Application Of Solid-phase Microextraction Research Articles

Application of solid-phase microextraction and LCMS/MS for the detection of pesticide residues

Aiming at the organophosphorus pesticide residues in tea, a method integrating solid-phase microextraction and liquid chromatography-mass spectrometry was investigated for the detection of organophosphorus pesticide residues in tea. Firstly, the conditions in the process were optimized; then the method was established to analyze the organophosphorus pesticides in tea; finally, the method feasibility was verified by using actual sample determination. In terms of the results, the standard curve correlation coefficients of the solid-phase microextraction and liquid chromatography-mass spectrometry methods used in the study were greater than 0.99, while the average recoveries ranged from 72 to 109% with the relative standard deviations (RSDs) of less than 9.0%. This indicates that the method has a good linear range, low detection limit and high recovery. In the application validation in real samples, the concentrations of organophosphorus pesticide residues in tea were within the safe range. The method was validated to be suitable for the monitoring and control of organophosphorus pesticide residues in tea with low cost and simplified sample preparation.

Controlled construction of 2D hierarchical core-shell ZnO/MnO2 nanosheets on Nitinol fiber with enhanced adsorption performance for selective solid-phase microextraction of trace polycyclic aromatic hydrocarbons in water samples

BackgroundPolycyclic aromatic hydrocarbons (PAHs) are an important class of potentially toxic persistent organic pollutants in environmental water. Their concentrations are usually too low to allow for direct determination with analytical instruments, and the preconcentration is required prior to instrumental analysis. Solid phase microextraction (SPME) is considered as a high-performance green sample preparation technique for volatile and non-volatile organic compounds due to its high enrichment factor. In fact, the nature of SPME coatings governs the adsorption performance. Therefore, more efforts have devoted to the controlled construction of novel long-life SPME fibers with enhanced adsorption performance and improved adsorption selectivity. Results2D hierarchical core-shell ZnO/MnO2 nanosheets (NSs) were constructed on a Nitinol (NiTi) fiber substrate by layer-by-layer assembly for enhanced and selective SPME of PAHs. Firstly, hexagonal ZnO NSs were electrodeposited on the NiTi substrate. Subsequently smaller secondary MnO2 NSs were uniformly grown on the surface of ZnO NSs by a facile hydrothermal oxidation process. ZnO NSs were well protected by the chemically stable MnO2 shell, making the coating highly durable and efficient for SPME application. Meanwhile, the ZnO/MnO2 NSs coating demonstrated superior adsorption performance for PAHs. After the optimization of SPME conditions, the proposed SPME-HPLC-UV method exhibited good analytical performance for preconcentrating and determining trace PAHs with wide linear ranges (0.03–200 μg L−1) and low LODs (0.005–0.112 μg L−1) as well as good repeatability (1.4%-6.9%) and fiber-to-fiber reproducibility (5.3%-7.1%). Moreover, the proposed method showed good precision and recovery in the preconcentration and determination of target PAHs in real water samples. SignificanceAs compared with representative commercially available fibers, the NiTi@ZnO/MnO2 NSs fiber showed enhanced adsorption efficiency and improved adsorption selectivity for PAHs. The constructed fiber can be used as an alternative to commercial fibers for the adsorption and preconcentration of target PAHs in the environmental water samples. Moreover, the preparation strategy is expected to provide new insights into the precisely controlled construction of the efficient and stable core-shell bimetallic oxide nanostructures on the superielastic NiTi-based fibers.

Hierarchical covalent organic framework hollow nanofibers-bonded stainless steel fiber for efficient solid phase microextraction

The solid phase microextraction (SPME) technique has been widely applied in the detection of trace compounds in food, environment, and medicine due to its advantages of easy quantification, simple operation, and greenness. Herein, a templating strategy with SiO2 nanofibers (SiO2 NFs) is reported to synthesize hierarchical covalent organic framework hollow nanofibers (COF HNFs)-coated stainless steel fiber for SPME application with dramatically enhanced enrichment performance for trace analytes. The construction of hierarchical porosity inside the microextraction coatings can not only increase the specific surface area of COF extraction materials for obtaining more abundant adsorption sites but also greatly improve the accessibility of internal COF micropores. Moreover, the thicknesses of the microextraction COF coatings can be facilely tailored by adjusting the amount of SiO2 NFs pre-assembled on the SPME fibers. On the headspace solid phase microextraction (HS-SPME) of antimicrobial residues, the developed COF TpBD-Me2 HNFs-12 fibers achieve enrichment factors of 2026 and 1823 for thymol and carvacrol respectively, which are significantly higher than those obtained from the counterpart COF TpBD-Me2-bonded fiber (8.5–8.2 times) and commercial CAR/PDMS fiber (3.3–4.4 times). Furthermore, the developed method was demonstrated to have wide linearity (0.1–50 μg L-1), low limits of detection (0.010 μg L-1), good thermal stability and excellent reusability (>60 recycles), demonstrating great application potential in the extraction of trace organic pollutants. The strategy developed in this work is applicable to preparing a variety of topological COF (e.g., TpBD, TpPa-1) HNFs-bonded fibers.

Applications of functional materials-based solid phase microextraction technique in forensic science

Sample extraction is a crucial step in forensic analysis, especially when dealing with trace and ultra-trace levels of target analytes present in various complex matrices (e. g., soil, biological samples, and fire debris). Conventional sample preparation techniques include Soxhlet extraction and liquid-liquid extraction. However, these techniques are tedious, time-consuming, labor-intensive and require large amounts of solvents, which poses a threat to the environment and health of researchers. Moreover, sample loss and secondary pollution can easily occur during the preparation procedure. Conversely, the solid phase microextraction (SPME) technique either requires a small amount of solvent or no solvent at all. Its small and portable size, simple and fast operation, easy-to-realize automation, and other characteristics thus make it a widely used sample pretreatment technique. More attention was given to the preparation of SPME coatings by using various functional materials, as commercialized SPME devices used in early studies were expensive, fragile, and lacked selectivity. Examples of those functional materials include metal-organic frameworks, covalent organic frameworks, carbon-based materials, molecularly imprinted polymers, ionic liquids, and conducting polymers, all widely used in environmental monitoring, food analysis, and drug detection. However, these SPME coating materials have relatively few applications in forensics. Given the high potential of SPME technology for the in situ and efficient extraction of samples from crime scenes, this study briefly introduces functional coating materials and summarizes the applications of SPME coating materials for the analysis of explosives, ignitable liquids, illicit drugs, poisons, paints, and human odors. Compared to commercial coatings, functional material-based SPME coatings exhibit higher selectivity, sensitivity, and stability. These advantages are mainly achieved through the following approaches: First, the selectivity can be improved by increasing the π-π, hydrogen bonds, and hydrophilic/hydrophobic interactions between the materials and analytes. Second, the sensitivity can be improved by using porous materials or by increasing their porosity. Third, thermal, chemical, and mechanical stability can be improved by using robust materials or fixing the chemical bonding between the coating and substrate. In addition, composite materials with multiple advantages are gradually replacing the single materials. In terms of the substrate, the silica support was gradually replaced by the metal support. This study also outlines the existing shortcomings in forensic science analysis of functional material-based SPME techniques. First, the application of functional material-based SPME techniques in forensic science remains limited. On one hand, the analytes are narrow in scope. As far as explosive analysis is concerned, functional material-based SPME coatings are mainly applied to nitrobenzene explosives, while other categories, such as nitroamine and peroxides, are rarely or never involved. Research and development of coatings is insufficient and the application of COFs in forensic science has not yet been reported. Second, functional material-based SPME coatings have not been commercialized as they don't yet have inter-laboratory validation tests or established official standard analytical methods. Therefore, some suggestions are proposed for the future development of forensic science analyses of functional material-based SPME coatings. First, research and development of functional material-based SPME coatings, especially fiber coatings with broad-spectrum applicability and high sensitivity, or outstanding selectivity for some compounds, is still an important direction for SPME future research. Second, a theoretical calculation of the binding energy between the analyte and coating was introduced to guide the design of functional coatings and improve the screening efficiency of new coatings. Third, we expand its application in forensic science by expanding the number of analytes. Fourth, we focused on the promotion of functional material-based SPME coatings in conventional laboratories and established performance evaluation protocols for the commercialization of functional material-based SPME coatings. This study is expected to serve as a reference for peers engaged in related research.

Application of solid-phase microextraction in atomic spectrometry

With the growing requirements for the monitoring of heavy metals at an ultra-trace level in the environment and the real-time detection of toxic elements and their compounds for environmental pollution accidents, researchers devoted significant efforts to seeking atomic spectrometric methods that can be used for the simple, low cost, rapid, and field usable detection of targeted elements and their pollutants. Although conventional atomic spectrometric methods can easily realize the routine analysis of toxic elements in various samples in the laboratory, their bulky instruments and the complex sample matrix of environmental samples limit their further applications in field environmental analysis and complex sample analysis. Solid-phase microextraction (SPME) is an environmentally-friendly sample pre-treatment technique, which can significantly simplify sample pretreatment, increase sensitivity, and reduce the interference from the sample matrix, thus being one of the most ideal sampling techniques for the detection of ultra-trace toxic elements and their compounds by atomic spectrometry (AS) with high sensitivity and good selectivity. During the past decades, significant developments of SPME-AS including novel coating nanomaterials, desorption mode, miniaturized spectrometer, and its use for field elemental analysis have been made to improve the analytical performance in the detection of toxic elements and their pollutants. Herein, we present a short review concerning recent advances in elemental analysis by SPME-AS. Particularly, we highlight their application in the field of environmental analysis based on combing SPME with the available microplasma-based atomic spectrometer. The conclusion section addresses the current challenges and gives an outlook on potential future trends in the field of elemental analysis and elemental speciation analysis.

An Overview on the Application of Solid Phase Microextraction in the Analysis of Volatile Organic Compounds as Potential Biomarkers of Cancer

The search for biomarkers of diseases, especially for the early detection of cancer, is one of the most popular research fields in biomedicine. The development of non-invasive screening techniques for the early detection of cancer is one of the greatest scientific challenges of the 21st century. Because various diseases cause to generation of biomarkers in the body, early diagnosis of diseases can be performed by analyzing these biomarkers in all body feces. Detection of volatile organic compounds (VOCs) as biomarkers of the body's metabolic processes is a new frontier in the fast, sensitive, selective and non-invasive analysis and medical diagnosis of human diseases. VOCs as biomarkers in the human body can be distinct and specific to metabolic conditions or diseases. VOCs produced as end products of cellular metabolism and are released through a variety of biological matrices such as breath, blood, saliva, urine and feces. The study of volatile metabolites in the body fluids of the patients is performed to establish "potential biomarkers" for early diagnosis and prognosis of the disease. Various genetic, epigenetic, proteomic, and metabolic markers are evaluated for early detection of cancer. One of the promising emerging methods for early detection of cancer is the analysis of VOCs. The purpose of this review is to provide insights for recent research work on the analysis of VOC-biomarker of cancers with extraction by solid phase microextraction (SPME), and how to detect VOCs in different body matrices as a potential biomarker of disease.

Solid-phase microextraction: a fit-for-purpose technique in biomedical analysis.

Solid-phase microextraction (SPME) possesses unique features that allow it to be used in analyses that would not be possible with traditional sample-preparation methods. The simplicity of SPME protocols and extraction devices makes it a uniform platform for analyzing biological samples, either via the headspace or in direct immersion mode. Furthermore, flexible probe design enables SPME to be applied to target objects of different sizes, offering analysis on a scale ranging “from single cell to living organs”. SPME microfibers are minimally invasive, which enables them to be applied for the spatial and temporal monitoring of target analytes or to assess changes in the entire metabolome or lipidome. Furthermore, SPME permits the capture of the elusive portion of the metabolome, thus complementing exhaustive methods that are biased towards highly abundant and stable species. Significantly, SPME can be interfaced with analytical instrumentation to create a rapid diagnostic tool. However, despite these advantages, SPME has some limitations that must be well-understood and addressed. This paper presents examples of up-to-date applications of SPME, challenges related to particular studies, and future perspectives regarding the application of SPME in biomedical analysis.

Quantitative Analysis of Indoor Gaseous Semi-Volatile Organic Compounds Using Solid-Phase Microextraction: Active Sampling and Calibration

Semi-volatile organic compounds (SVOCs) are important pollutants in indoor environments. Quantification of gaseous SVOC concentrations is essential to assess the pollution levels. Solid-phase microextraction (SPME) is considered to be an attractive sampling technique with merits, including simplicity of use, rapid sampling, and solvent free. However, the applications of SPME for sampling gaseous SVOCs are often limited by the fluctuating velocity of indoor air (leading to an unstable sampling rate) and the uncertainties associated with the traditional calibration of SPME. Therefore, we established an SPME-based active sampler to ensure the stable sampling of SVOCs in fluctuating air and developed a two-step calibration method based on the sampling principle of SPME. The presented method and a traditional method (sorbent tubes packed with Tenax TA) were simultaneously used to measure SVOC concentrations in an airstream generated in experiments. Three typical indoor SVOCs, diisobutyl phthalate (DiBP), tris (1-chloro-2-propyl) phosphate (TCPP), and benzyl butyl phthalate (BBzP) were chosen as the analytes. Mean concentrations measured by SPME agreed well with the sorbent tubes (relative deviations <12%), supporting the feasibility of the presented method. Further studies are expected to facilitate the application of the presented method (especially the problem associated with the sampling-tube loss of low volatile SVOCs).

Volatile organic compounds present in jerked beef, a traditional Brazilian meat product

Jerked beef (JB) is a salty and dry meat product, which is considered the evolution of traditional charque (CH). Despite being a product subject to inspection by several government spheres, its production process may suffer some variations depending on the manufacturer, as the Technical Regulation of Identity and Quality of the product does not establish the time allocated to each processing step. The determination of volatile organic compounds (VOC) can reveal characteristic substances of the food and possible quality markers. The application of solid-phase microextraction in the headspace, in series with gas chromatography coupled with mass spectrometry (HS/SPME-GC/MS), allowed the detection of 103 VOC, among acids, ketones, aldehydes, amines, alcohols, hydrocarbons, ethers, esters and others. Acetic, butanoic and pentanoic acids were identified and associated with the characterization of the JB product, having already been correlated in previous studies to deterioration in fresh meat. Compounds possibly from the migration of plastic packagings, such as caprolactam and oxalic acid, were observed in the analyzed samples.

In Vivo Solid-Phase Microextraction and Applications in Environmental Sciences.

Solid-phase microextraction (SPME) is a well-established sample-preparation technique for environmental studies. The application of SPME has extended from the headspace extraction of volatile compounds to the capture of active components in living organisms via the direct immersion of SPME probes into the tissue (in vivo SPME). The development of biocompatible coatings and the availability of different calibration approaches enable the in vivo sampling of exogenous and endogenous compounds from the living plants and animals without the need for tissue collection. In addition, new geometries such as thin-film coatings, needle-trap devices, recession needles, coated tips, and blades have increased the sensitivity and robustness of in vivo sampling. In this paper, we detail the fundamentals of in vivo SPME, including the various extraction modes, coating geometries, calibration methods, and data analysis methods that are commonly employed. We also discuss recent applications of in vivo SPME in environmental studies and in the analysis of pollutants in plant and animal tissues, as well as in human saliva, breath, and skin analysis. As we show, in vivo SPME has tremendous potential for the targeted and untargeted screening of small molecules in living organisms for environmental monitoring applications.

Crystal violet-modified HKUST-1 framework with improved hydrostability as an efficient adsorbent for direct solid-phase microextraction.

Metal-organic frameworks (MOFs) have received extensive attention in adsorption applications owing to their high surface area. However, some MOFs do not perform well as the extraction medium when used under aqueous conditions. The low hydrostability of MOFs limits the practical application of these materials in solid-phase microextraction (SPME). Here, the fabrication of a water resistance SPME fiber coating is introduced based on the crystal violet (CV)-modified HKUST-1 framework on copper (Cu@HKUST-1@CV). The HKUST-1 was prepared by the in situ growth method, followed by post-synthetic modification of HKUST-1 with the CV layer. The preparation of the modified HKUST-1 was characterized by FESEM, XRD, FTIR, and DFT approaches. The prepared SPME coating was successfully employed for the quantification of anthracene (AN), as a model analyte, in water samples. The limit of detection was 0.8 ng mL-1. The developed method will open up a new door towards searching for promising materials in SPME applications.

Multi-class pesticide analysis in cannabis oil using coated blade spray and solid-phase microextraction with liquid chromatography coupled to mass spectrometry

The application of solid-phase microextraction (SPME) coupled to mass spectrometry to provide a high-throughput and cost-effective solution to multi-residue analysis of pesticides in cannabis oil samples has not been extensively explored. In this work, the method development steps for the extraction of an initial target list of 74 pesticides from cannabis oil via SPME for analysis with both LC-MS/MS and coated blade spray (CBS) are presented. The exploration of a washing step to remove adhered oil whilst minimally desorbing extracted analytes along with the implementation of central composited design investigation to examine compound extraction kinetics in the non-polar matrix yielded a workflow that was validated via both instrumental techniques. Of the initial target list, 37 pesticides were found to be suitable for screening or quantitation via CBS with performance validated via LC-MS/MS. The majority of compounds were found to meet the EU SANTE guidelines for analysis (i.e. linearity, precision, accuracy) whilst reaching limits of quantitation below or at Health Canada minimum regulatory limits (majority at 10 ng/mL). Examination of factors contributing to poor quantitation of pesticides via CBS are shared and explored, such as contributing isobaric interference sourced from plant byproducts and carrier oil, and comparison of signal-to-noise values achieved in cannabis oil when compared to the cannabis-free medium-chain triglyceride oil used as a carrier oil to stress the importance of matrix-match method development.

Nitrogen-doped porous biochar derived from marine algae for efficient solid-phase microextraction of chlorobenzenes from aqueous solution

Nitrogen-doped porous biochar (NPB) with a large specific surface area, wide pore size distribution, graphitized structure, nitrogen doping, and hydrophobicity was fabricated by high-temperature modification of algal biochar with potassium carbonate. This NPB was then uniformly coated on stainless steel wire as a novel solid-phase microextraction (SPME) fiber. The extraction efficiency of NPB-coated fiber for seven chlorobenzenes (CBs) was excellent; it was 1.0–112.2 times higher than that of commercial SPME fibers. A trace determination method was developed for seven CBs in water with the optimized extraction conditions by NPB-coated fiber and gas chromatography–electron capture detector, which showed wide linear ranges (1–1000 ng L−1), low detection limits (0.007–0.079 ng L−1), great repeatability (2.5–6.5% for intra-day, and 3.1–6.8% for inter-day), and excellent reproducibility (3.5–6.3%, n = 5). The practicality of the developed method was evaluated using real water samples and showed great recoveries (89.55–105.19%). This study showed that low-cost biomass wastes could be converted to advanced biochar materials by a facile method, and displayed excellent performance in SPME applications.

Nanosorbent-based solid phase microextraction techniques for the monitoring of emerging organic contaminants in water and wastewater samples.

This review (including 127 refs) summarizes applications of nanosorbent-based solid phase microextraction (SPME) for the cleanup, extraction, and quantification of Emerging Organic Contaminants (EOCs). SPME is the most widely used technique for the analysis of EOCs from water samples. The selection of sorbent material plays a key role in SPME applications. Here, we have collected information about recent developments in the application of nanosorbents in the SPME technique used for the extraction of EOCs from water and wastewater samples. In this review, the preparation, properties, advantages, and limitations of nanosorbents used in SPME applications are evaluated and discussed. Besides, the applications of these nanosorbents in SPME-based extraction techniques and their analytical characteristics for the determination of EOCs are reviewed. Graphical abstract.

Recent Advances in In Vivo SPME Sampling

In vivo solid-phase microextraction (SPME) has been recently proposed for the extraction, clean-up and preconcentration of analytes of biological and clinical concern. Bioanalysis can be performed by sampling exo- or endogenous compounds directly in living organisms with minimum invasiveness. In this context, innovative and miniaturized devices characterized by both commercial and lab-made coatings for in vivo SPME tissue sampling have been proposed, thus assessing the feasibility of this technique for biomarker discovery, metabolomics studies or for evaluating the environmental conditions to which organisms can be exposed. Finally, the possibility of directly interfacing SPME to mass spectrometers represents a valuable tool for the rapid quali- and quantitative analysis of complex matrices. This review article provides a survey of in vivo SPME applications focusing on the extraction of tissues, cells and simple organisms. This survey will attempt to cover the state-of- the-art from 2014 up to 2019.

A Systematic Review of Solid-Phase Microextraction Applications in the Forensic Context.

Since the introduction in 1990, the solid-phase microextraction (SPME) technology has brought significant progress in many fields of forensic sciences due to the versatility of this fast and solventless alternative to conventional extraction techniques. A systematic review about SPME applications in forensic context from January 1995 to June 2018 was carried out according to systematic review guidelines. The majority of the reviewed articles (40/133) aimed to identify drugs (cannabinoids, cocaine, opiates, amphetamines, simultaneous detection of different drugs of abuse, prescribed drugs); 29 of the 133 articles focused on the investigation of fatalities; 28 of the 133 papers used headspace SPME technique for the identification of markers of chronic alcohol abuse. Sixteen papers involved this technique for the isolation of volatile organic compounds for the human odor profile and 20 concerned forensic applications regarding living people. Solid-phase microextraction was preferably employed in the headspace mode and many kinds of fibers were employed, although polydimethylsiloxane was the most adaptable to many forensic realities. Gas chromatography/mass spectrometry was more frequently used, probably for the well-established coupling with SPME. Most of the papers validated their method to harmonize the scientific approaches of procedures development. Good outcomes are reported on biological material collected from living people as well as on cadaveric samples. The results obtained by most of the studies about alcohol biomarkers on scalp hair have been adopted by the "Society of Hair Testing" to demonstrate abstinence over a pre-defined time period and to assess chronic excessive alcohol consumption.

Recent Applications and Newly Developed Strategies of Solid-Phase Microextraction in Contaminant Analysis: Through the Environment to Humans

The present review aims to describe the recent and most impactful applications in pollutant analysis using solid-phase microextraction (SPME) technology in environmental, food, and bio-clinical analysis. The covered papers were published in the last 5 years (2014–2019) thus providing the reader with information about the current state-of-the-art and the future potential directions of the research in pollutant monitoring using SPME. To this end, we revised the studies focused on the investigation of persistent organic pollutants (POPs), pesticides, and emerging pollutants (EPs) including personal care products (PPCPs), in different environmental, food, and bio-clinical matrices. We especially emphasized the role that SPME is having in contaminant surveys following the path that goes from the environment to humans passing through the food web. Besides, this review covers the last technological developments encompassing the use of novel extraction coatings (e.g., metal-organic frameworks, covalent organic frameworks, PDMS-overcoated fiber), geometries (e.g., Arrow-SPME, multiple monolithic fiber-SPME), approaches (e.g., vacuum and cold fiber SPME), and on-site devices. The applications of SPME hyphenated with ambient mass spectrometry have also been described.

Bio template route for fabrication of a hybrid material composed of hierarchical boehmite, layered double hydroxides (Mg-Al) and porous carbon on a steel fiber for solid phase microextraction of agrochemicals.

Nanosheets of a porous layered double hydroxide were directionally arranged on boehmite nanowires and porous carbon and used as a coating for solid-phase microextraction (SPME) method. Porous carbon tubes were prepared from goat grass and then coated with layered double hydroxide nanosheets and boehmite nanowires. The nanomaterial was placed on a stainless-steel wire which then was used for the extraction of fifteen agrochemicals from aqueous sample solutions. The extraction temperature, extraction time, ionic strength, stirring rate, and desorption temperature and time were optimized. Following thermal desorption of the agrochemicals in the injector of the gas chromatograph, they were quantified by GC/MS. Under optimum conditions, the repeatability for one fiber, expressed as relative standard deviation, was between 2.9 and 11.1%. The detection limits for the agrochemicals are between 2-29 ngL-1. The method is simple, fast, and inexpensive (in terms of equipment). The fiber is thermally stable, and the relative recoveries from spiked samples are better compared to conventional methods of extraction. Graphical abstract Schematic illustration of the preparation of three-dimensional hierarchical boehmite/ layered double hydroxides/ porous carbon (Boeh/LDH/pC) SPME fibers and application for the extraction of fifteen agrochemicals from aqueous sample solutions following quantification by GC/MS.

In situ fabricated porous carbon coating derived from metal-organic frameworks for highly selective solid-phase microextraction

Solid-phase microextraction (SPME) has been widely used in analysis of trace organic contaminants in environmental samples. Stable, efficient, and selective fiber coating is the key to the development of SPME technique. In this study, an in situ fabricated porous carbon coating that derived from metal-organic frameworks (MOFs) was introduced for solid-phase microextraction (SPME). The carbon coating (denoted as MOF-74-C) was prepared by the direct carbonization of a MOF-74 coating that was in situ grown on stainless steel wire, which was explored for the extraction of odorous organic contaminants for the first time. MOF-74-C coated fiber showed high extraction efficiency (1.1–16.0 times larger than commercial fibers for most tested analytes under the same extraction conditions), as well as good thermal and chemical stability. Furthermore, it can selectively extract the analytes with the simultaneous exclusion of coexisting dissolved organic matter due to the molecular sieve effect invoked by the well-defined micropores. The method based on MOF-74-C coating for analysis of odorants afforded wide linear ranges (more than two orders of magnitude), low detection limits (below the odor threshold concentrations), good intra- and inter-day accuracies (90.1–107.3%) and precisions (relative standard deviations/RSDs below 9.4%) and satisfactory reproducibility (RSDs below 8.7%). Finally, the MOF-74-C coated fiber was successfully applied for the SPME analysis of odorants in real water samples. These results highlight the great potential of in situ fabricated porous carbons derived from MOFs for SPME applications.

Application of SPME supported by ionic liquids for the determination of biogenic amines by MEKC in clinical practice

The analysis of biogenic amines (BAs) and their metabolites is helpful for the diagnosis of central nervous system disorders and other neuroendocrine and cancer disturbances. In the study, a developed micellar electrokinetic chromatography method, coupled with diode array detection (MEKC-DAD), was validated to monitor levels of adrenaline (A), noradrenaline (NA), dopamine (DA), L-Tryptophan (L-Tryp) and L-Tyrosine (L-Tyr) in real human urine samples. These neurotransmitters were isolated from urine samples using solid-phase microextraction (SPME) and methanol containing 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid as the desorption phase. The method was linear for DA, A and L-Tyr in the range of 0.5–20 μg/mL and for NA and L-Tryp in the range of 0.25–20 μg/mL. The good linearity for BAs was confirmed by the correlation coefficient (R2) from 0.9989 for A to 0.9997 for NA and L-Tryp, respectively. The validation assays for accuracy, precision, limit of detection, limit of quantification, absolute recovery, and stability of the analytes were consistent with the requirements recommended by the FDA and ICH guidelines. Next, the validated SPME-MEKC method was successfully used for the quantification of A, NA, DA, L-Tryp and L-Tyr in real human urine samples collected from pediatric patients suffering from neuroblastoma, ganglioneuroblastoma, Wilms’ tumor, rhabdoid tumor and lipoblastomatosis, as well as from healthy volunteers. Finally, the levels of BAs in cancer patients were evaluated as to whether they can be used as biomarkers of various health disturbances.