Solid-phase Microextraction Fiber Research Articles

Hybrid ZIF-8-90 for Selective Solid-Phase Microextraction of Exhaled Breath from Gastric Cancer Patients.

Metal-organic frameworks (MOFs) are a new kind of microporous materials whose unique properties make them promising as coatings for solid phase microextraction (SPME). However, previous MOF coatings for SPME exclusively focus on single-linker MOFs, and the selective enrichment of polar or nonpolar targets depends on the polarity of linker on the surface of MOFs, which greatly limits the application of MOF coating for SPME in real samples. Here, we report a hybrid MOF-coated stainless steel fiber for SPME of biomarkers in exhaled breath from gastric cancer patients. Zeolitic imidazolate framework-8-90 (ZIF-8-90) possesses the aldehyde groups and methyl groups in the framework as a model MOF, and eight biomarkers (ethanol, acetone, hexanal, hexanol, nonane, isoprene, heptane, and decane) were used as the target analytes. The ZIF-8-90-coated fiber shows high enrichment efficiency for hydrophilic targets and hydrophobic targets, wide linearity (three orders of magnitude), and low detection limits (0.82-2.64 μg L-1). The ZIF-8-90-coated fiber exhibited higher enrichment performance for all the investigated analytes as a result of the synergy of methyl and aldehyde groups, the porous structure, and the suitable pore size of ZIF-8-90 (4-5 Å). The relative standard deviation (RSD) of six repetitions for extractions using the same ZIF-8-90-coated fiber ranged from 2.5 to 7.3%. The reproducibility between the three fibers prepared in parallel varied in the range of 4.8-12% (RSD). The fabricated ZIF-8-90-coated fiber lasted for at least 120 cycles of extraction/desorption/conditioning without an obvious reduction in extraction efficiency and precision. Finally, the developed ZIF-8-90-coated SPME fiber has been successfully used for the analysis of exhaled breath samples from gastric patients with satisfied recoveries (88-106%).

Preparation of covalent organic framework based on room temperature solution-suspension approach and its application to solid-phase microextraction of pyrethroids in tea

拟除虫菊酯(PYs)类农药被广泛用于茶园病虫害的防治。随着国内外对进出口茶叶中农药残留限量的要求日益严格,我国迫切地需要开发能应用于检测茶叶中痕量PYs的方法。研究通过简单、温和的溶液悬浮法(SSA),在室温下制备了共价有机骨架(COF)材料TpBD,该材料具有优异的热/化学稳定性、较高的孔隙度和比表面积。通过简单物理黏附的方法,将TpBD制备成固相微萃取(SPME)纤维。将准备好的纤维应用于固相微萃取技术并与气相色谱-串联质谱(GC-MS/MS)联用,建立用于检测PYs的高灵敏分析方法。该方法对氟氯氰菊酯、氯氰菊酯、氟氰菊酯、氰戊菊酯和溴氰菊酯的富集倍数为702~2687,并表现出低的检出限(0.1~0.5 ng/L)、宽的线性范围(0.2~800 ng/L)、良好的线性关系(相关系数≥0.9991)、可接受的重复性(RSD≤11.0%, n=3)。将所建立的方法用于实际绿茶和乌龙茶样品中PYs残留量的检测,并成功地从实际茶样中检测出5种痕量PYs,并且具有满意的回收率(80.2%~109.5%)。实验结果表明,所建立的分析方法适用于茶叶中PYs农药残留量的分析和检测。此外,通过SSA成功地制备了TpBD材料,证实了该方法具有较好的普适性,具有简便合成其他COFs材料的潜力。

Assessment of polycyclic aromatic hydrocarbons and derivatives in beer using a new cold fiber-solid phase microextraction system

Sample preparation assisted by a cooling system including solid phase microextraction (SPME) has received an increased interest in recent years. In this work, a new cold fiber (CF-SPME) system using thermoelectric cooling is proposed. The system consists of three thermoelectric coolers (Peltier), a heat sink, a recirculation module to dissipate the heat generated on the hot side, and an electric power source to generate the necessary voltage for the system. The Peltier keeps the SPME fiber cool during the extraction process.. This system was used to analyze polycyclic aromatic hydrocarbons (PAHs), and their nitrated (nitro-PAHs) and oxygenated (oxy-PAHs) derivatives, in commercial beers by gas chromatography coupled to mass spectrometry (GC/MS). The analyte's extraction was optimized through Doehlert design. Optimal extraction conditions were obtained with a salt content of 0.6% w/v and beer volume of 700.0 μL. The validated method showed limits of detection (LOD) in the range of 0.003–0.128 μg L−1 and limits of quantification (LOQ) from 0.011 to 0.427 μg L−1. Precision Coefficients of Variation values ranged from 3.0 to 18.7%, and recovery values of the analytes in beer varied between 80.1 and 100.3%. Among the PAHs derivatives evaluated in this study, only 9-fluorenone and 9-nitroanthracene were detected in some samples. Benzo[b]fluoranthene was the most detected analyte in the samples, and at least one PAH was detected in all samples. Principal component analysis (PCA) separated the samples into two groups, mainly due to the high relative concentrations of acenaphthene and chrysene. The cooling approach improved the extraction efficiency and the new system demonstrated high potential for portability and automation.

Recent Applications of Solid Phase Microextraction Coupled to Liquid Chromatography

Solid phase microextraction (SPME) is one of the most popular sample preparation methods which can be applied to organic compounds allowing the simultaneous extraction and pre-concentration of analytes from the sample matrix. It is based on the partitioning of the analyte between the extracting phase, generally immobilized on a fiber substrate, and the matrix (water, air, etc.), and has numerous advantages such as rapidity, simplicity, low cost, ease of use and automation, and absence of toxic solvents. Fiber SPME has been widely used in combination with various analytical instrumentation even if most of the work has been done coupling the extraction technique with gas and liquid chromatography (GC and LC). This manuscript presents an overview of the recent works (from 2010 to date) of solid phase microextraction coupled to liquid chromatography (SPME-LC) relevant to analytical applications performed using commercially available fibers or lab-made fibers already developed in previous papers, and to improved instrumental systems and approaches.

Oxygenated carbon nanotubes cages coated solid-phase microextraction fiber for selective extraction of migrated aromatic amines from food contact materials

In this study, an oxygenated carbon nanotubes cages (OCNTCs) material was prepared by calcinating zeolitic imidazole framework-67 (ZIF-67) and then oxidizing the resulting material. The OCNTCs was used as a high efficient solid-phase microextraction (SPME) coating to extract aromatic amines (AAs). The obtained fiber exhibited high selectivity for AAs over other organic compounds in food contact materials (FCMs) due to matched pore size and abundant oxygen-containing groups. Subsequently, coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS), a sensitive method with low limits of detection (0.1-2.0 ng L−1), wide linear ranges (0.5-500 ng L −1) and good precision (RSDs ≤ 8.6%) was developed for analysis of AAs. The specific migrated AAs from food simulants that prepared by standardized migration and thermal migration test were successfully analysed by this developed method with satisfactory recoveries (81.6% - 118.1%) and precision (RSDs, 2.1-9.5%). The results demonstrated that the prepared OCNTCs-coated fibers displayed excellent extraction performance, suggesting a promising application to investigate the migration behaviors of AAs.

Preparation and application of lysozyme aptamer fibre for specific recognition of lysozyme in food samples

A novel aptamer solid-phase microextraction (SPME) fibre-based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) for lysozyme-specific recognition has been successfully prepared. The prepared SPME fibres were characterised by various instrumental methods, including scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectrometry. The results showed that the SPME fibre exhibited a porous structure, which is beneficial for the enrichment of the aptamer. The solid-phase microextraction-high-performance liquid chromatography-fluorescence detection (SPME-HPLC-FLD) with the superior selectivity and sensitivity responded linearly to the concentration of lysozyme over the 0.025–10 mg/L range, and the limit of detection was low at 6.8 μg/L, with a linearity of 0.9995. The method showed excellent reproducibility, and the relative standard deviations (RSDs) were less than 5.5%, which facilitated the analysis. The method was applied for the analysis of lysozyme in cow milk and papaya samples, and the recoveries ranged from 86.7–93.5% with RSDs of 4.3–6.1%, which clearly state that the proposed lysozyme aptamer SPME-HPLC-FLD method is a promising analytical tool for the analysis of lysozyme in food samples.

Poly(ionic liquid)-hybridized silica aerogel for solid-phase microextraction of polycyclic aromatic hydrocarbons prior to gas chromatography-flame ionization detection

Using poly(ionic liquid) (PIL) and tetraethyl orthosilicate (TEOS) as the co-precursors, PIL-hybridized silica aerogel was prepared via sol-gel method for solid-phase microextraction (SPME). The ratio between PIL and TEOS was regulated to achieve the best extraction effect. The aerogel was coated onto the surface of stainless steel wire to get SPME fiber. Coupled to gas chromatography-flame ionization detector (GC-FID), the fiber was separately evaluated by the determination ofalkanes, polycyclic aromatic hydrocarbons (PAHs), as well as BTEX (benzene, toluene, ethylbenzene, and xylenes) in immersion mode. The extraction performance of PAHs was attributed to π stacking and hydrophobic effect. After optimization of main extraction and desorption conditions, the SPME-GC-FID method was establishedtowards eight PAHs, and it provided low detection limits (0.005μgL-1, 0.010μgL-1) and wide linear ranges (0.016-20.00μgL-1, 0.033-20.00μgL-1) with good linear coefficients (0.9991-0.9998). The method was applied to detect trace PAHs in real water samples, with relative recoveries of 86.2-119.2%. Furthermore, PIL-hybridized silica aerogel exhibits some superiorities like higher sensitivity, shorter extraction time, and better repeatability over other extraction coatings. The present work not only extends the range of aerogel materials but also promoted their further applications in sample preparation. Graphical abstract.

Polyaniline/titanium dioxide nanorods functionalized carbon fibers for in-tube solid-phase microextraction of phthalate esters prior to high performance liquid chromatography-diode array detection

To improve extraction performance of carbon fibers (CFs) towards phthalate esters (PAEs), titanium dioxide (TiO2) nanorods array was in-situ grown on the surface of CFs, then polyaniline (PANI) was used to modify it. PANI/TiO2 nanorods-CFs were placed into a polyetheretherketone tube for solid-phase microextraction (SPME). Combining the tube to high performance liquid chromatography (HPLC), it was evaluated and displayed good extraction performance for several PAEs. Compared with bare CFs, TiO2 nanorods and PANI, PANI/TiO2 nanorods presented best performance, attributed to the unique advantages between high surface area of TiO2 nanorods and multiple adsorption interactions (like π-π stacking, hydrogen bond) of PANI. After the optimization of the important factors (sampling volume, sampling rate, sample pH, concentrations of organic solvent and salt in sample, and desorption time), the online in-tube SPME-HPLC method was established. It provided low limits of detection (0.01-0.05 μg L−1) and wide linear ranges (0.03-30, 0.10-30, 0.17-30 μg L−1) with correlation coefficients larger than 0.9991. The relative standard deviations (n=6) between intra-day and inter-day tests were in the ranges of 3.5-10.3% and 4.7-13.9%, respectively. The method was successfully used to determine seven PAEs in real water samples. Besides of satisfactory durability, the material also exhibited superior extraction performance than some materials.

In-situ synthesis of nanocubic cobalt oxide @ graphene oxide nanocomposite reinforced hollow fiber-solid phase microextraction for enrichment of non-steroidal anti-inflammatory drugs from human urine prior to their quantification via high-performance liquid chromatography-ultraviolet detection

The in-situ synthesis and application of nanocubic Co3O4-coated graphene oxide (Co3O4@ GO) was introduced for the first time to present a cost-effective, stable and convenient operation and a simple device for hollow fiber solid-phase microextraction (HF-SPME) of four selected nonsteroidal anti-inflammatory drugs (NSAIDs) including diclofenac, mefenamic acid, ibuprofen and indomethacin. The extracted analytes were desorbed by an appropriate organic solvent and analyzed via high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The prepared sorbent was approved using different characterization methods such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The variables effective on the Co3O4@GO-HF-SPME method including extraction time, desorption time, desorption solvent volume, sample pH, stirring rate and ionic strength were screened via Plackett–Burman design and then optimized by Box–Behnken design. Under optimal condition, the calibration curves were linear within the range of 1.0–200.0 µg L−1 of analyte concentration with detection limits of 0.18–1.1 µg L−1 and the relative standard deviations less than 10.1%. The limits of quantification (LOQs) were in the range of 0.60–3.67 µg L−1. Matrix effect was not observed with this method; therefore, standard addition is not necessary for quantification of target compounds. The enrichment factors were obtained in the range of 49–68. The relative recoveries of the urine sample analysis were calculated in the range of 93–102%. Finally, the presented method exhibited good sensitivity, excellent repeatability, high reusability and acceptable precision, which will be a promising method to analyze various nonsteroidal anti-inflammatory drugs in urine samples.

Selectively Determination Trace Amounts of Polycyclic Aromatic Hydrocarbons from Water and Wastewater Matrices Using Graphitic Carbon Nitride/Layered Double Hydroxide Nanocomposite on Porous Anodized Aluminum Wire as SPME Fiber

Synthesis a well-suited coating for solid phase microextraction (SPME) fiber is essential point due to determination trace amounts of analytes from water and wastewater samples. So, the new coating was built onto the porous anodized aluminum wire incorporated with layered double hydroxide compound and modified solvothermally with graphitic carbon nitride and used as fiber coating for selectively analysis of polycyclic aromatic hydrocarbons by HS-SPME method. According to the results, this coating indicated considerable potential due to extract simultaneously trace amounts of some carcinogenic polycyclic aromatic compounds in different matrices. Essential parameters such as microextraction time, microextraction temperature, agitation speed and ionic strength of the sample solution that mainly affect the adsorption process were optimized and in the optimum values, repeatability data of one fiber that changed between 4.7% and 7.7% for the test compounds were achieved. Detection limits for the studied compounds were between 0.002 to 0.32 µg L−1. It is a simple, quick, and cheap approach. There is stability in the fiber in terms of temperature, and great recoveries are obtained by its use.

Fabric Phase Sorptive Extraction: A Paradigm Shift Approach in Analytical and Bioanalytical Sample Preparation.

Fabric phase sorptive extraction (FPSE) is an evolutionary sample preparation approach which was introduced in 2014, meeting all green analytical chemistry (GAC) requirements by implementing a natural or synthetic permeable and flexible fabric substrate to host a chemically coated sol–gel organic–inorganic hybrid sorbent in the form of an ultra-thin coating. This construction results in a versatile, fast, and sensitive micro-extraction device. The user-friendly FPSE membrane allows direct extraction of analytes with no sample modification, thus eliminating/minimizing the sample pre-treatment steps, which are not only time consuming, but are also considered the primary source of major analyte loss. Sol–gel sorbent-coated FPSE membranes possess high chemical, solvent, and thermal stability due to the strong covalent bonding between the fabric substrate and the sol–gel sorbent coating. Subsequent to the extraction on FPSE membrane, a wide range of organic solvents can be used in a small volume to exhaustively back-extract the analytes after FPSE process, leading to a high preconcentration factor. In most cases, no solvent evaporation and sample reconstitution are necessary. In addition to the extensive simplification of the sample preparation workflow, FPSE has also innovatively combined the extraction principle of two major, yet competing sample preparation techniques: solid phase extraction (SPE) with its characteristic exhaustive extraction, and solid phase microextraction (SPME) with its characteristic equilibrium driven extraction mechanism. Furthermore, FPSE has offered the most comprehensive cache of sorbent chemistry by successfully combining almost all of the sorbents traditionally used exclusively in either SPE or in SPME. FPSE is the first sample preparation technique to exploit the substrate surface chemistry that complements the overall selectivity and the extraction efficiency of the device. As such, FPSE indeed represents a paradigm shift approach in analytical/bioanalytical sample preparation. Furthermore, an FPSE membrane can be used as an SPME fiber or as an SPE disk for sample preparation, owing to its special geometric advantage. So far, FPSE has overwhelmingly attracted the interest of the separation scientist community, and many analytical scientists have been developing new methodologies by implementing this cutting-edge technique for the extraction and determination of many analytes at their trace and ultra-trace level concentrations in environmental samples as well as in food, pharmaceutical, and biological samples. FPSE offers a total sample preparation solution by providing neutral, cation exchanger, anion exchanger, mixed mode cation exchanger, mixed mode anion exchanger, zwitterionic, and mixed mode zwitterionic sorbents to deal with any analyte regardless of its polarity, ionic state, or the sample matrix where it resides. Herein we present the theoretical background, synthesis, mechanisms of extraction and desorption, the types of sorbents, and the main applications of FPSE so far according to different sample categories, and to briefly show the progress, advantages, and the main principles of the proposed technique.

Novel polyphenol/graphene nanocomposite for solid-phase microextraction of bisphenol A and bisphenol B leached from plastic containers

A pioneer solid-phase microextraction (SPME) fiber including polyphenol (PPh) and graphene oxide nanosheets (GONSs) was set up electrochemically on copper wire. Thereafter this nanocomposite was applied to preconcentration of bisphenol A and bisphenol B leached from plastic containers followed by gas chromatography-mass spectrometry determination. Effect of different electropolymerization items were herein evaluated and optimized. Characterization of surface morphology, chemical structure and thermostability of the as-prepared PPh/ GONSs nanocomposite was executed. Various parameters relating to the extraction and preconcentration of the analytes were considered in details. Under the optimized conditions, wide linear range (0.1−100.0 ng mL−1) and low detection limits (0.02 and 0.04 ng mL−1) were attained for both analytes. Also, Good repeatability using a single fiber and acceptable fiber-to-fiber reproducibility using three fibers were achieved. Finally, in accuracy tests on real samples, high recoveries were acquired.

Development and comparison of direct immersion solid phase micro extraction Arrow-GC-MS for the determination of selected pesticides in water

Pesticides are compounds which can affect human, environmental and aquatic system health. Therefore, the detection and determination of these compounds at trace level concentrations is of great importance. In this study selected pesticides out of four classes were investigated as target analytes: Dichlorovos as an insecticide, terbutryn as herbicide, cybutryne from the group of biocides and quinoxyfen as an example of fungicides. A direct immersion solid phase micro extraction (SPME) Arrow-GC–MS method was developed and validated for fully automated microextraction of the target compounds from aqueous samples. In this regard, the most important experimental parameters of the extraction: Extraction time, extraction temperature, pH, ionic strength of the sample and the Arrow type, were studied and optimized. In addition, the developed method was compared with the conventional SPME, regarding sensitivity, relative recovery and precision. The limit of detection values of SPME Arrow were between 0.68 and 544 ng L-1 for dichlorvos and quioxyfen, respectively, and significantly less than similar values obtained from conventional SPME (4.63 and 4400 ng L-1 for the same compounds). For all investigated pesticides, recovery rates ranged between 90 and 116% for the Arrow as well as 85 and 107% for the classical SPME fiber. Relative standard deviations (RSD %) were 4.3–7.8 and 3.5–11.8 for the Arrow and classic SPME, respectively. Also, coefficient of determination (R2) range was within the range of 0.993–0.999 for SPME Arrow and 0.990–0.996 for classic SPME.

Synthesis and application progress of covalent organic polymers in sample preparation for food safety analysis

食品安全关系身体健康和生命安全,是全球关注的热点之一。食品基质复杂,痕量有毒有害物质分析之前必须经过有效的前处理。目前发展的前处理技术如固相萃取、磁固相萃取、固相微萃取等,其关键是吸附介质。共价有机聚合物是一类通过共价键连接而成的有机多孔材料,具有质轻、稳定性好、比表面积大、结构可控、易于修饰等特性,是一类优异的新型吸附材料。该文综述了近年来共价有机聚合物(COPs)在食品安全分析前处理中的应用进展。共价有机聚合物及其功能化复合材料通过简单的装填、聚合反应或化学键合固定到小柱或毛细管柱中用作固相萃取的吸附介质;通过一锅法、原位还原法、原位生长法或共沉淀法生成具有磁性的固相萃取吸附介质;或者通过物理涂覆、化学键合、溶胶凝胶法及原位生长法制备固相微萃取纤维。基于以上高吸附容量共价有机聚合物的样品前处理技术,食品中农残兽残、添加剂、环境污染物及生物毒素等得到了有效富集。最后,展望了COPs在食品分析样品前处理应用中的发展方向:简单高效绿色制备方法的开发,功能化COPs的设计合成;萃取机理的研究;高通量、高灵敏度分析方法研究。这些研究将促进COPs在样品前处理领域获得更广泛的应用。

Hierarchically Synthesis of Nanoflower Layered Double Hydroxide/Molybdenum Disulfide on Electrochemically Anodized HB Pencil Lead for Determination Trace Amounts of Polycyclic Aromatic Hydrocarbons

Preparation coating materials is a fundamental point in solid-phase microextraction (SPME) fiber fabrications. So, a hydrothermal approach was developed for fabricating 3 D hierarchically molybdenum disulfide/layered double hydroxide on anodized HB pencil lead, Nanosheets of a porous molybdenum disulfide and layered double hydroxide were directionally arranged on anodized HB pencil lead and used as a fiber coating for selectively analysis of polycyclic aromatic compounds (PAHs) by headspace SPME method. The as-synthesized materials were characterized by thermal gravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, According to the results, this coating indicated considerable potential due to extracting trace amounts of some carcinogenic polycyclic aromatic compounds in water samples. The essential parameters such as extraction time, extraction temperature, agitation speed, and ionic strength of sample that mainly affect the adsorption process were optimized and in optimum values, the repeatabilities for one fiber were between 4.6% and 9.1% for the test compounds were achieved. The studied compounds were assessed within the detection limits as follows: 0.028 to 0.42 ngL−1.

Fabrication of Co3O4 quantum dot incorporated polyacrylamide ethylene glycol dimethacrylate as a new fiber for solid phase microextraction and trace determination of organophosphorus pesticides in environmental water samples.

In this paper, a novel solid phase microextraction fiber based on Co3O4 quantum dot incorporated polyacrylamide-co-ethylene glycol dimethacrylate followed by corona discharge ion mobility spectrometry is presented for the trace determination of organophosphorus pesticides in environmental water samples. Ion mobility spectrometry is a comparatively inexpensive, well-known, robust, and easy to operate analytical instrument. This combination would provide a low-cost, fast, selective, and sensitive quantitative system for detection of organophosphorus pesticides. In order to obtain the best extraction efficiency, the optimization of parameters affecting this method was carried out. After optimization, a solution pH of 7.0, extraction temperature of 60 °C, adsorption temperature of 260 °C, extraction time of 30 min, stirring speed of 750 rpm, and ionic strength of 10% w/w were obtained. Consequently, the presented method showed low limits of detection (0.3-0.6 ng mL-1), excellent enrichment factors (PF = 221-263), good linearity (R2 > 0.995), and repeatabilities (intra-day: 3.4 to 4.8%) and (inter-day: 4.7 to 6.1%). The reproducibility (RSD% of fiber to fiber) was also investigated by analyzing three as-prepared fibers under the same conditions and was found to be less than 7.6%. Finally, the developed fiber was used for determination of organophosphorus pesticides in the field samples.

Novel copper sulfide doped titania nanoparticles as a robust fiber coating for solid-phase microextraction for determination of polycyclic aromatic hydrocarbons

Immobilized TiO2 nanoparticles modified by nanoscale CuS (CuS@TiO2NPs) were successfully synthesized and used as fibers for solid-phase microextraction (SPME) for the determination of some polycyclic aromatic hydrocarbons (PAHs) in water samples. A novel fiber has been developed by postprecipitation of CuS coated the titania nanoparticles in situ grown on a titanium wire annealed at 550 °C in a nitrogen ambient atmosphere. Its morphology and surface properties were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. It was connected to high performance liquid chromatography-ultraviolet detector (HPLC-UV) equipment by replacing the sample loop of a six-port injection valve, building the online SPME-HPLC-UV system. Variables affecting extraction procedures, including desorption time, stirring speed, extraction temperature, extraction time and ionic strength were investigated and the parameters were optimized. The SPME fiber exhibits high selectivity for the five PAHs studied. The linear ranges varied between 0.15 μg L−1 and 200 μg L−1 with correlation coefficients ranging from 0.9913 to 0.9985. LODs and LOQs ranged from 0.02–0.04 μg L−1 and 0.07–0.13 μg L−1. RSDs for one fiber and fiber-to-fiber were in the range of 3.2–4.3% and 4.6–6.8%, respectively. Additionally, the fiber possessed advantages such as resistance to organic solvent, high mechanical strength and difficult breakage, making it have strong potential applications in the selective extraction of PAHs from complex water samples at trace levels.

High-efficiency solid-phase microextraction performance of polypyrrole enhanced titania nanoparticles for sensitive determination of polar chlorophenols and triclosan in environmental water samples.

In this work, a polypyrrole (PPy)/TiO2 nanocomposite coating was fabricated by the direct electropolymerization of pyrrole on annealed TiO2 nanoparticles and evaluated as a novel direct immersion solid phase microextraction (DI-SPME) fiber coating for extraction of trace amounts of pollutants in environmental water samples. The functionalized fiber is mechanically and chemically stable, and can be easily prepared in a highly reproducible manner. The effects of the pyrrole monomer concentration, polymerization voltage and polymerization time on the fiber were discussed. Surface morphological and compositional analyses revealed that the composite coating of nano polypyrrole and titanium dioxide nanoparticles (TiO2NPs) uniformly doped the Ti substrate. The as-fabricated fiber exhibited good extraction capability for phenolic compounds in combination with high performance liquid chromatography-UV detection (HPLC-UV). At the optimum SPME conditions, the calibration curves were linear (R2 ≥ 0.9965). LODs and LOQs of less than 0.026 μg L−1 and 0.09 μg L−1 , respectively, were achieved, and RSDs were in the range 3.5–7.2%. The results obtained in this work suggest that PPy/TiO2 is a promising coating material for future applications of SPME and related sample preparation techniques.

Carbon aerogel as a solid-phase microextraction fiber coating for the extraction and detection of trace tetracycline residues in food by coupling with high-performance liquid chromatography.

A direct immersion solid-phase microextraction method for determining tetracyclines (TCs) was developed by coupling with high-performance liquid chromatography. A carbon aerogel (CA) was synthesized as a fiber coating with high extractive properties and a low density of 0.1855 g cm-3via ambient pressure drying and carbonization. The as-synthesized CA exhibited a high specific surface area and a cross-linked structure; it was characterized via scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analysis, etc. The extraction performance for six TCs was investigated, and the main experimental parameters were optimized by the Box-Behnken design. Adsorption kinetics, Langmuir and Freundlich models were used to clarify the extraction mechanism. This method showed wide linear ranges of 1-500 μg L-1, low limits of detection of 0.52-1.05 μg L-1, good repeatability of 1.37-12.47%, and satisfactory inter-fiber reproducibility of 8.51-15.81% relative standard deviation for the detection of six TCs. Moreover, this study provided an interesting insight into the detection of TCs residues in food samples.

Derivation of carbonaceous nanoparticles from glucose-modified nickel-titanium oxide nanoparticles grown on Nitinol fiber for solid phase microextraction of several polycyclic aromatic hydrocarbons in water samples

A facile strategy was developed for the fabrication of new nanoparticles-templated carbonaceous coating on a Nitinol (NiTi) fiber substrate. The NiTi fiber was first electrochemically anodized for the growth of nickel-titanium oxide nanoparticles (NiTiONPs). Thereafter, NiTiONPs were used as supporting templates for the derivation of carbonaceous nanoparticles (CNPs) via the hydrothermal reaction of glucose followed by carbonization in nitrogen atmosphere. The adsorption performance of the NiTi@NiTiONPs and the NiTi@NiTiO@CNPs fibers was evaluated using typical aromatic compounds as model analytes coupled to high-performance liquid chromatography with UV detection. The results clearly indicated that the NiTiO@CNPs coating exhibited higher extraction capability for polycyclic aromatic hydrocarbons (PAHs) than UV filters. For this purpose, several parameters of SPME with the NiTi@NiTiO@CNPs fiber were examined for the enrichment of PAHs in water. Under the obtained conditions, the calibration curves were linear over the concentration ranges of 0.05–200 μg·L–1 with correlation coefficients above 0.999. Limits of detection were between 0.012 μg·L–1 and 0.15 μg·L–1. Relative standard deviations (RSDs) of the intra-day and the inter-day analyses with the single fiber varied from 3.03% to 5.34% and from 3.31% to 5.82%, respectively. Moreover, RSDs for the fiber-to-fiber reproducibility with five fibers fabricated in different batches were between 4.89% and 7.10%. Finally, the applicability of the proposed method was validated via determination of target PAHs in real water samples with the relative recoveries of 82.6%–114%. Notably, the superior extraction performance of the fabricated fiber was still maintained even after more than 250 extraction/desorption cycles due to strong adhesion of the CNPs coating to NiTiONPs.