirred at 1000 rpm for 180 min. Then, the stir bar was subjected to TD-GC-MS. The desorption conditions (desorption temperature and desorption time) and SBSE parameters (ionic strength, pH, presence of organic solvent and time) were optimised using a full factorial design and a Box-Behnken design, respectively. The method shows good linearity (correlation coefficients >0.994) and reproducibility (RSD<16%). The extraction efficiencies were above 63% for all the compounds. Detection limits were between 0.2 and 63 ng/L. The developed method offers the ability to detect several UV filters at ultra-low concentration levels with only 20 mL of sample volume. The effectiveness of the method was tested by analysing real samples such as lake water, river water and treated wastewater. The application of the method allowed reporting the levels of UV filters in environmental water samples.     

Development of a stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry method for the simultaneous determination of several persistent organic pollutants in water samples

Stir bar sorptive extraction (SBSE) and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE-TD-GC-MS) was applied to the simultaneous determination of ultra-traces of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs), 6 phthalate esters (PEs) and 3 nonylphenols (NPs) in water samples. The parameters that could affect the sorption-desorption efficiency were studied. A Plackett-Burman design was used for the screening of the main effects of the experimental parameters related to the desorption step (desorption time, desorption temperature, desorption flow, cryo-focusing temperature and vent pressure). Afterwards, two central composite designs were used to find the optimal process settings for the extraction and desorption steps. The best analytical compromise conditions for the simultaneous determination of analytes from spiked water samples were found to be: sample volume (20 mL), sodium chloride addition (30%), methanol addition (20%), desorption time (10 min), desorption temperature (300 degrees C), desorption flow (23 mL min(-1)), cryo-focusing temperature (-50 degrees C) and vent pressure (7 psi). Remarkable recovery, repeatability and reproducibility were attained. Furthermore, excellent linearities (r(2) = 0.959-0.999) and low detection limits (0.1-10 ng L(-1)) were also achieved for the congeners studied. The proposed methodology was applied for the simultaneous determination of PAHs, PCBs, PEs and NPs in sea and estuarine waters. The influence of humic acids on the recovery was also studied.     

应用搅拌棒吸附萃取-热脱附-气相色谱-质谱分析烟用香料的化学成分

应用搅拌棒吸附萃取法(SBSE)提取烟用香料的化学成分,并利用热脱附(TD)和色谱-质谱联用(GC-MS)进行分析。对影响萃取效果的因素(萃取时间和氯化钠的加入量)进行了考察,并采用正交试验法对影响热脱附的3个主要因素(脱附温度、脱附时间和冷阱温度)进行了优化,得到了较优的实验条件。对方法的重现性进行了考察,同一样品6次测定所得30个组分的峰面积的相对标准偏差（RSD）平均值小于10%,说明所建立方法的重现性较好。在样品中鉴别出酯类、酮类和醛类等30种不同化学组分,这些物质反映了该香料的香气特点。实验证明SBSE和TD适用于烟用香料的快速分析测定。     

聚酰亚胺固相萃取搅拌棒的制备及其在环境水中酚类的分析应用

利用相转换法制备了聚酰亚胺吸附萃取搅拌棒,用5种有机酚作为评价标样,并与现有商品化吸附萃取搅拌棒进行比较。优化了萃取搅拌速度、溶液离子强度、萃取温度、萃取时间以及热解析温度和时间。在最佳实验条件下,100 mL 样品,30% NaCl,在25℃下,经活化5 min 后的聚酰亚胺吸附搅拌棒萃取30 min (800 r/ min),然后300℃热解析4 min,使目标物脱附,再进行色谱分析。目标物在大于两个数量级浓度范围内具有良好的线性(R≥0.9995),定量限(LOQ,S/ N=10)为0.028~0.123μg/ L,重复性为1.6%~9.7%。将SBSE 与气相色谱-质谱联用,对海水、自来水和污水中的酚类进行定性与定量分析,结果表明,聚酰亚胺吸附萃取搅拌棒具有良好的选择性,最高热解析温度350℃,在分析水中痕量极性化合物领域具有广阔应用前景。     

Stir bar sorptive extraction and trace analysis of alkylphenols in water samples by thermal desorption with in tube silylation and gas chromatography-mass spectrometry

A novel method called thermal desorption (TD) with in tube silylation followed by gas chromatography-mass spectrometry (GC-MS), which is used for the determination of trace amounts of alkylphenols (APs) in river water samples, is described. APs are extracted from river water samples and concentrated by the stir bar sorptive extraction (SBSE) technique. The stir bar coated with polydimethylsiloxane (PDMS) is added to 2.0 ml water sample and stirring is carried out for 60 min at room temperature (25 degrees C) in the vial. Then, the PDMS stir bar is subjected to TD with in tube silylation followed by GC-MS. The detection limit is of the sub pg ml(-1) (ppt) level. The method shows good linearity and the correlation coefficients are higher than 0.99 for all analytes. The average recoveries of APs are higher than 90% (R.S.D.: 3.6-14.8%, n=6). This simple and sensitive analytical method may be used in the determination of trace amounts of APs in river water samples.     

Review of SBSE Technique for the Analysis of Pesticide Residues in Fruits and Vegetables

Stir bar sorptive extraction (SBSE) is a microextraction technique, introduced to overcome the problem of limited extraction capacity and fragile fiber coatings inherent in the solid phase microextraction technique. The major limitations of the SBSE technique are that only polydimethylsiloxane has been commercially available, this reduces its use to non-polar analytes, and its tedious reconstitution step which can lead to loss of analytes and introduction of impurities. The current trend has been aimed at the use of other materials, some of which are commercially available, such as restricted access materials, carbon adsorbents, molecularly imprinted polymers, ionic liquids, microporous monoliths, sol–gel prepared coatings and dual phase material. This has greatly helped in widening the applications of SBSE for pesticide analysis in fruits and vegetables and other matrices. The introduction of a thermal desorption unit which eliminates the reconstitution step of the stir bar in organic solvents before instrumental analysis has helped to automate the extraction method online with gas chromatography. This paper reviews the use of SBSE in pesticide residues analysis in fruits and vegetables, with a view on sample preparation steps, method optimization and validation of analytical figures of merit.     

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.     

Microwave-assisted extraction followed by gas chromatography-mass spectrometry for the determination of endocrine disrupting chemicals in river sediments

A method for the simultaneous measurement of trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butyl-phenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) analysis. The conditions for derivatization with acetic acid anhydride were investigated. A polydimethylsiloxane (PDMS)-coated stir bar and derivatization reagents were added to 10 ml of water sample and stirring was commenced for 10-180 min at room temperature (25 degrees C) in a headspace vial. Then, the extract was analyzed by TD-GC-MS. The optimum time for SBSE with in situ derivatization was 90 min. The detection limits of 2,4-DCP, BP, OP, NP, PCP and BPA were 2, 1, 0.5, 5, 2 and 2 pg ml(-1), respectively. The method showed good linearity over the concentration ranges of 10, 5, 2, 20, 10 and 10-1000 pg ml(-1) for 2,4-DCP, BP, OP, NP, PCP and BPA, respectively, and the correlation coefficients were higher than 0.99. The average recoveries of those compounds in river water samples were equal to or higher than 93.9% (R.S.D. <7.2%) with correction using the added surrogate standards. This simple, accurate, sensitive and selective method can be used in the determination of trace amounts of phenolic xenoestrogens in river water samples.     

Use of experimental design in the optimisation of stir bar sorptive extraction followed by thermal desorption for the determination of brominated flame retardants in water samples

A method for the determination of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in water samples is proposed. The method involving stir bar sorptive extraction (SBSE) and thermal desorption followed by gas chromatography coupled with mass spectrometry was optimised using statistical design of experiments. In the first place, the influence of different polydimethylsiloxane stir bars was studied. A Plackett–Burman design was chosen to estimate the influence of five factors on the efficiency of the SBSE process: desorption time (5–10 min), desorption temperature (250–300 °C), desorption flow (50–100 mL min⁻¹), cryofocusing temperature (-130 to 40 °C) and vent pressure (0–12.8 psi). Afterwards, two central composite designs were used to find the optimal process settings that were applied to the optimisation of both desorption and extraction efficiency. In the case of the desorption parameters, long desorption times (10 min) and desorption flows lower than 70 mL min^-1 yielded the best signals for the majority of compounds. However, different behaviour among the analytes was observed for the vent pressure and we decided to fix it at an intermediate value (7 psi). In the case of extraction parameters, the sample volume and the addition of NaCl did not have a significant effect, while the addition of methanol yielded better extraction responses. Remarkable recovery (82–106%) and repeatability (less than 18%) were attained. Furthermore, excellent regression coefficients (r ² = 0.991–0.999) and low detection limits (1.1–6.0 ng L⁻¹) were also achieved for the congeners studied. The proposed method was applied to the analyses of PBDEs and PBBs in waters from the Basque Country, Spain.     

Stir bar sorptive extraction and high-performance liquid chromatography-fluorescence detection for the determination of polycyclic aromatic hydrocarbons in Mate teas

A simple procedure based on stir bar sorptive extraction (SBSE) and high-performance liquid chromatography-fluorescence detection (HPLC-FLD) is presented for the determination of 15 polycyclic aromatic hydrocarbons (PAHs) in herbal tea prepared with Mate leaves (Ilex paraguariensis St. Hil.). The influence of methanol and salt addition to the samples, the extraction time, the desorption time and the number of desorption steps, as well as the matrix effect, were investigated. Once the SBSE method was optimised (10 mL of Mate tea, 2h extraction at room temperature followed by 15 min desorption in 160 microL of an acetonitrile (ACN)-water mixture), analytical parameters such as repeatability (< or = 10.1%), linearity (r2 > or = 0.996), limit of detection (LOD, 0.1-8.9 ng L(-1) ), limit of quantitation (LOQ, 0.3-29.7 ng L(-1) and absolute recovery (24.2-87.0%) were determined. For calibration purposes, a reference sample was firstly obtained by removing the analytes originally present in the lowest contaminated Mate tea studied (via SBSE procedure) and then spiked at 1-1200 ng L(-1)range. The proposed methodology proved to be very convenient and effective, and was successfully applied to the analysis of 11 Mate tea samples commercialised in Brazil. The results of the commercial Mate tea samples found by the SBSE approach were compared with those obtained by liquid-liquid extraction (LLE), showing good agreement.     

Stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry for trace analysis of triclosan in water sample

A simple and highly sensitive method called stir bar sorptive extraction (SBSE) and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS), which is used for the determination of trace amounts of 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan) in river water samples, is described. A stir bar coated with polydimethylsiloxane (PDMS) is added to a 10mL water sample and stirring is carried out for 120min at room temperature (25 degrees C) in a vial. Then, the PDMS stir bar is subjected to TD-GC-MS. The detection limit of triclosan is 5ngL(-1) (ppt). The method shows linearity over the calibration range (0.02-20mugL(-1)) and the correlation coefficient is higher than 0.997 for triclosan standard solution. The recovery of triclosan in river water samples ranges from 91.9 to 108.3% (RSD: 4.0-7.0%). This simple, accurate, sensitive, and selective analytical method may be used in the determination of trace amounts of triclosan in river water samples.     

Comparison of stir bar sorptive extraction and membrane-assisted solvent extraction for the ultra-performance liquid chromatographic determination of oxazole fungicide residues in wines and juices

The present study compares two new sample preparation methods, stir bar sorptive extraction (SBSE) and membrane-assisted solvent extraction (MASE) coupled to the novel technique of ultra-performance liquid chromatography (UPLC) for the sensitive, selective and solvent-free determination of six oxazole fungicide residues (hymexazol, drazoxolon, vinclozolin, chlozolinate, oxadixyl and famoxadone) in wine and juices. The analytes were separated on a rapid resolution C(18) column (50 mm x 4.6 mm, I.D., 1.8 microm) thermostated at 50 degrees C with isocratic elution using a 50/50 (v/v) water/acetonitrile (ACN) mobile phase at a flow-rate of 1 mL min(-1) and detected by diode-array detection (DAD). The UPLC method rapidly separates the fungicides (7 min). The best results as regards sensitivity, repeatability and analyte recovery were obtained using SBSE with a polydimethylsiloxane (PDMS) twister, at 60 degrees C for 30 min with stirring at 1700 rpm in the presence of a 0.1M acetate/acetic acid buffer (pH 5) and 20% (m/v) sodium chloride. Liquid desorption was performed with 100 microL of a 80/20 (v/v) ACN/water solution in a desorption time of 15 min. With the PDMS polymer, an apolar phase, hymexazol and oxadixyl were not extracted. Consequently, the SBSE procedure can only be applied to the other four fungicides. Detection limits ranged from 0.05 to 2.5 microgL(-1) at a signal to noise ratio of 3, depending on the compound. Recoveries obtained for spiked samples were satisfactory (83-113%) for all compounds. The proposed method was successfully applied to the analysis of different samples, residues of chlozolinate and drazoxolon being found in samples of red wine and grape juice, respectively.     

Determination of 4-nonylphenol and 4-tert.-octylphenol in water samples by stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry

A simple and highly sensitive method called thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS), which is used for the determination of trace amounts of 4-nonylphenol (NP) and 4-tert.-octylphenol (OP) in water samples, is described. NP and OP in samples are extracted from water samples and concentrated by the stir bar sorptive extraction (SBSE) technique. A stir bar coated with polydimethylsiloxane (PDMS) is added to a 2.0 ml water sample and stirring is carried out for 60 min at room temperature (25 °C) in a headspace vial. Then the extract is high sensitively analyzed by TD-GC-MS without any derivatization step. The optimum SBSE conditions are realized at an extraction time of 60 min. The detection limits are 0.02 ng ml⁻¹ for NP and 0.002 ng ml⁻¹ for OP. The method shows good linearity over the concentration range of 0.1-10 ng ml⁻¹ for NP and 0.01-10 ng ml⁻¹ for OP, and the correlation coefficients are higher than 0.999. The average recoveries of NP and OP are higher than 97% (R.S.D.: 3.6-6.2%) with correction using the added surrogate standards, 4-(1-methyl) octylphenol-d₅ and deuterium 4-tert.-octylphenol. This simple, accurate, sensitive and selective analytical method may be used in the determination of trace amounts of NP and OP in tap and river water samples.     

整体式吸附萃取搅拌棒在检测环境水样中镉离子含量方面的应用

通过逐步聚合反应制备了一种新型整体式吸附萃取搅拌棒,将其应用于环境水中镉离子的吸附萃取.考察了介质酸度、搅拌速率、吸咐时间、解吸溶剂和时间等实验条件对吸附量的影响.控制溶液pH为6.0,搅拌棒转速为300 r/min,吸附30 min,5% HNO3作为解吸液解吸10 min,采用等离子体原子发射光谱仪对Cd离子进行检...     

Sequential stir bar sorptive extraction for uniform enrichment of trace amounts of organic pollutants in water samples

A novel extraction procedure for stir bar sorptive extraction (SBSE) termed sequential SBSE was developed. Compared to conventional SBSE, sequential SBSE provides more uniform enrichment over the entire polarity/volatility range for organic pollutants at ultra-trace levels in water. Sequential SBSE consists of a SBSE performed sequentially on a 5-mL sample first without modifier using one stir bar, then on the same sample after addition of 30% NaCl using a second stir bar. The first extraction with unmodified sample is mainly targeting solutes with high Kow (logKow>4.0), the second extraction with modified sample solution (containing 30% NaCl) is targeting solutes with low and medium Kow (logKow<4.0). After extraction the two stir bars are placed in a single glass desorption liner and are simultaneously desorbed. The desorbed compounds were analyzed by thermal desorption and gas chromatography-mass spectrometry (TD-GC-MS). Recovery of model compounds consisting of 80 pesticides (organochlorine, carbamate, organophosphorus, pyrethroid, and others) for sequential SBSE was evaluated as a function of logKow (1.70-8.35). The recovery using sequential SBSE was compared with those of conventional SBSE with or without salt addition (30% NaCl). The sequential approach provided very good recovery in the range of 82-113% for most of the solutes, and recovery less than 80% for only five solutes with low Kow (logKow<2.5), while conventional approaches (with or without salt addition) showed less than 80% recovery for 23 and 41 solutes, respectively. The method showed good linearity (r2>0.9900) and high sensitivity (limit of detection: <10ngL(-1)) for most of the model compounds even with the scan mode in the MS. The method was successfully applied to screening of pesticides at ngL(-1) level in river water samples.     

ICE Concentration Linked with Extractive Stirrer (ICECLES)

Trace and ultra-trace analysis can be difficult to achieve, especially for polar, more volatile, and/or thermally unstable analytes. A novel technique, coined ICE Concentration Linked with Extractive Stirrer (ICECLES), may help address this problem. The implementation of ICECLES described here combines stir bar sorptive extraction (SBSE) with freeze concentration (FC), where an aqueous solution is frozen during SBSE in order to concentrate analytes into a polydimethylsiloxane (PDMS) coated stir bar. Five test probe molecules with a range of log K_ows (2-butanol, benzyl alcohol, benzaldehyde, dimethyl trisulfide and bromobenzene) were prepared from aqueous solutions using ICECLES. Thermal desorption gas–chromatography mass–spectrometry was then used to quantify these analytes. Parameters affecting the performance of ICECLES (e.g., freeze rate) were evaluated, with extraction at lower speeds resulting in higher extraction efficiencies, whereas the freeze rate and initial analyte concentration only had a minor effect. ICECLES produced much higher extraction efficiencies than SBSE alone, with signal enhancements of up to 474× SBSE. ICECLES also provided excellent reproducibility and lower LODs than SBSE for all compounds tested. ICECLES performed well when used to analyze multiple triazine pesticides and breakdown products in environmental surface waters. Overall, the ICECLES technique was excellent at preparing aqueous samples for trace analysis and shows promise as a novel analytical sample preparation technology.     

An alternative method for analysis of food taints using stir bar sorptive extraction

The determination of taints in food products currently can involve the use of several sample extraction techniques, including direct headspace (DHS), steam distillation extraction (SDE) and more recently solid phase microextraction (SPME). Each of these techniques has disadvantages, such as the use of large volumes of solvents (SDE), or limitations in sensitivity (DHS), or have only been applied to date for determination of individual or specific groups of tainting compounds (SPME). The use of stir bar sorptive extraction (SBSE) has been evaluated as a quantitative screening method for unknown tainting compounds in foods. A range of commonly investigated problem compounds, with a range of physical and chemical properties, were examined. The method was optimised to give the best response for the majority of compounds and the performance was evaluated by examining the accuracy, precision, linearity, limits of detection and quantitation and uncertainties for each analyte.For most compounds SBSE gave the lowest limits of detection compared to steam distillation extraction or direct headspace analysis and in general was better than these established techniques. However, for methyl methacrylate and hexanal no response was observed following stir bar extraction under the optimised conditions.The assays were carried out using a single quadrupole GC-MS in scan mode. A comparison of acquisition modes and instrumentation was performed using standards to illustrate the increase in sensitivity possible using more targeted ion monitoring or a more sensitive high resolution mass spectrometer. This comparison illustrated the usefulness of this approach as an alternative to specialised glassware or expensive instrumentation. SBSE in particular offers a ‘greener’ extraction method by a large reduction in the use of organic solvents and also minimises the potential for contamination from external laboratory sources, which is of particular concern for taint analysis.