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Brain metabolomics is an emerging field that complements the more traditional approaches of neuroscience. However, typical brain metabolomics workflows require that animals be sacrificed and tend to involve tedious sample preparation steps. Microdialysis, the standard technique to study brain metabolites in vivo, is encumbered by significant limitations in the analysis of hydrophobic metabolites, which are prone to adsorption losses on microdialysis equipment. An alternative sampling method suitable for in vivo brain studies is solid-phase microextraction (SPME). In SPME, a small probe coated with a biocompatible polymer is employed to extract/enrich analytes from biological matrices. In this work, we report the use of SPME and liquid chromatography-mass spectrometry for untargeted in vivo analysis of rodent's brains after deep brain stimulation (DBS). First, metabolite changes occurring in brain hippocampi after application of 3 h of DBS to the animals' prefrontal cortex were monitored with the proposed approach. As SPME allows for nonlethal sampling, the same group of animals was sampled again after 8 days of daily DBS therapy. After acute DBS, we detected changes in a broad range of metabolites, including the amino acid citrulline, which may reflect changes in nitric oxide production, as well as various phospho- and glycosphingolipids. Measurements conducted after chronic DBS showed a decrease in hippocampal corticosterone, indicating that DBS may have a regulatory effect in the hypothalamic-pituitary-adrenal axis. Our findings demonstrate the potential of in vivo SPME as a tool of scientific and clinical interest capable of revealing changes in a wide range of metabolites in brain tissue.

This work presents an evaluation of solid-phase microextraction (SPME) SPME in combination with liquid chromatography-high resolution mass spectrometry (LC-HRMS) as an analytical approach for untargeted brain analysis. The study included a characterization of the metabolite coverage provided by C18, mixed-mode (MM, with benzene sulfonic acid and C18 functionalities), and hydrophilic lipophilic balanced (HLB) particles as sorbents in SPME coatings after extraction from cow brain homogenate at static conditions. The effects of desorption solvent, extraction time, and chromatographic modes on the metabolite features detected were investigated. Method precision and absolute matrix effects were also assessed. Among the main findings of this work, it was observed that all three tested coating chemistries were able to provide comparable brain tissue information. HLB provided higher responses for polar metabolites; however, as these fibers were prepared in-house, higher inter-fiber relative standard deviations were also observed. C18 and HLB coatings offered similar responses with respect to lipid-related features, whereas MM and C18 provided the best results in terms of method precision. Our results also showed that the use of methanol is essential for effective desorption of non-polar metabolites. Using a reversed-phase chromatographic method, an average of 800 and 1200 brain metabolite features detected in positive and negative modes, respectively, met inter-fibre RSD values below 30% (n=4) after removal of fibre and solvent artefacts from the associated datasets. For features detected using a lipidomics method, a total of 900 and 1800 features detected using C18 fibers in positive and negative mode, respectively, met the same criteria. In terms of absolute matrix effects, the majority of the model metabolites tested showed values between 80 and 120%, which are within the acceptable range. Overall, the findings of this work lay the foundation for further optimization of parameters for SPME-LC-HRMS methods suitable for in vivo and ex vivo brain (and other tissue) untargeted studies, and support the applicability of this approach for non-destructive tissue metabolomics.

Use of solid phase microextraction (SPME) for cell culture metabolomic analysis allows for the attainment of more sophisticated data from in vitro cell cultures. Moreover, considering that SPME allows the implementation of multiple extractions from the same sample due to its non/low-depletive nature, time course studies using the same set of samples are thus facilitated via this method. Such an approach results in a reduction in the number of samples needed for analysis thus eliminates inter-batch variability related to biological variation occurring during cell culturing. The current work aims to demonstrate the capability of SPME for measurements of combretastatin A4 (CA4) effectiveness on non-small cell cancer cell line. A cultivation protocol was established in the 96-well plate, and a fiber format of SPME was selected for metabolite extraction. The extracellular metabolic pattern of cells was changed after administration of the tested drug. This suggests pharmacological activity of the administered compound towards the studied cell line model. Results support that the use of direct immersion SPME for analysis of cell cultures does not affect cells growth or contaminate sample. Consequently, SPME allows the attainment of accurate information regarding drug uptake, metabolism, and metabolomic changes in the studied cells induced by exposure to the drug simultaneously in a single experiment.

Recently the connection between oxidative stress and various diseases, including cancer and Alzheimer's, attracts notice as a pathway suitable for diagnostic purposes. 8-Oxo-deoxyguanosine and 8-oxo-deoxyadenosine produced from the interaction of reactive oxygen species with DNA become prominent as biomarkers. Several methods have been developed for their determination in biofluids, including solid-phase extraction and enzyme-linked immunosorbent assays. However, still, there is a need for reliable and fast analytical methods. In this context, solid-phase microextraction offers many advantages such as flexibility in geometry and applicable sample volume, as well as high adaptability to high-throughput sampling. In this study, a solid-phase microextraction method was developed for the determination of 8-oxo-deoxyguanosine and 8-oxo-deoxyadenosine in biofluids. The extractive phase of solid-phase microextraction consisted of hydrophilic-lipophilic balanced polymeric particles. In order to develop a solid-phase microextraction method suitable for the determination of the analytes in saliva and urine, several parameters, including desorption solvent, desorption time, sample pH, and ionic strength, were scrutinized. Analytical figures of merit indicated that the developed method provides reasonable interday and intraday precisions (

Solid phase microextraction (SPME) is a versatile, non-exhaustive sample preparation tool that has been demonstrated to be well-suited for facile and effective analysis of a broad range of compounds in a plethora of studies. A growing number of reports describing diverse SPME workflows for novel investigations in a variety of fields, such as flavor and fragrance investigations, environmental studies, and diverse bioanalytical applications, among others, corroborate the applicability of this microextraction tool in the analytical sciences

This study demonstrates the quantitative capabilities of coated blade spray (CBS) mass spectrometry (MS) for the concomitant analysis of multiple target substances in biofluid spots. In CBS-MS the analytes present in a given sample are first isolated and enriched in the thin coating of the CBS device. After a quick rinsing of the blade surface, as to remove remaining matrix, the analytes are quickly desorbed with the help of a solvent and then directly electrosprayed into the MS analyzer. Diverse pain management drugs, controlled substances, and therapeutic medications were successfully determined using only 10 µL of biofluid, with limits of quantitation in the low/sub ng·mL−1 level attained within 7 minutes.

The widespread use of pharmaceuticals in both human and animal populations, and the resultant contamination of surface waters from the outflow of water treatment facilities is an issue of growing concern. This has raised the need for analytical methods that can both perform rapid sample analysis and overcome the limitations of conventional analysis procedures, such as multistep workflows and tedious procedures. Coated blade spray (CBS) is a solid-phase microextraction based technique that enables the direct-to-mass-spectrometry analysis of extracted compounds via the use of limited organic solvent to desorb analytes and perform electrospray ionization. This paper documents how CBS can be applied for the concomitant tandem mass spectrometric (MS/MS) analysis of nine pharmaceuticals in treated wastewater. The total analysis times of less than 11 min provided limits of detection lower than 50 ng L–1 for all target compounds in river water. The CBS methodology was then compared to a conventional solid-phase e...

Voriconazole is a triazole broad-spectrum antifungal medication often used to treat fungal infections caused by Aspergillus and Fusarium species. One of the main challenges associated with the implementation of this medication is its narrow therapeutic concentration range, demonstrating toxicity at concentrations above 6μg/mL and limited efficacy at concentrations below 2μg/mL. As a result, methodologies which permit the rapid and accurate quantitation of voriconazole in patients are highly desirable. In this work two different approaches based on coated blade spray directly coupled to mass spectrometry (CBS-MS) are introduced; each enabling the quantitation of voriconazole in plasma samples with a simple and fast sample preparation and no chromatographic step. The first approach involves a rapid extraction (1min) of the target analyte from 300μL of human plasma using conventional laboratory vessels (e.g. vial, 96-well plate). Alternatively, the second strategy consists of a 2min extraction from a plasma droplet (10μL) placed on the coated area of the blade. Both procedures were successfully validated and good linearity (R2≥0.998), accuracy (91-122%) and precision (

In this work, a new generation of solid-phase microextraction (SPME) coatings based on polytetrafluoroethylene amorphous fluoroplastics (PTFE AF 2400) as a particle binder is presented. The developed coating was tested for thermal and solvent-assisted desorption, demonstrating its compatibility with both gas- and liquid-chromatographic platforms. The incorporation of hydrophilic-lipophilic balance (HLB) adsorptive particles provided optimal extraction coverage for analytes bearing a broad range of hydrophobicities and molecular weights and of varied chemical diversity. The performance of the newly developed coating was compared to already established coatings based on different polymers such as divinylbenzene/carboxen/polydimethylsiloxane (DVB/Car/PDMS) and octadecyl/benzenesulfonic acid/polyacrylonitrile (C18/SCX/PAN) in order to assess the new prototype versus the existing technology. As this is the first documented instance of PTFE AF being used as a particle immobilizer for SPME, an assessment of the analyte uptake rate and extraction capability of the developed coating was carried out in comparison to other conventionally used polymers. Moreover, the new SPME probes were used to validate an analytical method for determination of banned doping substances, achieving limits of quantitation below the minimum required performance limits (MRPLs) set by the World Anti-Doping Agency (WADA) for most compounds. Considering the broad coverage of the coating in terms of analytes extracted and its suitability for both thermal- and solvent-assisted desorption, these new SPME probes will properly suit various metabolomics applications that involve the use of both gas- and liquid-chromatography.

We introduce a method to couple solid-phase microextraction (SPME) with HPLC-MS using digital microfluidics (DMF). In the new system, SPME fibers are used to extract analytes from complex sample solutions, after which the analytes are desorbed into solvent droplets in a DMF device. The open geometry of DMF allows straightforward insertion of SPME fibers without requiring a complicated interface, and automated droplet manipulation enables multiplexed processing of the fibers. In contrast to other multiplexed SPME elution interfaces, the low volumes inherent to DMF allow for pre-concentration of analytes prior to analysis. The new SPME-DMF-HPLC-MS method was applied to the quantification of pg/mL-level free steroid hormones in urine. We propose that this new method will be useful for a wide range of applications requiring cleanup and pre-concentration with convenient coupling to high-performance analytical techniques.

Fluorinated benzoic acids (FBAs) are frequently used as tracers by the oil industry to characterize petroleum reservoirs. The demand for fast, reliable, robust, and sensitive approaches to separate and quantify FBAs in produced water, both in laboratory and field conditions, has not been yet fully satisfied. In this study, for the first time, thin film solid phase microextraction (TF-SPME) is proposed as a versatile sample preparation tool for the determination of FBAs in produced water by pursing two different approaches. First, an automated high throughput TF-SPME method using solvent desorption for fast and simultaneous preparation of multiple samples prior to liquid chromatographic separation and high resolution mass spectrometric detection (LC-MS) of FBAs was demonstrated for routine laboratory analysis. This method was optimized in terms of extraction phase chemistry, sample pH and ionic strength, extraction/desorption times using two representative FBAs (4-FBA and 2,3,4,5-tetra FBA). It incorporates a relatively simple sample pretreatment involving pH adjustment prior to the TF-SPME, and obtained limits of quantification (LOQ) are at the 1.0 ng mL(-1) level. Second, the applicability of TF-SPME for fast mass spectrometric (MS) determination of FBAs with omission of derivatization and gas chromatographic (GC) separation was proven. This second method consists of manual extractions of analytes from seawater samples with a thermally stable TF-SPME membrane and direct thermal desorption of the extracted FBAs to a MS via a thermal desorption unit (TDU). It was demonstrated that the TF-SPME extracts and thermally releases analytes quantitatively and with good reproducibility. This approach opens up the possibility for on-site measurements with portable analyzers.

Part III of this review focuses on the state of the art of solid-phase microextraction (SPME) applied to bioanalytical and clinical analysis. We describe and discuss recent applications and new advances in terms of extraction phases and SPME configurations. Biocompatible coatings for the direct extraction of different analytes from urine, blood and tissues are perhaps the most promising approach in SPME. We present a review of the different calibration strategies commonly employed, and a discussion on the advantages and the disadvantages of SPME related to the analysis of these biological matrices.

In chemical analysis, sample preparation is frequently considered the bottleneck of the entire analytical method. The success of the final method strongly depends on understanding the entire process of analysis of a particular type of analyte in a sample, namely: the physicochemical properties of the analytes (solubility, volatility, polarity etc.), the environmental conditions, and the matrix components of the sample. Various sample preparation strategies have been developed based on exhaustive or non-exhaustive extraction of analytes from matrices. Undoubtedly, amongst all sample preparation approaches, liquid extraction, including liquid-liquid (LLE) and solid phase extraction (SPE), are the most well-known, widely used, and commonly accepted methods by many international organizations and accredited laboratories. Both methods are well documented and there are many well defined procedures, which make them, at first sight, the methods of choice. However, many challenging tasks, such as complex matrix applications, on-site and in vivo applications, and determination of matrix-bound and free concentrations of analytes, are not easily attainable with these classical approaches for sample preparation. In the last two decades, the introduction of solid phase microextraction (SPME) has brought significant progress in the sample preparation area by facilitating on-site and in vivo applications, time weighted average (TWA) and instantaneous concentration determinations. Recently introduced matrix compatible coatings for SPME facilitate direct extraction from complex matrices and fill the gap in direct sampling from challenging matrices. Following introduction of SPME, numerous other microextraction approaches evolved to address limitations of the above mentioned techniques. There is not a single method that can be considered as a universal solution for sample preparation. This review aims to show the main advantages and limitations of the above mentioned sample preparation approaches and the applicability and capability of each technique for challenging cases such as complex matrices, on-site applications and automation.

The decision to use sample preservation is dependent on knowing the stability of the analytes to be measured in the subsequent analysis. Knowing what causes the instability of the analyte is important (e.g., reaction with matrix components, oxygen or light) as it determines the sample preservation technique to be used. This will ensure the stability of the analyte from sampling to analysis can be undertaken. The sample preservation procedure to be used needs to be documented in the sampling protocol together with training to ensure that it works correctly.

On-site sample preparation is an analytical approach based on direct sampling from the system under investigation. It has the advantage of combining sampling and sample preparation into a single step, thus generally is fast, minimizes the potential sources of error and eliminates the risks for analytes instability. For such analysis solid phase microextraction in thin film geometry (TF-SPME) can provide robust and convenient in vivo sampling, offering in the same time faster analysis and higher extraction recovery (i.e., better sensitivity) due to large surface to volume ratio. In this study, TF-SPME in coated blade and membrane formats with a single extraction phase were used for in vivo and ex vivo saliva extraction and separation by LC and GC, respectively. Due to applicability for wide range of polarity of analytes as well as thermal and solvent stability during the desorption, hydrophilic lipophilic balanced particles (HLB) were chosen as extraction phase and used for fast (5 min) in vivo and ex vivo sampling. The results of metabolomic profiling of the saliva are indicating that even 5 min in vivo sampling using TF-SPME followed by GC and LC analyses provides complementary coverage of wide range of analytes with different physical and chemical properties. To demonstrate the applicability of the method for doping analyses, the SPME-LC-MS/MS method was validated for simultaneous quantification of 49 prohibited substances with limit of quantification (LOQ) ranging between 0.004 and 0.98 ng mL(-1). Moreover, the method was also validated and successfully applied for determination of endogenous steroids in saliva where the concentrations of the analytes are substantially low. The developed assay offers fast and reliable multiresidue analysis of saliva as an attractive alternative to the standard analysis methods.

Most contemporary methods of screening and quantitating controlled substances and therapeutic drugs in biofluids typically require laborious, time-consuming, and expensive analytical workflows. In recent years, our group has worked toward developing microextraction (μe)-mass spectrometry (MS) technologies that merge all of the tedious steps of the classical methods into a simple, efficient, and low-cost methodology. Unquestionably, the automation of these technologies allows for faster sample throughput, greater reproducibility, and radically reduced analysis times. Coated blade spray (CBS) is a μe technology engineered for extracting/enriching analytes of interest in complex matrices, and it can be directly coupled with MS instruments to achieve efficient screening and quantitative analysis. In this study, we introduced CBS as a technology that can be arranged to perform either rapid diagnostics (single vial) or the high-throughput (96-well plate) analysis of biofluids. Furthermore, we demonstrate that performing 96-CBS extractions at the same time allows the total analysis time to be reduced to less than 55 s per sample. Aiming to validate the versatility of CBS, substances comprising a broad range of molecular weights, moieties, protein binding, and polarities were selected. Thus, the high-throughput (HT)-CBS technology was used for the concomitant quantitation of 18 compounds (mixture of anabolics, β-2 agonists, diuretics, stimulants, narcotics, and β-blockers) spiked in human urine and plasma samples. Excellent precision (∼2.5%), accuracy (≥90%), and linearity (R

Coated Blade Spray (CBS) is a technology that efficiently integrates sample preparation and direct coupling to mass spectrometry (MS) on a single device. In this article, we present CBS-tandem mass spectrometry (CBS-MS/MS) as a novel tool for the rapid and simultaneous determination of four commonly used immunosuppressive drugs (ISDs) in whole blood: tacrolimus (TAC) and cyclosporine-A (CycA), which are calcineurin inhibitors; and sirolimus (SIR) and everolimus (EVR), which are both mTOR (mechanistic target of rapamycin) inhibitors. Given that CBS extracts via free concentration, analytes that are largely bound to plasma proteins or red blood cells provide considerably lower extraction recovery rates. Therefore, we defy the solventless philosophy of SPME-based techniques, like CBS, by performing the analyte-enrichment step via direct immersion in a solvent-modified matrix. The assay was linear within the evaluated range of concentrations (between 1 and 100 ng/mL for EVR/SIR/TAC and 10–1000 ng/mL for CycA), and the limits of quantification were determined to be 10 ng/mL for CycA and 1 ng/mL for EVR/SIR/TAC. Good accuracy (87–119%) and linearity (r2 ≥ 0.99) were attained over the evaluated range for all ISDs. Interassay imprecision (CV) determined from incurred sample reanalysis was ≤10% for all ISDs. Our method was validated using Liquichek™ whole blood immunosuppressant quality control (QC) standards purchased from Bio-Rad. Concentrations determined by CBS-MS/MS were inside the range specified by Bio-Rad and within 15% of the expected mean value for all ISDs at all QC levels. Furthermore, the effect of different hematocrit levels (20, 45, and 70%) in the entire calibration range was carefully studied. No statistical differences (RSD ≤ 7%) in the calibration curve slopes of ISDs in blood were observed. CBS offers a simpler workflow than that of traditional methods; it eliminates the need for chromatographic separation and provides a clean extract that allows for long-term MS instrumental operation with minimal maintenance. Additionally, because CBS integrates all analytical steps into one device, it eliminates the risk of instrumental carry-over and can be used as a low-cost disposable device for sample preparation and analysis. Fully-automated sample preparation simplifies the method and allows for total analysis times as short as 3 min with turn-around times of less than 90 min.

To date, solid-phase microextraction (SPME) fibers used for in vivo bioanalysis can be too fragile and flexible, which limits suitability for direct tissue sampling. As a result, these devices often require a sheathing needle to prepuncture robust sample matrixes and protect the extraction phase from mechanical damage. To address this limitation, a new SPME device is herein presented which incorporates an extraction phase recessed into the body of a solid needle. This device requires no additional support or shielding during puncture events through protective tissue. The presented device was thoroughly tested, being fired at 90 m·s–1 through fish scales, forced through vial septa, and employed in a targeted study of polyunsaturated fatty acids in salmon where the protective outer skin was repetitively punctured during sampling. Finally, the recessed SPME device was applied to an on-site application for the tissue analysis of wild muskellunge. With this advancement, rapid, minimally invasive, and easily ex...

Time weighted average (TWA) passive sampling with thin film solid phase microextraction (TF-SPME) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for collection, identification, and quantification of benzophenone-1, benzophenone-2, benzophenone-3, benzophenone-4, 2-phenylbenzimidazole-5-sulfonic acid, octocrylene, octylmethoxycinnamate, butylmethoxydibenzoylmethane, triclocarban and triclosan in the aquatic environment. Two types of TF-SPME passive samplers, including a retracted thin film device using a hydrophilic lipophilic balance (HLB) coating, and an open bed configuration with an octadecyl silica-based (C18)coating, were evaluated in an aqueous standard generation system. Laboratory calibration results indicated that the thin film retracted device using HLB coating is suitable to determine TWA concentrations of polar analytes in water, with an uptake that was linear up to 70 days. In open bed form, a one-calibrant kinetic calibration technique was accomplished by loading benzophenone3-d

The dual nature of the quaternary ammonium compounds, having permanently charged hydrophilic quaternary ammonium heads and long-chain hydrophobic tails, makes the sample preparation step and analysis of these compounds challenging. A high-throughput method based on thin-film solid-phase microextraction (SPME) and liquid chromatography mass spectrometry was developed for simultaneous quantitative analysis of nine benzylic and aliphatic quaternary ammonium compounds. Chromatographic separation and detection of analytes were obtained in reverse-phase mode in 8 min using a triple quadrupole mass spectrometer. Hydrophilic lipophilic balance particle-coated blades were found to be the most suitable among the different coatings tested in terms of recoveries and carryover on the blades. For desorption solvents, 70/30, v/v (A/B) with 0.1 % formic acid (where A is 10 mM ammonium acetate in acetonitrile/water (95/5 , v/v) and B is 0.1 % (v/v) formic acid in isopropyl alcohol) was shown to be the most efficient solvent for the desorption of the analytes from the SPME sorbent. The SPME method was optimised in terms of extraction, pH, and preconditioning, as well as extraction and desorption times. Optimum conditions were 45 min of extraction time and 15 min of desorption time, all with agitation. The extraction was found to be optimum in a range of pH 6.0 to 8.0, which is consistent with the natural pH of water samples. Wide linear dynamic ranges with the developed method were obtained for each compound, enabling the application of the method for a wide range of concentrations. The developed method was validated according to the Food and Drug Administration criteria. The proposed method is the first SPME-based approach describing the applicability of the high-throughput thin-film SPME in a 96-well system for analysis of such challenging compounds.

This article discusses comparison of microextraction versus exhaustive extraction approaches for simultaneous extraction of compounds in wide range of polarity at low and high volumes of sample by comparing solid phase extraction (SPE) and solid phase microextraction (SPME). Here, both systems are discussed theoretically and evaluated based on experimental data. Experimental comparisons were conducted in terms of extraction recovery, sensitivity, and selectivity for the extraction of doping agent compounds (log P: 0.14–4.98), using C18 as the extraction phase. The extraction recovery of both systems was studied at different volumes of phosphate buffered saline (PBS). The distribution constant of SPME in thin-film geometry (i.e., thin-film microextraction/TFME) as well as the retention factor and breakthrough volume for the SPE system were evaluated for the simultaneous extraction of polar and non-polar compounds. Using 1 mL of sample, the extraction recovery and sensitivity of the SPE system (100 mg sorbent) was comparable with that of TFME format of SPME (15 mg sorbent) for all analytes, with the exception of most polar compounds, due to the smaller amount of the extraction phase in SPME. Breakthrough in the SPE system was observed for more polar compounds in a 25 mL sample; however, this situation did not affect the quantitation of TFME, as this technique operates in equilibrium mode. Experimental values for breakthrough volume were in good match with the calculated theoretical values. Results indicate that the microextraction approach is more suitable for untargeted determinations, where the breakthrough volume cannot be determined prior to the experiment. In addition, when both methods are at optimum conditions, findings suggest that, despite the smaller volume of the extraction phase in TFME, the sensitivity of TFME can exceed that of SPE for samples where the target analytes vary substantially in polarity.

In this work, a durable and easy to handle thin film microextraction (TFME) device is reported. The membrane is comprised of poly(divinylbenzene) (DVB) resin particles suspended in a high-density polydimethylsiloxane (PDMS) glue, which is spread onto a carbon fiber mesh. The currently presented membrane was shown to exhibit a substantially lesser amount of siloxane bleed during thermal desorption, while providing a statistically similar extraction efficiency toward a broad spectrum of analytes varying in polarity when compared to an unsupported DVB/PDMS membrane of similar shape and size which was prepared with previously published methods. With the use of hand-portable GC-TMS instrumentation, membranes cut with dimensions 40 mm long by 4.85 mm wide and 40 ± 5 μm thick (per side) were shown to extract 21.2, 19.8, 18.5, 18,4, 26.8, and 23.7 times the amount of 2,4 dichlorophenol, 2,4,6 trichlorophenol, phorate D10, fonofos, chloropyrifos, and parathion, respectively, within 15 min from a 10 ppb aqueous solution as compared to a 65 μm DVB/PDMS solid phase microextraction (SPME) fiber. A portable high volume desorption module prototype was also evaluated and shown to be appropriate for the desorption of analytes with a volatility equal to or lesser than benzene when employed in conjunction with TFME membranes. Indeed, the coupling of these TFME devices to hand-portable gas chromatography toroidial ion trap mass spectrometry (GC-TMS) instrumentation was shown to push detection limits for these pesticides down to the hundreds of ppt levels, nearing that which can be achieved with benchtop instrumentation. Where these membranes can also be coupled to benchtop instrumentation it is reasonable to assume that detection limits could be pushed down even further. As a final proof of the concept, the first ever, entirely on-site TFME-GC-TMS analysis was performed at a construction impacted lake. Results had indicated the presence of contaminants such as toluene, ethylbenzene, xylene, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, and tris(1-chloro-2-propyl)phosphate, which stood out from other naturally occurring compounds detected.

Determination of quaternary ammonium compounds (QACs) often is considered to be a challenging undertaking owing to secondary interactions of the analytes' permanently charged quaternary ammonium head or hydrophobic tail with the utilized labware. Here, for the first time, a micelle assisted thin-film solid phase microextraction (TF-SPME) using a zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) as a matrix modifier is introduced as a novel approach for in-laboratory sample preparation of the challenging compounds. The proposed micelle assisted TF-SPME method offers suppression/enhancement free electrospray ionization of analytes in mass spectrometric detection, minimal interaction of the micelles with the TF-SPME coating, and chromatographic stationary phase and analysis free of secondary interactions. Moreover, it was found that the matrix modifier has multiple functions; when its concentration is found below the critical micelle concentration (CMC), the matrix modifier primarily acts as a surface deactivator; above its CMC, it acts as a stabilizer for QACs. Additionally, shorter equilibrium extraction times in the presence of the modifier demonstrated that micelles also assist in the transfer of analytes from the bulk of the sample to the surface of the coating. The developed micelle assisted TF-SPME protocol using the 96-blade system requires only 30 min of extraction and 15 min of desorption. Together with a conditioning step (15 min), the entire method is 60 min; considering the advantage of using the 96-blade system, if all the blades in the brush are used, the sample preparation time per sample is 0.63 min. Moreover, the recoveries for all analytes with the developed method were found to range within 80.2-97.3%; as such, this method can be considered an open bed solid phase extraction. The proposed method was successfully validated using real samples.

A novel sorbent, chitosan-immobilized pumice, has been prepared for the sorption of As(V) from waters prior to its determination by hydride generation atomic absorption spectrometry. The success of the immobilization has been checked with such characterization techniques as scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. Points of zero charge of the sorbents were determined with potentiometric mass titration. Batch-type equilibration studies have shown that the novel sorbent can be employed at a wide pH range resulting in quantitative sorption (>90 %) at pH 3.0–7.0 and greater than 70 % sorption at pH >8.0. These results demonstrate the advantage of immobilizing chitosan onto pumice, because, under the same conditions, pumice displays

A fully automated, high-throughput method based on thin-film solid-phase microextraction (SPME) and liquid chromatography-mass spectrometry was developed for simultaneous quantitative analysis of 110 doping compounds, selected from ten classes and varying in physical and chemical properties. Among four tested extraction phases, C18 blades were chosen, as they provided optimum recoveries and the lowest carryover effect. The SPME method was optimized in terms of extraction pH, ionic strength of the sample, washing solution, extraction and desorption times for analysis of urine samples. Chromatographic separation was obtained in reversed-phase model; for detection, two mass spectrometers were used: triple quadrupole and full scan orbitrap. These combinations allowed for selective analysis of targeted compounds, as well as a retrospective study for known and unknown compounds. The developed method was validated according to the Food and Drug Administration (FDA) criteria, taking into account Minimum Required Performance Level (MRPL) values required by the World Anti-Doping Agency (WADA). In addition to analysis of free substances, it was also shown that the proposed method is able to extract the glucuronated forms of the compounds. The developed assay offers fast and reliable analysis of various prohibited substances, an attractive alternative to the standard methods that are currently used in anti-doping laboratories.