A study of thin film solid phase microextraction methods for analysis of fluorinated benzoic acids in seawater

Fast Determination of Eleven Food Additives in River Water Using C18 Functionalized Magnetic Organic Polymer Nanocomposite Followed by High-Performance Liquid Chromatography

A novel magnetic nanomaterial with Fe3O4 as the core, PS-DVB as the shell layer, and the surface modified with C18 (C18-PS-DVB-Fe3O4) had been synthesized by seeded emulsion polymerization. C18-PS-DVB-Fe3O4 retains the advantages of the chemical stability, large porosity, and uniform morphology of organic polymers and has the magnetic properties of Fe3O4. A simple, flexible, and efficient magnetic dispersive solid phase extraction (Mag-dSPE) method for the extraction of preservatives, sweeteners, and colorants in river water was established. C18-PS-DVB-Fe3O4 was used as an adsorbent for Mag-dSPE and was coupled with high-performance liquid chromatography (HPLC) to detect 11 food additives: acesulfame, amaranth, benzoic acid, tartrazine, saccharin sodium, sorbic acid, dehydroacetic acid, sunset yellow, allura red, brilliant blue, and erythrosine. Under the optimum extraction conditions, combined with ChromCoreTMAQC18 (5 μm, 4.6 × 250 mm), 20 mmol/L ammonium acetate aqueous solution and methanol were used as mobile phases, and the detection wavelengths were 240 nm and 410 nm. The limits of detection (LODs) of 11 food additives were 0.6-3.1 μg/L with satisfactory recoveries ranging from 86.53% to 106.32%. And the material could be reused for five cycles without much sacrifice of extraction efficiency. The proposed method has been used to determine food additives in river water samples, and results demonstrate the applicability of the proposed C18-PS-DVB-Fe3O4 Mag-dSPE coupled with the HPLC method to environment monitoring analysis.

Investigation of the adsorption/desorption mechanism of perfluoroalkyl substances on HLB-WAX extraction phases for microextraction

The C-F alkyl structural backbone of per- and polyfluoroalkyl substances makes this class of molecules resistant to heat and degradation, leading to their high persistence and mobility in the environment and bioaccumulation in the tissues of living organisms. In this study, 15 PFAS with an alkyl chain length from C₄ to C₁₄, currently monitored by the U.S. Environmental Protection Agency (EPA), were preconcentrated by solid-phase microextraction (SPME) and analyzed by liquid chromatography-tandem mass spectrometry. The adsorption and desorption mechanisms of PFAS onto ion-exchange extraction phases was evaluated to understand the extraction process of PFAS from various environmental matrices under different conditions. This was achieved using two SPME geometries, namely fibers and thin films. The use of thin films resulted in a twofold improvement in extraction efficiency compared to fibers, especially for the short-chain PFAS. Methanol:water (80:20, v/v) was chosen as the optimized desorption solution, with ammonium formate added to minimize carryover. Extraction time profiles for both SPME geometries showed faster equilibration with thin films (30 min) compared to fibers (90-120 min). The linear dynamic range obtained with this method using fibers and thin films ranged from 10 to 5000 ng L^-1 and 2.5-5000 ng L^-1, respectively, with acceptable accuracy (70-130%) and precision (<15%). LOD ranged within 2.5-10 ng L^-1 for fibers and 0.01-0.25 ng L^-1 for thin films. Investigating the factors affecting PFAS recovery in complex samples enabled the quantitative assessment of PFAS contamination in various environmental water samples such as seawater, melted snow and biospecimens like human plasma. A 96-SPME holder was used for validation, which is compatible with sampling in 96-well plates and ensures high throughput in the analysis of real samples. The total concentration of PFAS detected in seawater and snow was 51.3 ng L^-1 and 16.4 ng L^-1, respectively.

Development of the thin film solid phase microextraction (TF-SPME) method for metabolomics profiling of steroidal hormones from urine samples using LC-QTOF/MS

In the present study, the development and optimization of a thin film solid phase microextraction method (TF-SPME) was conducted for metabolomics profiling of eight steroid compounds (androsterone, dihydrotestosterone, dihydroepiandrosterone, estradiol, hydroxyprogesterone, pregnenolone, progesterone and testosterone) from urine samples. For optimization of extraction method, two extraction sorbents (PAN-C18 and PS-DVB) were used as they are known to be effective for isolation of low-polarity analytes. The stages of sample extraction and analyte desorption were considered as the most crucial steps in the process. Regarding the selection of the most suitable desorption solution, six different mixtures were analyzed. As a result, the mixture of ACN: MeOH (1:1, v/v) was chosen in terms of the highest analytes' abundances that were achieved using the chosen solvent. Besides other factors were examined such as the volume of desorption solvent and the time of both extraction and desorption processes. The analytical determination was carried out using the ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometry detection in electrospray ionization and positive polarity in a scan mode (UHPLC-ESI-QTOF/MS). The developed and optimized TF-SPME method was validated in terms of such parameters as extraction efficiency, recovery as well as matrix effect. As a result, the extraction efficiency and recovery were in a range from 79.3% to 99.2% and from 88.8% to 111.8%, respectively. Matrix effect, calculated as coefficient of variation was less than 15% and was in a range from 1.4% to 11.1%. The values of both validation parameters (recovery and matrix effect) were acceptable in terms of EMA criteria. The proposed TF-SPME method was used successfully for isolation of steroids hormones from pooled urine samples before and after enzymatic hydrolysis of analytes.

Designing an "all-in-one" microextraction capsule device for the liquid chromatographic-fluorescence determination of doxorubicin and its metabolites in rat plasma

In this study, an "all-in-one" microextraction device was designed and fabricated for the extraction of doxorubicin and its two metabolites from rat plasma prior to their determination by high performance liquid chromatography coupled to fluorescence detector. A sol-gel-based sorbent was synthesized in situ and incorporated within two conjoined porous polypropylene tubes together with a cylindrical magnetic bar in order to avoid the need of an external stirring bar. Among other sorbents investigated, the moderately polar sol-gel poly(tetrahydrofuran) was found to be advantageous due to its high affinity toward the target analytes. Systematic investigation of the critical parameters affecting the adsorption and the desorption step was carried out. Due to the "built-in" filtration mechanism of the porous microextraction capsules, the isolation of the analytes was performed directly in the plasma matrix without any previous sample pretreatment (i.e., protein precipitation, centrifugation, etc.). The proposed method was validated in terms of linearity, accuracy, precision, specificity, sensitivity, and stability according to the FDA guidelines. The limits of detection ranged between 1 - 2 ng mL^-1 while the lower limits of quantitation of the analytes were calculated as 10 ng mL^-1. The accuracy (% relative error) was found within -9.7 - 15.3% under both intra- and inter-day conditions. The precision was better than 13.4% in all cases. ComplexGAPI index was employed to present the green attributes of the developed protocol from the preparation of the microextraction device to the final determination of the analytes. Finally, the applicability of the fabricated stand-alone extraction device was demonstrated in the analysis of the target analytes in rat plasma after intravenous administration of doxorubicin in order to assess its pharmacokinetic profile.

Advances in the analytical methods for the determination of fluorinated aromatic carboxylic acids in aqueous matrices: A review

Fluorobenzoic acids are critically important chemical tracers in hydrothermal, geothermal, leaching, and oilfield applications. Particularly in oilfield applications, these tracers are used to investigate fluid flow paths between injector wells and producer wells, providing valuable information about the enhanced oil recovery process of the oil reservoirs. The detection limit of tracers is a vital subject in field reservoir work because the amount of chemical tracer that must be injected into the injector well is directly related to the amount detected at the producer well after migration and diffusion. The popularity of fluorinated benzoic acids as the tracers is due to their non-toxicity over radioactive tracers and low detection limit, which is determined using analytical techniques. This review focuses on the improvements/developments in extraction techniques such as solid-phase extraction and determination techniques such as gas chromatography coupled with mass spectrometry, liquid chromatography with mass spectrometry, isotope dilution gas chromatography-mass spectrometry, high-performance liquid chromatography, ion chromatography coupled with electrospray mass spectrometry, and so on for the analysis of fluorinated benzoic acids to achieve the lowest possible limit of concentration.

High-throughput biomonitoring of organophosphate flame-retardant metabolites in urine via 96-blade solid-phase microextraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry

Organophosphate flame retardants (OPFRs) are widely used in consumer products and building materials, but their propensity for migration poses a problem with respect to polluting indoor environments, water, soil, and dust. OPFR metabolites in urine samples are appropriate biomarkers for assessing exposure risk levels. In this paper, a high-throughput method that couples 96-blade solid-phase microextraction with ultra-performance liquid chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS) is applied for the simultaneous detection of four OPFR metabolites in urine samples. The results indicated that the best extraction was achieved using 96 blades coated with hydrophilic-lipophilic balance weak anion exchange (HLB-WAX). The proposed SPME method's extraction efficiency was maximized by optimizing extraction time, pH value, desorption solution, desorption volume, and desorption time, and it was validated in accordance with the Food and Drug Administration's guidelines. The findings indicated that the proposed method has a wide linearity range (0.5-100 ng mL^-1) and low detection limits (0.09-0.14 ng mL^-1). The method's accuracy ranged from 98% to 118%, with intra-day precision ranging from 1% to 10%. In contrast, inter-day precision ranged from 3% to 16%. Accuracy was also evaluated using independent urine samples, which ranged from 78% to 124% with corresponding relative standard deviations (1%-16%). Ultimately, DoCP was detected in two real samples at a concentration of 0.5-1.1 ng mL^-1, and BEHP was detected at a concentration of 0.2-1.2 ng mL^-1. Overall, the proposed SPME-UPLC-MS/MS method is reliable, accurate, and capable of simultaneously determining four OPFR metabolites in urine samples and screening them to assess exposure risk for humans.

Determination of phase-partitioning tracer candidates in production waters from oilfields based on solid-phase microextraction followed by gas chromatography-tandem mass spectrometry

In the present document, we report the development of an analytical method consisting of a sequential direct-immersion/headspace solid-phase microextraction (DI-HS-SPME) followed by gas-phase chromatography and tandem mass spectrometry (GC-MS/MS) for simultaneous analysis of 4-chlorobenzyl alcohol, 2,6-dichlorobenzyl alcohol, 4-methoxybenzyl alcohol, 3,4-dimethoxybenzyl alcohol, pyridine, and 2,3-dimethylpyrazine in oilfield production waters. These compounds are under evaluation for use as phase-partitioning tracers in oil reservoirs. To the best of our knowledge, this is the first time SPME has been applied to the analysis of these compounds in production waters, or any other type of matrix where the compounds targeted are the base for a technical application. Relevant extraction parameters, such as the adsorbent phase of the fiber, direct immersion or headspace, addition of salt, temperature and time of extraction were investigated. The final optimal operation conditions consist on extracting 5 mL of sample at pH 9.0 with 1.8 g of NaCl with constant stirring during 5 minutes of DI-SPME followed by 15 minutes of HS-SPME at 70 °C using a DVB/CAR/PDMS (50/30 µm) fiber. The limits of quantification (LOQ), linearity, precision and accuracy of the method were evaluated. Analyses of the tracer compounds and recovery studies were also performed on production waters from 8 different oilfields of the Norwegian continental shelf. LOQs between 0.080 and 0.35 µg L^-1 were obtained. The recovery yields of the method were consistently higher than 85% and RSDs less than 13%. None of the tracer compounds was found in the real samples processed, which is consistent with one of the requirements for an artificial tracer in an oilfield: absence or constant and low background in the traced fluid. The performance of the method developed, combined with its easiness to automate, introduce a new, accurate and cost-efficient technique to process the hundreds of samples required by an inter-well tracer test.

Systematic Evaluation of Different Coating Chemistries Used in Thin-Film Microextraction

A systematic evaluation of eight different coatings made of solid phase extraction (SPE) and carbon-based sorbents immobilized with polyacrylonitrile in the thin-film microextraction (TFME) format using LC-MS/MS was described. The investigated coatings included graphene, graphene oxide, multi-walled carbon nanotubes (MWCNTs), carboxylated MWCNTs, as carbon-based coatings, and polystyrene-divinylbenzene (PS-DVB), octadecyl-silica particles (C18), hydrophilic-hydrophobic balance particles (HLB) and phenyl-boronic acid modified particles (PBA), as SPE-based coatings. A total of 24 compounds of diverse moieties and of a wide range of polarities (log P from -2.99 to 6.98) were selected as probes. The investigated coatings were characterized based on their extraction performance toward the selected probes at different pH values and at optimized desorption conditions. In the case of SPE-based coatings, PS-DVB and HLB exhibited a balanced extraction for compounds within a wide range of polarities, and C18 showed superior extraction recoveries for non-polar analytes. Carbon-based coatings showed high affinity for non-polar compounds given that their main driving force for extraction is hydrophobic interactions. Interestingly, among the studied carbon-based coatings, graphene oxide showed the best extraction capabilities toward polar compounds owing to its oxygen-containing groups. Overall, this work provided important insights about the extraction mechanisms and properties of the investigated coatings, facilitating the coating selection when developing new TFME applications.

Comparison of the Novel Thin Film-Solid Phase Microextraction and Sorptive Extraction Methods for Picual and Hojiblanca Olive Oil Volatile Fraction Analysis in Headspace

For first time, the new device named thin film solid phase microextraction (TF-SPME) has been used to determine the volatile profile of the Picual and Hojiblanca varieties of extra virgin olive oils. To this end, different traditional sampling methods such as headspace sorptive extraction (HSSE) with polydimethylsiloxane (PDMS) and polyethyleneglycol-modified silicone (EG/Silicone) Twisters^® have been compared with the TF-SPME devices coated with different extraction polymeric phases. PARADISe software was used as a non-targeting method to process all data. The best results were obtained by HSSE-PDMS and 2TF-SPME. Moreover, the 2TF-SPME extraction method achieved the most adequate results of linearity for most compounds, according to F-values, while the intermediate precision results were similar for both 2TF-SPME and HSSE-PDMS sampling methods. Different sensitivity was observed between both sampling methods depending on the volatile compound, without being clearly influenced by the polarity of them. Although both sampling methods enabled the main active aroma of olive oil to be determined and for them to be differentiated according to olive variety, the 2TF-SPME method appears to be the most suitable for this goal.

Development of a thin-film solid-phase microextraction (TF-SPME) method coupled to liquid chromatography and tandem mass spectrometry for high-throughput determination of steroid hormones in white sucker fish plasma

Steroid hormones (SH) play a number of important physiological roles in vertebrates including fish. Changes in SH concentration significantly affect reproduction, differentiation, development, or metabolism. The objective of this study was to develop an in vitro high-throughput thin-film solid-phase microextraction (TF-SPME)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for targeted analysis of endogenous SH (cortisol, testosterone, progesterone, estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2)) in wild white sucker fish plasma where the concentrations of the analytes are substantially low. A simple TF-SPME method enabled the simultaneous determination of free and total SH concentrations. The use of biocompatible coating allowed direct extraction of these hormones from complex biological samples without prior preparation. The carryover was less than 3%, thereby ensuring reusability of the devices and reproducibility. The results showed that TF-SPME was suitable for the analysis of compounds in the polarity range between 1.28 and 4.31 such as SH at different physicochemical properties. The proposed method was validated according to bioanalytical method validation guidelines. The limit of detection (LOD) and limit of quantification(LOQ) for cortisol, testosterone, progesterone, E1, E2, and EE2 were from 0.006 to 0.150 ng/mL and from 0.020 to 0.500 ng/mL, respectively. The recovery for the method was about 85%, and the accuracy and precision of the method for cortisol, testosterone, and progesterone were ≤ 6.0% and ≤ 11.2%, respectively, whereas those for E1, E2, and EE2 were ≤ 15.0% and ≤ 10.2%, respectively. On the basis of this study, TF-SPME demonstrated several important advantages such as simplicity, sensitivity, and robustness under laboratory conditions. Graphical abstract.

Development, Optimization and Applications of Thin Film Solid Phase Microextraction (TF-SPME) Devices for Thermal Desorption: A Comprehensive Review

Through the development of solid phase microextraction (SPME) technologies, thin film solid phase microextraction (TF-SPME) has been repeatedly validated as a novel sampling device well suited for various applications. These applications, encompassing a wide range of sampling methods such as onsite, in vivo and routine analysis, benefit greatly from the convenience and sensitivity TF-SPME offers. TF-SPME, having both an increased extraction phase volume and surface area to volume ratio compared to conventional microextraction techniques, allows high extraction rates and enhanced capacity, making it a convenient and ideal sampling tool for ultra-trace level analysis. This review provides a comprehensive discussion on the development of TF-SPME and the applications it has provided thus far. Emphasis is given on its application to thermal desorption, with method development and optimization for this desorption method discussed in detail. Moreover, a detailed outlook on the current progress of TF-SPME development and its future is also discussed with emphasis on its applications to environmental, food and fragrance analysis.

Fast screening of illicit drugs in beverages and biological fluids by direct coupling of thin film microextraction to dielectric barrier discharge ionization-mass spectrometry

A direct and fast method for quantification of illicit drugs in beverages and biological fluids was developed, using dielectric barrier discharge ionization in combination with high-resolution MS.

Coated blade spray: shifting the paradigm of direct sample introduction to MS

Coated blade spray (CBS) is a solid-phase microextraction-based technology that can be directly coupled to MS to enable the rapid qualitative and quantitative analysis of complex matrices. The goal of this mini review is to concisely introduce CBS's operational fundamentals and to consider how it correlates/contrasts with existing direct-to-MS technologies suitable for bioanalytical applications. In addition, we provide a fair comparison of CBS to other existing solid-phase microextraction-to-MS approaches, as well as an overview of recent CBS applications/strategies that have been developed to analyze diverse compounds present in biofluids.

In-syringe solid-phase extraction for on-site sampling of pyrethroids in environmental water samples

On-site sampling is an analytical approach that can ensure the accuracy of monitoring data and enhance the effectiveness of environmental protection measures. In the present work, an in-syringe solid-phase extraction (SPE) device was designed for on-site sampling of trace contaminants in environmental water samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Template assisted freeze casting followed by hydrazine vapor reduction approach was used to synthesize a hierarchical porous graphene aerogel (HPGA), which was used as the sorbent in the in-syringe SPE device. Environmental degradable pyrethroids were selected as the model analytes. Owing to the large specific surface area and hydrophobicity of HPGA, the target molecules could be completely extracted during one aspirating/dispensing cycle. The analytes were stable on the sorbent for at least 72 h when the device was stored under airtight and light-free conditions, and were not affected by the pH value of sample solution. All results demonstrated that the device could meet the requirements of on-site sampling. For practical application, the limits of detection were found to be in the range of 0.012-0.11 ng mL^-1 under the optimized conditions, and satisfactory recoveries in the range of 65.7-105.9% were obtained for the analysis of real samples. The results of this study demonstrate the immense potential of HPGA for the enrichment of trace environmental pollutants, and meanwhile promote the application of the in-syringe SPE technique as a promising candidate for on-site sampling.

High-Throughput Screening and Quantitation of Target Compounds in Biofluids by Coated Blade Spray-Mass Spectrometry

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 (R² ≥ 0.99) were attained for all the studied compounds, and the limits of quantitation (LOQs) were within the range of 0.1 to 10 ng·mL^-1 for plasma and 0.25 to 10 ng·mL^-1 for urine. The results reported in this paper confirm CBS's great potential for achieving subsixty-second analyses of target compounds in a broad range of fields such as those related to clinical diagnosis, food, the environment, and forensics.