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1.
聚甲基苯基乙烯基硅氧烷固相微萃取探头的特性   总被引:4,自引:0,他引:4  
用溶胶-凝胶及自由基引发交联方法,成功地制备了聚甲基苯基乙烯基聚硅氧烷和羟基硅油复合涂层的固相微萃取探头,与进口商用探头比较,研制的探头对芳香化合物具有高的萃取能力和热稳定性(350℃)以及长的使用寿命。  相似文献   

2.
Solid-phase microextraction (SPME) is a miniaturized and solvent-free sample preparation technique for chromatographic–spectrometric analysis by which the analytes are extracted from a gaseous or liquid sample by absorption in, or adsorption on, a thin polymer coating fixed to the solid surface of a fiber, inside an injection needle or inside a capillary. In this paper, the present state of practical performance and of applications of SPME to the analysis of blood, urine, oral fluid and hair in clinical and forensic toxicology is reviewed. The commercial coatings for fibers or needles have not essentially changed for many years, but there are interesting laboratory developments, such as conductive polypyrrole coatings for electrochemically controlled SPME of anions or cations and coatings with restricted-access properties for direct extraction from whole blood or immunoaffinity SPME. In-tube SPME uses segments of commercial gas chromatography (GC) capillaries for highly efficient extraction by repeated aspiration–ejection cycles of the liquid sample. It can be easily automated in combination with liquid chromatography but, as it is very sensitive to capillary plugging, it requires completely homogeneous liquid samples. In contrast, fiber-based SPME has not yet been performed automatically in combination with high-performance liquid chromatography. The headspace extractions on fibers or needles (solid-phase dynamic extraction) combined with GC methods are the most advantageous versions of SPME because of very pure extracts and the availability of automatic samplers. Surprisingly, substances with quite high boiling points, such as tricyclic antidepressants or phenothiazines, can be measured by headspace SPME from aqueous samples. The applicability and sensitivity of SPME was essentially extended by in-sample or on-fiber derivatization. The different modes of SPME were applied to analysis of solvents and inhalation narcotics, amphetamines, cocaine and metabolites, cannabinoids, methadone and other opioids, fatty acid ethyl esters as alcohol markers, γ-hydroxybutyric acid, benzodiazepines, various other therapeutic drugs, pesticides, chemical warfare agents, cyanide, sulfide and metal ions. In general, SPME is routinely used in optimized methods for specific analytes. However, it was shown that it also has some capacity for a general screening by direct immersion into urine samples and for pesticides and other semivolatile substance in the headspace mode.  相似文献   

3.
建立了以纳米SiO2膜为萃取头涂层的固相微萃取(SPME)-气相色谱(GC)联用测定蔬菜中5种农药残留 (p,p′-DDD, p,p′-DDE, o,p′-DDT, p,p′-DDT, 联苯菊酯)的新方法. 探讨并优化了萃取时间、萃取温度和转子转速等参数.  相似文献   

4.
Nafion/活性炭涂层固相微萃取探头的制备与应用研究   总被引:4,自引:0,他引:4  
采用Nafion和活性炭粉末作为固相涂层在不锈钢丝上交替涂制了固相微萃取探头(SPME),研究了它的特性,并与商品类似探头和单纯的Nafion探头作了比较。该探头可比商品探头(SPME)的富集率高1个数量级。由于Nafion有很强的极性,因此它对极性化合物有很强的萃取能力,适合萃取醇等物质。用该探头测定了醇类、酯类物质,检出限低于10ng/mL,相对标准偏差RSD<6 3%。  相似文献   

5.
Nanostructured titania-based solid-phase microextraction (SPME) fibers were fabricated through the in situ oxidation of titanium wires with H2O2 (30%, w/w) at 80 °C for 24 h. The obtained SPME fibers possess a ∼1.2 μm thick nanostructured coating consisting of ∼100 nm titania walls and 100-200 nm pores. The use of these fibers for headspace SPME coupled with gas chromatography with electron capture detection (GC-ECD) resulted in improved analysis of dichlorodiphenyltrichloroethane (DDT) and its degradation products. The presented method to detect DDT and its degradation products has high sensitivity (0.20-0.98 ng L−1), high precision (relative standard deviation R.S.D. = 9.4-16%, n = 5), a wide linear range (5-5000 ng L−1), and good linearity (coefficient of estimation R2 = 0.991-0.998). As the nanostructured titania was in situ formed on the surface of a titanium wire, the coating was uniformly and strongly adhered on the titanium wire. Because of the inherent chemical stability of the titania coating and the mechanical durability of the titanium wire substrate, this new SPME fiber exhibited long life span (over 150 times).  相似文献   

6.
Low-temperature nonthermal plasma has been used to prepare solid-phase microextraction (SPME) fibers with high adsorbability, long-term serviceability, and high reproducibility. Graphite rods serving as fiber precursors were treated by an air plasma discharged at 15.2-15.5 kV for a duration of 8 min. Sampling results revealed that the adsorptive capacity of the homemade fiber was 2.5-34.6 times that of a polyacrylate (PA) fiber for alcohols (methanol, ethanol, isopropyl alcohol, n-butyl alcohol), and about 1.4-1.6 times and 2.5-5.1 times that of an activated carbon fiber (ACF) for alcohols and BTEX (benzene, toluene, ethylbenzene, and xylenes), respectively. It is confirmed from FTIR (Fourier transform infrared spectrophotometer) and SEM (scanning electron microscope) analyses that the improvement in the adsorptive performance attributed to increased surface energy and roughness of the graphite fiber. Using gas chromatography (GC)-flame-ionization detector (FID), the limits of detection (LODs) of the alcohols and BTEX ranged between 0.19 and 3.75 μg L−1, the linear ranges were between 0.6 and 35619 μg L−1 with good linearity (R2 = 0.9964-0.9997). It was demonstrated that nonthermal plasma offers a fast and simple method for preparing an efficient graphite SPME fiber, and that SPME using the homemade fiber represents a sensitive and selective extraction method for the analysis of a wide range of organic compounds.  相似文献   

7.
A new fiber for solid-phase microextraction (SPME) employing a metallic support coated with an inorganic material is proposed. A nitinol alloy (NiTi) was used as the support material due to its super elasticity and shape memory properties. Zirconium oxide (ZrO2) was electrodeposited onto NiTi using chronoamperometry. The surface characteristics and morphology of the coated and uncoated support were evaluated through scanning electronic microscopy and dispersive energy microanalysis. This assembly was applied in the extraction of three halophenols from aqueous samples. A multivariate approach was used for optimization of the variables involved in the system. The Doehlert matrix was used for evaluation of the best derivatization conditions and a Box-Behnken design to obtain the best extraction conditions. In order to investigate the repeatability, one fiber was used for six extraction tests under similar conditions and the relative standard deviations (R.S.D.) were lower than 12.5%. Detection limits were lower than 0.30 ng mL−1. Correlation coefficients were higher than 0.997. Extraction efficiency of the NiTi-ZrO2 fiber was similar to a PDMS 7 μm commercial fiber, even though it had a lower coating thickness of 1.35 μm. Considering the amount extracted per unit volume, the NiTi-ZrO2 fiber had a better extraction profile when compared to commercial fibers. The new SPME fiber has a lifetime of over 500 extractions. Thus, it is a promising alternative for low-cost analysis, as the proposed fiber is robust, and easily and inexpensively prepared.  相似文献   

8.
A novel amino-functionalized polymer was synthesized using 3-(trimethoxysilyl) propyl amine (TMSPA) as precursor and hydroxy-terminated polydimethylsiloxane (OH-PDMS) by sol–gel technology and coated on fused-silica fiber. The synthesis was designed in a way to impart polar moiety into the coating network. The scanning electron microscopy (SEM) images of this new coating showed the homogeneity and the porous surface structure of the film. The efficiency of new coating was investigated for headspace solid-phase microextraction (SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography–mass spectrometry (GC–MS) analysis. Effect of different parameters influencing the extraction efficiency such as extraction temperature, extraction time, ionic strength and pH was investigated and optimized. In order to improve the separation efficiency of phenolic compounds on chromatography column all the analytes were derivatized prior to extraction using acetic anhydride at alkaline condition. The detection limits of the method under optimized conditions were in the range of 0.02–0.05 ng mL−1. The relative standard deviations (R.S.D.) (n = 6) at a concentration level of 0.5 ng mL−1 were obtained between 6.8 and 10%. The calibration curves of chlorophenols showed linearity in the range of 0.5–200 ng mL−1. The proposed method was successfully applied to the extraction from spiked tap water samples and relative recoveries were higher than 90% for all the analytes.  相似文献   

9.
A method based on immersed solid-phase microextraction (SPME) and gas chromatography mass spectrometry detection (GC-MS) for the determination of organophosphorous pesticides (OPPs) in aqueous samples was developed. A sol-gel based coating fiber was prepared using 3-(trimethoxysilylpropyl) amine as precursor. The synthesized fiber was prepared in a way to impart polar moiety into the coating network and would be more suitable for extracting polar and semi-polar organic pollutants. Important parameters influencing the extraction process were optimized and an extraction time of 40 min at 30 °C gave maximum peak area, when NaCl (20% w/v) was added to the aqueous sample. The linearity for disulfoton, phorate and sulfotep was in the concentration range of 0.01 to 5 ng mL− 1 and for parathion and O,O,O-triethylthiphosphate was in the range of 0.01 to 50 ng mL− 1. Limits of detection ranged from 1 ng L− 1, for parathion, to 0.05 ng L− 1, for disulfoton using time-scheduled selected ion monitoring (SIM) mode, and the RSD% values were all below 10.5% at the 1 ng mL− 1 level. The developed method was successfully applied to real water samples while the relative recovery percentages obtained for the spiked water samples were from 80 to 115%.  相似文献   

10.
Summary Extra-fine powdered activated charcoal has been used as stationary phase (coating layer) in solid-phase microextraction (SPME). The efficiency and reliability of the prepared device have been investigated for the extraction of some volatile organic compounds such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) from the headspace of water samples. Monitoring of the extracted compounds and further quantitative analysis of the real samples have been performed by capillary GC-FID. Effects of several factors such as temperature, addition of salt, and stirring speed on extraction efficiency and exposure time have been studied. Under optimum conditions, extraction recoveries for these compounds from 50 mL water were >95%. The calibration graphs were linear in the range 5 to 104 pg mL−1 and the detection limit for each BTEX compound was 1.5–2 pg mL−1. The results obtained by use of this porous layer activated charcoal (PLAC)-coated fiber have also been compared with results reported in the literature by use of a polydimethylsiloxane (PDMS)-coated fiber. Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996  相似文献   

11.
A novel nano-structured copolymer of aniline and m-amino benzoic acid (m-ABA) was introduced as a coating of solid phase microextraction (SPME) of saturated-fatty acids in zooplanktons by coupling to gas chromatography-mass spectrometry (GC-MS). The nano-structured coating was prepared using co-polymerization of m-aminobenzoic acid and aniline. Improved temperature resistance (up to 350°C), relatively improved life time (more than 50 times) and satisfactory extraction efficiency were obtained by insertion of carboxylate groups into the framework of polyaniline. Different extraction parameters such as extraction temperature, extraction time, ionic strength, stirring rate and headspace volume were investigated and optimized. Single fiber repeatability and fiber-to-fiber reproducibility were <5.7% and <10.2%, respectively and the limits of detection varied from 0.01 (C14:0) to 6.07 μg L(-1) (C20:0). Correlation coefficients (R(2)) of the calibration curves ranged from 0.992 (C20:0) to 0.998 (C18:0) with a linearity from 0.5 to 200 μg mL(-1). The recoveries obtained ranged from 83% (C16:0) to 115% (C14:0).  相似文献   

12.
A dispersive solid-phase microextraction (dispersive-SPME) method for the determination of tetracycline, oxytetracycline, chlortetracycline and doxycycline is proposed. Different silica-based and polymeric sorbents were evaluated for their capacity to simultaneously preconcentrate tetracyclines (TCs) in the dispersive format from aqueous or organic solutions. Silica-based sorbents especially functionalized with primary amine, secondary amine, or carbonyl groups have showed higher capacity than polymeric sorbents under organic environment. In the proposed dispersive solid-phase microextraction method, after extraction with acetonitrile and salt-promoted partitioning, TCs were adsorbed to a small amount of dispersive silica-based primary and secondary amine sorbents, desorbed with a small volume of desorption solution, and determined by high-performance liquid chromatography with diode-array detection. Under the optimal conditions, recoveries were determined for surface water and milk samples spiked at 10 ng/mL and 50–150 ng/g, respectively, and quantification was achieved by matrix-matched calibration. The calibration curves of four TCs in both samples showed linearity with a correlation coefficient value above 0.997. Average recoveries ranged from 97.1 to 104.1% and the precision was from 2.0 to 5.6%. Limits of detection ranged from 0.7 to 3.5 ng/mL and from 7.9 to 35.3 ng/g for four TCs surface in surface water and milk samples, respectively.  相似文献   

13.
An approach to the synthesis of hydroxyl-terminated polymethylphenylsiloxane (PMPS-OH) was proposed and the synthesized PMPS-OH was successfully applied as a precursor to prepare a novel coating for solid-phase microextraction (SPME) via the sol-gel process. The thickness and length of the prepared coating was 70 μm and 1.5 cm, respectively. The extraction efficiency of the PMPS-coated fiber for selected pesticides was higher than that of commercial fibers including 100 μm polydimethylsiloxane (PDMS), 85 μm polyacrylate (PA) and 65 μm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The influence of the extraction process, extraction temperature, extraction time, stirring rate, ionic strength, GC inlet conditions, desorption temperature and time for PMPS-coated fiber application was studied and optimized. Several experiments were carried out to evaluate the analytical characteristics of the proposed SPME-GC-ECD method under optimized conditions. The linearity was from 0.5 to 100 ng g−1 for p,p′-DDE, p,p′-DDD and bifenthrin, and from 2 to 100 ng g−1 for o,p′-DDT, p,p′-DDT, fenpropathrin, beta-cyfluthrin and cyhalothrin. The detection limits of these pesticides were between 0.13 and 1.45 ng g−1. The recovery of the pesticides spiked in various vegetables at 4 ng g−1 ranged from 42.9% to 105.3%, and the relative standard deviations were less than 16.2%.  相似文献   

14.
Cathodic electrodeposition (CED) has received great attention in metal-organic frameworks (MOFs) synthesis due to its distinguished properties including simplicity, controllability, mild synthesis conditions, and product continuously. Here, we report the fabrication of thin (Et3NH)2Zn3(BDC)4 (E-MOF-5) film coated solid phase microextraction (SPME) fiber by a one-step in situ cathodic electrodeposition strategy. Several etched stainless steel fibers were placed in parallel in order to achieve simultaneously electrochemical polymerization. The influence of different polymerization parameters Et3NHCl concentration and polymerization time were evaluated. The proposed method requires only 20 min for the preparation of E-MOF-5 coating. The optimum coating showed excellent thermal stability and mechanical durability with a long lifetime of more than 120 repetitions SPME operations, and also exhibited higher extraction selectivity and capacity to four estrogens than commonly-used commercial PDMS coating. The limits of detection for the estrogens were 0.17–0.56 ng mL−1. Fiber-to-fiber reproducibility (n = 8) was in the respective ranges of 3.5%–6.1% relative standard deviation (RSD) for four estrogens for triplicate measurements at 200 ng mL−1. Finally, the (E-MOF-5) coated fiber was evaluated for ethinylestradiol (EE2), bisphenol A (BPA), diethylstilbestrol (DES), and hexestrol (HEX) extraction in the spiked milk samples. The extraction performance of this new coating was satisfied enough for repeatable use without obvious decline.  相似文献   

15.
Yuling Hu 《Talanta》2010,80(5):2099-46
The combination of molecular imprinting and solid-phase microextraction (SPME) technique provides a powerful sample preparation tool in terms of selectivity, simplicity, and flexibility. This paper reports a novel molecularly imprinted polymer (MIP) coated SPME fiber with 17β-estradiol as template by improved multiple co-polymerization method. The obtained fiber exhibits excellent characteristics such as high porosity, good thermal and chemical stability. Extraction performance shows that the MIP-coated fiber has stronger affinity to the template molecule as compared with the commercial SPME fibers and the control polymer-coated fiber without addition of template. Owing to the shape and structural compatibility, the obtained fiber also demonstrated specific selectivity to the structural related compounds of 17β-estradiol, such as estriol, estrone and 17α-ethynylestradiol, and thus can be applied to simultaneous determination of these estrogens from complex samples coupled with high performance liquid chromatography. The variables that influence extraction were investigated. The MIP-coated fiber demonstrated its efficiency for extraction of estrogens in fishery samples. The detection limits were in the range of 0.98-2.39 μg L−1, and the recoveries were 80.0-83.6% and 85.0-94.1% for fish and shrimp tissue samples, respectively.  相似文献   

16.
A new ionic liquid (IL) based solid-phase microextraction (SPME) fiber was investigated and used for headspace (HS) extraction of methyl tert-butyl ether (MTBE) in a gasoline sample. Using the new IL coated HS-SPME fiber with the combination of gas chromatography-flame ionization detection (GC-FID); sub-to-low μg L−1 concentrations of MTBE were detected. Four different ILs including 1-butyl-3-methylimidazolium tetraflouroborate ([C4C1IM] [BF4]), 1-octyl-3-methylimidazolium tetraflouroborate ([C8C1IM] [BF4]), 1-octyl-3-methylimidazolium hexaflourophosphate ([C8C1IM] [PF6]) and 1-ethyl-3-methylimidazolium ethylsulphate ([C2C1IM] [ETSO4]) were synthesized and examined for extraction, preconcentration and determination of MTBE. It was observed that [C8C1IM] [BF4] showed the highest extraction efficiency and possessed the best extractability for MTBE. The fiber coating takes up the compounds from the sample by absorption in the case of liquid coatings. The calibration graph was linear in a concentration range of 1-120 μg L−1 (R2 > 0.994) with the detection limit of 0.09 μg L−1 level. The new IL-coated fiber was applied successfully for the determination of MTBE in a gasoline sample with good recoveries between 90 and 95%.  相似文献   

17.
This study describes a new optimization strategy for internally cooled solid-phase microextraction based on a multivariate approach. The coating temperature was changed in an extraction while manipulating the extraction times to improve the extraction of compounds with different volatilities. Polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PEs) and adipate were used as model compounds in this study. The optimization strategy was in two steps: (1) multivariate optimization of extraction time and initial coating temperature and (2) multivariate optimization of total extraction time and the time required to cool the coating to a lower temperature as determined in step 1. The observed analytical response in relation to the coating temperature was found to be dependent on the analyte volatility and size. The optimized extraction condition for PEs was 23 min extraction while maintaining the coating at 140°C, followed by 7 min of cooling the coating at 10°C. For the PAHs the coating temperature was maintained at 60°C for the first 20 min and at 5°C in the last 20 min of extraction. Comparisons have been made between the proposed optimized conditions with the conventional internally cooled fiber approach and the results thoroughly discussed. The proposed optimization strategy was found to be more effective for all the analytes, especially for the semi-volatiles, compared to the conventional method.  相似文献   

18.
A new method is presented for the determination of DMA in water as its 9-fluorenylmethyl chloroformate (FMOC) derivative using solid-phase microextraction (SPME) and liquid chromatography. The method is based on the employment of SPME fibres coated with carbowax-templated resin (CW-TR) for analyte extraction and derivatization. The fibres were successively immersed in the samples, in a solution of o-phthalaldialdehyde and N-acethyl-l-cysteine (OPA–NAC) and finally, in a solution of FMOC. OPA–NAC reacted on the fibre with possible primary aliphatic amines present in the samples, particularly with PA which is a direct interferent in the determination of DMA with FMOC. In such a way, the formation of PA–FMOC during the second stage was prevented, and thus the method was selective for DMA. The proposed procedure was applied to the determination of DMA in the 1.0–10.0 μg/mL range. The method provided suitable linearity, accuracy and reproducibility, and limits of detection and quantification of 0.3 and 1.0 μg/mL, respectively. The applicability of the method for the determination of DMA in different types of water is shown.  相似文献   

19.
Two kinds of mesoporous cellular foams (MCFs), including mesoporous silica materials (MCF-1) and phenyl modified mesoporous materials (Ph-MCF-1), were synthesized and for the first time used as fiber-coating materials for solid-phase microextraction (SPME). By using stainless steel wire as the supporting core, four types of fibers were prepared by sol–gel method and immobilized by epoxy-resin method. To evaluate the performance of the home-made fibers for SPME, seven brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS) and related compounds were selected as analytes. The main parameters that affect the extraction and desorption efficiencies, such as extraction temperature, extraction time, desorption time, stirring rate and ionic strength of samples were investigated and optimized. The optimized SPME coupled with high performance liquid chromatography (HPLC) was successfully applied to the determination of the seven BFRs in water samples. The linearity range was from 5.0 to 1000 μg L−1 for each compound except TBBPS (from 1.0 to 1000 μg L−1), with the correlation coefficients (r2) ranging from 0.9993 to 0.9999. The limits of detection of the method were 0.4–0.9 μg L−1. The relative standard deviations varied from 1.2 to 5.1% (n = 5). The repeatability of fiber-to-fiber and batch-to-batch was 2.5–6.5% and 3.2–6.7%. The recoveries of the BFRs from aqueous samples were in the range between 86.5 and 103.6%. Compared with three commercial fibers (100 μm PDMS, 85 μm PA and 65 μm PDMS/DVB), the MCFs-coated fiber showed about 3.5-fold higher extraction efficiency.  相似文献   

20.
A new line of solid-phase microextraction (SPME) coatings suitable for use with liquid chromatography applications was recently developed to address the limitations of the currently available coatings. The proposed coatings were immobilized on the metal fiber core and consisted of a mixture of proprietary biocompatible binder and various types of coated silica (octadecyl, polar embedded and cyano) particles. The aim of this research was to perform in vitro assessment of these new SPME fibers in order to evaluate their suitability for drug analysis and in vivo SPME applications. The main parameters examined were extraction efficiency, solvent resistance, preconditioning, dependence of extraction kinetics on coating thickness, carryover, linear range and inter-fiber reproducibility. The performance of the proposed coatings was compared against commercial Carbowax-TPR (CW-TPR) coating, when applicable. The fibers were evaluated for the extraction of drugs of different classes (carbamazepine, propranolol, pseudoephedrine, ranitidine and diazepam) from plasma and urine. The analyses were performed using liquid chromatography-tandem mass spectrometry. The results show that the fibers perform very well for the extraction of biological fluids with no sample pre-treatment required and can also be used for in vivo sampling applications of flowing blood. A coating thickness of 45 μm was found to be a good compromise between extraction capacity and extraction kinetics. Due to the high extraction efficiency of these coatings, pre-equilibrium SPME with very short extraction times (2 min) can be employed to increase sample throughput. Inter-fiber reproducibility was ≤11% R.S.D. (n = 10) for model drugs examined in plasma, which is a significant improvement over polypyrrole coatings reported in literature, and permits single fiber use for in vivo applications.  相似文献   

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