Solid-phase Microextraction Fiber Research Articles

Exhaled Breath Analysis for Assessment of IBD (Inflammatory Bowel Disease) Based on Electronic Nose System

Introduction The diagnosis and differentiation of IBD (Inflammatory Bowel Disease) lacks a single gold standard. IBD commonly suffers from a delay in time from first occurrence of symptoms to diagnosis, especially in young patients with ileal disease, which hinders our ability to alter the progression of disease. Also, once the diagnosis of IBD is made its sub categorization into CD (Crohn’s Disease) or UC (ulcerative colitis) is critical for determining the optimal treatment strategy. It is important to identify at risk population that could benefit from a therapeutic approach [1]. Metabolomics studies have recently enter the field of IBD. A variety of studies have been conducted to be significantly different between CD, UC and heathy controls [2]. Limitation for use of metabolomics markers would be too time-consuming and expensive for assessment of IBD or invasive testing in cases. An ideal approach regarding IBD assessment is that breath metabolome offers great potential with simply, easy to use, non-invasive, cheap, rapid and reproducible [3]. An electronic nose system, which is an instrument comprises an array of chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognition simple or complex odors [4], has been suggested a potential alternative as a novel approach for breath analytic technique.In this presentation, we introduce exhaled breath analysis for assessment of IBD from controls and CD from UC using an electronic nose system incorporating a solid-phase micro extraction (SPME) technique. Method We have been developed an electronic nose system composed one chip type array of chemical sensors, chamber, data acquisition system with microprocessor, and sampling system for SPME fiber operation for non-invasive heath care monitoring. The 2x4 sensor array in the system consisted of three oxides of SnO2, NiO2, and In2O3 using Au, Pt, and Pd as catalyst and fabricated on one chip by glancing angle deposition method [5]. A chamber was used to maintain the stable operating temperature of sensor array, and SPME fiber used transferring of exhaled breath samples for measurement. Figure 1 is shown electronic nose system which has been used for experimental work in the hospital. The collection of exhaled breath for IBD patients (23 CD, 32 UC) and 15 controls was carried out using tedlar bag in connection with mouthpiece having a saliva trap to prevent humidity. The SPME fiber coated 85μm Polyacrylate was inserted into the tedlar bag and exposed to the collected breath at an ambient temperature. The system exposed the fiber to the heated sensor array desorbing the volatile off the fiber directly onto the sensors in the chamber. The collection and measurement of expiration were conducted in a hospital after approval of the IRB (Institutional Review Board) at Dongsan Medical Center, Deagu, Korea. Results and Conclusions The primary result for collected data from electronic nose system is shown at Figure 2 using Linear Discriminant Analysis (LDA) algorithm. As shown in Figure 2, IBD patients and controls are distinguished, especially IBD subgroup between CD and UC is well separated each other. However, some samples from UC subgroup are mixed with controls. In this study, we implemented an electric nose system by fabricating a one chip sensors array incorporating SPME sampling technique. Throughout the experimental result, we investigate the possibility of classification between IBD including 2 subgroup discrimination and controls. However, we need more research to improve discrimination regarding UC and controls following by optimal VOCs markers between UC and control including instrument control.

Flower-like architecture magnesia-carbon composite material for highly sensitive solid-phase microextraction

The development of carbon sorbents with high specific surface areas remains a hot research field in analytical community. In the current study, a novel three-dimensional hierarchical flower-like magnesium glycollate sphere was synthesized. Then, the obtained magnesium glycollate sphere was carbonized to obtain magnesia-carbon composite material with enhanced performance. The flower-like carbon material exhibited good adsorption capacity towards polycyclic aromatic hydrocarbons due to the large surface area, the strong π-π interaction force and hydrophobic forces. The flower-like MgO&C material was used as a solid-phase microextraction fiber coating for the analysis of polycyclic aromatic hydrocarbons in real river water samples. Good linearity (5–1000 ng L−1), satisfactory relatively recoveries (86.2–113.5%) and low limits of detections (0.01–0.20 ng L−1) were obtained under the optimized conditions.

Tuning the extraction properties of ionogel-coated Solid-phase microextraction fibers based on the solvation properties of the ionic liquids

A silica-based network was used to immobilize ionic liquid-based ionogels and applied as a fiber coating for solid-phase microextraction (SPME). The ionogels were prepared by a sol–gel process, using two ionic liquids, triethylsulfonium bis(trifluoromethylsulfonyl)imide ([Set3][TFSI]) and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide ([C4C1Pip][TFSI]), as well as their equimolar mixture. Methyltrimethoxysilane was used as the sol–gel precursor, and trifluoroacetic acid as a reaction catalyst.The fabricated ionogel fibers were evaluated as sorbent coating in headspace SPME combined with gas chromatography with barrier ionization discharge detection for volatile organic compounds (VOCs). The fibers showed a high affinity to aromatic VOCs, yielding good sensitivity and precision. Then, the developed method was applied to the analysis of aqueous samples.During the study, the main extraction parameters, i.e., salt concentration, extraction time, and temperature, were optimized for maximum fiber sorption and to maximize the enrichment factors. The average limits of detection were found to be 0.15 μgL−1, 0.40 μgL−1, and 0.07 μgL−1, and the enrichment factors were in the 25700–61000, 33200–84700, and 29100–96500 ranges for [Set3], [C4C1Pip] and [Set3/C4C1Pip], respectively. The single fiber and fiber-to-fiber reproducibilities were below 11.2% and 30.6%, respectively. The results of this work suggest the possibility of fabricating selected extractants based on the physicochemical properties of the ionic liquids and target analytes.

Rational integration of porous organic polymer and multiwall carbon nanotube for the microextraction of polycyclic aromatic hydrocarbons.

By integration of benzene-constructed porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT), a MWCNT-KBF hybrid material was constructed through in situ knitting benzene with formaldehyde dimethyl acetal inthe presence of MWCNTs to form anetwork. MWCNT-KBF was then adopted as a novel solid-phase microextraction (SPME) fiber coating. Coupled togas chromatography-flame ionization detection, the MWCNT-KBF-assisted SPME method showed large enhancement factors (483-2066), low limits of detection (0.04-0.12μgL-1), good linearity (0.13-50μgL-1), and acceptable reproducibility (4.2-10.2%) for the determination of polycyclic aromatic hydrocarbons (PAHs). The method recoveries of seven PAHs were in the range 80.1-116.3%, with relative standard deviations (RSDs) ranging from 3.5 to 11.9%. The SPME method was successfully applied to the determination of PAHs in river, pond, rain, and waste water, providing a good alternative for monitoring trace level of PAHs in environmental water. Graphical abstract Schematic representation of the rational integration of porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT) to form a MWCNT-KBF hybrid material through in situ knitting benzene with formaldehyde dimethyl acetal at the presence of MWCNT.

Sputtered silicon solid phase microextraction fibers with a polydimethylsiloxane stationary phase with negligible carry-over and phase bleed

We report the preparation of high performance, sputtered, polydimethylsiloxane (PDMS)-coated solid phase microextraction (SPME) fibers that show negligible carry-over and phase bleed. This process involves sputtering silicon onto silica fibers and functionalizing the resulting porous nanostructures with ultrathin films of vapor-deposited PDMS. Different thicknesses of silicon (0.25, 0.8, and 1.8 µm) and PDMS (8, 16, and 36 nm) were produced and their extraction efficiencies evaluated. The deposition of PDMS was confirmed by time-of-fight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), and contact angle goniometry on model, planar silicon substrates. These fibers were investigated using direct immersion SPME coupled with gas chromatography-mass spectrometry (GC–MS) analysis of a series of polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic pollutants. The 1.8 µm thick silicon coating with 16 nm of PDMS (Si (1.8 µm)/PDMS (16 nm)) produced the best response among the combinations tested. Conditions for the extraction of PAHs with this fiber were optimized and its extraction performance was compared to that of a commercial 7 μm PDMS fiber. The linearity (1–110 µgL−1), repeatability (RSD%, n = 3) (17% ave.), and minimum detection limits (0.6–1.5 µgL−1) of the sputtered fibers were determined and found to be superior to the commercial 7 µm PDMS fiber in many respects. Carry-over and phase bleed from commercial PDMS-based SPME fibers are two of their major drawbacks, which decrease their lifetimes and usefulness. Minimal carry-over and phase bleed were observed for our sputtered PDMS-coated fibers. In particular, our fiber only shows 12% of the phase bleed of the comparable commercial fiber. In addition, it shows no carry-over for analytes with retention times greater than pyrene, and only 5% of the carry-over of the other analytes. Our fibers could be used for at least 300 injections without any significant loss of performance.

Identification and evaluation of four cucurbitaceous host plant volatiles attractive to Diaphania indica (Saunders) (Lep.: Pyralidae)

The cucumber moth (CM), Diaphania indica (Saunders) (Lepidoptera: Pyralidae), is a major lepidopteran pest of cucurbitaceous plants that caterpillars feed on vegetative tissue of the plants and thereby cause loss of crops. Previous work has shown that volatile organic compounds (VOCs) released by host plants attract gravid CM females for oviposition, but the compounds responsible for this attraction had not been identified. The purpose of the present study was to identify attractive volatiles/mixtures of components to CM. VOCs from four host plants (cucumber, squash, melon, and watermelon) were collected with solid-phase microextraction fibers and identified by GC–MS. The electroantennography (EAG) response of gravid CM female antennae to host plant VOCs was determined, and also the behavioral responses to selected VOCs were tested in a wind tunnel. From a total of 22 components that were identified, only four (xylene, α-pinene, limonene, and (E)-β-ocimene) were present in all four host plant species. However, these four components seem to play a minor role in CM attraction as shown by EAG and behavioral (wind tunnel) experiments. Benzenoids and terpenoids were the main VOCs for the four host plants. The strongest EAG responses were elicited by four aliphatic compounds ((Z)-6-nonenal, octanal, (E)-2-octen 1-ol, and 1-hexanol) and two benzenoids (benzyl alcohol, and benzaldehyde). In wind tunnel experiments, the most flight responses were recorded for three blends consisting of four compounds [(E, Z)-2,6-nonadienal, (E)-2-nonenal, (Z)-6-nonenal, and 4,8-dimethyl-1,3,7-nonatriene (DMNT)] + (1) benzaldehyde, and benzyl alcohol, (2) β-caryophyllene, and (3) benzyl alcohol. However, only blends composed of (1) benzyl alcohol and DMNT or (2) benzyl alcohol, benzaldehyde, and DMNT elicited landing responses. These findings indicate that mixtures mimicking cucumber volatiles attract gravid CM females, which could in further steps be used to develop lures for control management of CM.

Preparation of hydrophilic molecularly imprinted solid‐phase microextraction fiber for the selective removal and extraction of trace tetracyclines residues in animal derived foods

The present work reported a novel hydrophilic and selective solid-phase microextraction fiber by improved multiple co-polymerization method immobilization of tetracycline molecularly imprinted polymer on a stainless steel wire and directly coupled with high-performance liquid chromatography for sensitive determination of trace tetracyclines residues in animal derived foods. The developed molecularly imprinted polymer coated solid-phase microextraction fibers were characterized through scanning electron microscopy, Fourier transfer infrared spectroscopy, thermogravimetric analysis, and adsorption experiments, the fiber with cross-linked and porous structure was observed and high thermal and chemical stability. The maximum adsorption capacity of this fiber with good selectivity reached 2.35µg/mg in aqueous matrices, and showed good repeatability (relative standard deviation≤6.6%, n=5) and satisfying reproducibility between fiber to fiber (relative standard deviation ≤7.8%, n=5). Under the optimized solid-phase microextraction conditions, satisfactory linearity (5-1000µg/L) and detection limits (0.38-0.72µg/kg, S/N=3) for all the tetracyclines were obtained. The practicality of this method was proved by adding tetracycline, oxytetracycline at three levels to milk, chicken, and fish samples with good recoveries of 77.3-104.4%.

Qualitative analysis of surgical smoke produced during burn operations.

Burned tissue is necrotic and it is surrounded by a zone of stasis and hyperaemia with changed cell metabolism. The removal of burned tissue using an electric knife releases large amounts of surgical smoke. The aim of the research was to analyse volatile, nonpolar, organic compounds that are released during the excision of burned tissue using an electric knife (mono- and bipolar). The study includes analysis from 40 solid-phase microextraction (SPME) fibres, exposed during 10 interventions (6 escharotomy and 4 necrectomy). The analysis of volatile compounds was performed using mass spectrometry gas chromatography (GCxGC-ToFMS).The total analysis covered 432 compounds, whereas after the removal of the "background" compounds - 153 volatile organic substances remained. The analysis of surgical smoke showed that, including derivatives, benzene constituted as much as 17.65% of all of the studied compounds. Cyclic compounds constituted on average 22.5% of the analysed substances, out of which cycloheptatrien constituted 20.26%. Alkanes, alcohols and their derivatives constituted nearly 25% of volatile organic compounds, with chloromethane constituting as much as 13.7%. Permutational multivariate analysis of variance (PERMANOVA) revealed statistically significant differences between escharotomy and necrectomy patients (F(1.9) = 5.91, p = 0.007).Our study revealed the presence of complex toxic hydrocarbon derivatives in surgical smoke. We also observed that the content of surgical smoke is different depending on the type of the conducted intervention. So far, no studies focusing on hazards posed by surgical smoke that is released during the resection of burned tissue are in the literature.

Solid-phase microextraction coatings based on the metal-organic framework ZIF-8: Ensuring stable and reusable fibers

Chemical vapor deposition of MOFs (MOF-CVD) has been used to coat solid-phase microextraction (SPME) fibers with ZIF-8, by exposing ZnO layers to the linker vapor (2-methylimidazole). This ZIF-8 coating has been used as a seed layer in a following solvothermal MOF growth step in order to increase the ZIF-8 thickness. The combined MOF-CVD and solvothermal growth of ZIF-8 on the fibers result in a thickness of ~3 μm, with adequate thermal stability, and mechanical integrity when tested with methanol and acetonitrile ultrasonic treatments. The fibers have been evaluated in direct immersion mode using gas chromatography and flame ionization detection (GC-FID), for a group of target analytes including three polycyclic aromatic hydrocarbons (PAHs) and five personal care products (PCPs). The optimized conditions of the SPME-GC-FID methods include low amount of aqueous sample (5 mL), stirring for 45 min at 35 °C, and desorption at 280 °C for 5 min. The method presents limits of detection down to 0.6 μg L−1; intra-day, inter-day and inter-batch relative standard deviation values lower than 16%, 19%, and 23%, respectively; and a lifetime higher than 70 cycles.

Multitemplate molecularly imprinted polymeric solid-phase microextraction fiber coupled with HPLC for endocrine disruptor analysis in water samples

Molecularly imprinted polymers (MIPs) usually show specific selectivity to a single template molecule and its structural analogs. But how about the selectivity is when multitemplates are used to obtain MIPs? Herein, ethyl p-hydrobenzoate (EP), bisphenol A (BPA) and dibutyl phthalate (DBP) were used as template molecules to synthesize triple-template MIP (TMIP). The adsorption properties of the TMIP for three types of endocrine disruptors (EDCs) in environmental water samples were then examined. For comparison, three single-template molecularly imprinted polymers (SMIPs), three dual-template molecularly imprinted polymers (DMIPs), and a non-imprinted polymer (NIP) were synthesized through the same procedure for TMIP synthesis. DMIP using EP and DBP as templates showed the best selectivity and extraction amounts for EDCs among all MIPs, including TMIP. It was successfully used for EDCs analysis in environmental water samples. The linear range of was 0.1–125 μg L−1. The limit of detection was 0.03 μg•L−1. The recovery ranged from 87% to 120%, and the RSD% (n = 5) was less than 10%. Most importantly in the preparation of multitemplate MIPs, competition was observed between two or more template molecules and the monomer. Therefore, additional template molecules for multitemplate MIPs that do not weaken the previous template-monomer interactions might be considered.

In situ growth of covalent organic framework on titanium fiber for headspace solid-phase microextraction of 11 phthalate esters in vegetables

Vegetables are easily contaminated by phthalate esters (PAEs) from the environment, agricultural films and fertilizers, affecting human health. In this paper, titanium dioxide (TiO2) nanotube arrays were prepared by electrochemical anodic oxidation on the surface of titanium wire. Covalent organic framework of TpBD was in situ bonded to the titanium wire via TiO2 nanotube arrays using monomers of 1,3,5-trimethylphloroglucinol (Tp) and benzidine (BD). The fabricated TpBD-TiO2 coated titanium wire was used as the solid-phase microextraction fiber to extract 11 PAEs in vegetable samples. Coupled with gas chromatography-tandem mass spectrometry (GC–MS/MS), the limits of detection for PAEs were from 0.001 (di-n-butyl phthalate) to 0.430 (butyl benzyl phthalate) μg/L (S/N = 3) and enrichment factors were between 226 (dimethyl phthalate) and 2154 (di-n-butyl phthalate). Our fabricated TpBD-TiO2 fiber can be used at least 150 times without significant loss of extraction efficiency (<4.8%). Quantitative determination of PAEs in vegetable samples (tomato, lettuce, cucumber) was achieved by standard addition.

Phase distribution of polycyclic aromatic hydrocarbons and their oxygenated and nitrated derivatives in the ambient air of a Brazilian urban area☆

Air quality in large cities has worsened in recent years as a consequence people’s health is directly affected. Among the toxic compounds released to environmental air are polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (nitro-PAHs), and oxygenated PAHs (oxy-PAHs). Performant methods to analyze these compounds is necessary to enable adequate monitoring of air quality. Thus, this manuscript presents the development of a highly sensitive method to analyze PAHs, nitro-PAHs, and oxy-PAHs collected from ambient air (PM2.5) and the gas phase for a period of one year in the urban area of Belo Horizonte, Brazil. PAHs and their derivatives were extracted by cold fiber solid phase microextraction (CF-SPME) and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). The proposed method allows simultaneous analysis of 16 PAHs, nitro-PAHs and oxy-PAHs, presenting very good limits of detection and quantification, as well as appropriate precision and recovery. The results obtained for the period of one year allowed different studies. The compounds collected simultaneously from gas and particulate phase showed that total concentration of 16 PAHs were higher in the gas phase than in the particulate. On the other hand, nitro-PAHs and oxy-PAHs presented similar concentration in gas and particulate phases. The potential carcinogenicity of PAHs relative to benzo[a]pyrene showed benzo[a]pyrene equivalents of 0.49 ng m−3. The estimated risk of lifetime lung cancer was 5 × 10−5. Principal component analysis and diagnostic ratio was applied for source distribution indicating that burning of gasoline, diesel and biomass accounted for the PAHs profile in ambient air samples.

A simple strategy based on fibers coated with surfactant-functionalized multiwalled carbon nanotubes to improve the properties of solid-phase microextraction of phenols in aqueous solution

Methods and experimentsIn this study, a functionalized multiwalled carbon nanotube (MWCNT)-coated solid-phase microextraction (SPME) fiber was developed for concentrating analytes in aqueous samples. Sodium deoxycholate (NaDC) was used as a dispersing agent for non-covalent modification of MWCNTs. The coating showed porous structure and large adsorption capacity. To investigate the capability of this MWCNTs/NaDC SPME fiber, it was applied to the analysis of phenols in aqueous solution. After extraction, the analytes were desorbed in an acetonitrile–water solution and analyzed using high-performance liquid chromatography.ResultsThe MWCNTs/NaDC fiber exhibited good analytical performance, and fine preparation reproducibility was obtained with the relative standard deviations (RSDs) ranging from 4.9% to 10.2% (n = 6) in one batch, from 5.7% to 11.9% (n = 3) among different batches. Under the optimum extraction conditions, the detection limits were 0.15–0.30 ng/mL(S/N = 3), the linear detection ranges were 1–100 ng/mL (R2 ≥ 0.9997) for these analytes, and good recoveries (80.3–95.4%) were obtained for the spiked samples.ConclusionThis is a simple and accurate pretreatment method for the analysis of phenols in aqueous samples.

Flower-like layered double hydroxide-modified stainless-steel fibers for online in-tube solid-phase microextraction of Sudan dyes.

Layered double hydroxides are a family of inorganic crystals that have gained a lot of attention due to its special structure and properties such as high porosity, large specific area, and excellent anion exchange ability. In this work, flower-like NiAl-layered double hydroxides with high specific area were in situ immobilized onto the stainless steel fibers by bioinspired polydopamine modification method and packed into poly (ether ether) ketone tube for online solid-phase microextraction with high performance liquid chromatography analysis. Thanks to the high specific surface area and excellent extraction ability of the NiAl-layered double hydroxides, the fibers showed excellent extraction performance to three Sudan dyes with enrichment factors between 260 to 650 folds. After optimization of the reaction and extraction conditions, an online solid-phase microextraction method was developed for determination of Sudan dyes in water samples and chili samples. The method has limits of detection of 0.01 to 0.02ng/mL, good linearity and good reproducibility (≤1.45%).

Interface for Reproducible, Multishot Direct Analysis of Solid-Phase Microextraction Samples.

An enclosed interface that joins a direct analysis in real time (DART) probe, solid-phase microextraction (SPME) fiber, and the inlet of a high-resolution mass spectrometer is described. Unlike other systems to couple SPME sampling to ambient mass spectrometry, the interface is able to perform discrete analyses on different areas of a single SPME fiber device for up to three technical replicate measurements of one sampling event. Inlet flow speed and desorption temperature are optimized, and reproducibility is demonstrated between replicate analyses on the same derivatized SPME fiber and with sequential fiber sampling events, yielding analyte measurement center of variance (CV) from 3 to 6%. Conditioning is also performed with the enclosed DART. The interface is a straightforward addition to commercially available technologies, and machine diagrams for custom components operated with SPME/DART/MS equipment are included.

Hollow fiber-solid phase microextraction of phthalate esters from bottled water followed by flash evaporation gas chromatography-flame ionization detection

A solid phase microextraction coupled with flash evaporation gas chromatography method was applied to the determination of phthalate esters (PAEs). Polysulfone (PSF) hollow fiber at 1 cm length was employed as extraction element to adsorb PAEs directly. Predominant parameters including stirring velocity, salt concentration, extraction time and extraction temperature were optimized. PSF fiber with absorbed PAEs was put into a small sample cup. The extracted analytes were thermally desorbed at 300 °C in a pyrolyzer, and then entered into a column for separation. The linearity of the method was satisfactory over a concentration range of 2–1000 µg/L with the correlation coefficients r>0.99 for all analytes except dimethoxyethyl phthalate. The relative standard deviations for peak areas were below 9.5% (n = 6). The developed technique achieved high enrichment factors (280–9930 times) and low limits of detection (0.001–0.130 µg/L). The recoveries over the range of 87.0–117.7% were obtained by analyzing real spiked samples. The results demonstrated that this was a simple, environmentally friendly and accurate method for the determination of PAEs in bottled water samples.

Fabrication of Solid Phase Microextraction Fibers of Titanium Wires and Its Application

Fabrication of Solid Phase Microextraction Fibers of Titanium Wires and Its Application

Design and optimization of the VA-TV-SPME method for ultrasensitive determination of the PAHs in polluted water

This paper describes how a novel and reliable alternative approach was developed for conventional solid-phase microextraction (SPME) sampling by total-vaporization of a sample under vacuum conditions. SPME sampling consists two stages of the equilibrium process, which take place between the sample/headspace and the headspace/fiber coating. In the total-vaporization SPME (TV-SPME) strategy, the first stage is omitted and analytes are directly partitioned between the headspace and fiber coating. In this research, the TV-SPME strategy was implemented by the extraction of PAHs from aqueous media, using a polydimethylsiloxane (PDMS) coated SPME fiber. The most important variables were investigated and optimized. Optimal conditions were obtained at an extraction temperature of 55 °C, a vaporization time of 25 min, and a sample volume of 100 μL. To achieve higher sensitivities in shorter times, the TV-SPME setup was coupled with the VA-SPME system, which resulted in a much lower extraction temperature and time, in comparison with the conventional TV-SPME method. Under optimal experimental conditions, the calibration curves were linear across the area of 0.015–2 μg mL−1 (R2 > 0.996). The limits of detection (LODs) were obtained in the range of 0.3–5 ng mL−1, and the relative standard deviations (RSDs, n = 6) were 6.1–7.5%. The developed vacuum-assisted total-vaporization SPME (VA-TV-SPME) technique, was coupled with GC-FID and successfully utilized for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples. The data obtained was statistically in accordance with that achieved employing a validated approved method.

Determination of Volatile Water Pollutants Using Cross-Linked Polymeric Ionic Liquid as Solid Phase Micro-Extraction Coatings.

Ionic liquids found a wide application in catalysis and extraction due to their unique properties. Herein, ethylene glycol dimethacrylate as the cross-linker and 1-vinyl-3- butylimidazolium tetrafluoroborate as functional monomer via thermally initiated free-radical polymerization was prepared as a novel copolymer solid phase micro-extraction (SPME) coating. A surface modified stainless-steel wire was implemented as the substrate. Factors affecting the extraction performances of the copolymer, including the molar ratio of monomers to cross-linkers, the amount of porogen agent, and polymerization time were evaluated and optimized. To evaluate the extraction performance, five commonly seen polycyclic aromatic hydrocarbons (PAHs) were taken as the analytical targets. The potential factors affecting extraction efficiency were optimized. The as-prepared SPME device, coupled with gas chromatography, was successfully applied for the determination of PAHs in water samples. The wide linear range, low detection limit, good reproducibility, selectivity, and excellent thermal stability indicate the promising application of the newly developed SPME fiber in environmental monitoring as well as in other samples having complex matrices.

Accordion-like Ti3C2Tx MXene nanosheets as a high-performance solid phase microextraction adsorbent for determination of polycyclic aromatic hydrocarbons using GC-MS.

Two dimensional accordion-like Ti3C2Tx MXene, where Tx represents surface termination groups such as -OH, -O-, and -F, is synthesized by selective etching of aluminum layers from Ti3AlC2. This manuscript reports on the adsorption of organic molecules from head-space and aqueous environments containing Ti3C2Tx, a representative of the MXene family. Ti3C2Tx coated by gluing method on a stainless steel wire was successfully utilized as a highly sensitive and stable head-space solid-phase microextraction (SPME) fiber. A SPME method with the MXene as the adsorbent combined with gas chromatography with MS detector was used to determine the polycyclic aromatic hydrocarbons (PAHs) in water samples. Low detection limits in the range of 0.2-5ngL-1, wide linearity and good reproducibility (RSD = 4.6 to 7.4% for n= 6) under the optimized extraction conditions was achieved. Finally, the MXene coated fiber was successfully used for the determination of PAHs in real water samples. The relative recoveries for six PAHs are from 91.3-105.0%, which proved the applicability of the method. Also, melamine was selected as a polar analyte and it has been shown that Ti3C2Tx MXene has good capability in extraction of melamine (the extraction recovery for melamine = 80.1%) from aqueous media by dispersive micro solid-phase extraction. Graphical abstractTwo dimensional accordion-like Ti3C2 MXene was synthesized by selective etching of aluminum layers from Ti3AlC2. Ti3C2 MXene was employed as solid phase microextraction fiber coating for the extraction of polycyclic aromatic hydrocarbons from water samples.