离子液体和聚离子液体固相微萃取涂层制备及应用进展

固相微萃取(Solid-phase microextraction,SPME)技术因其具有操作简单、萃取时间短、无需有机溶剂、易于自动化操作等优点,成为近年来发展起来的一种新型样品前处理技术。涂层是SPME技术的核心,决定了涂层萃取的选择性和容量。离子液体和聚离子液体因具有环境友好、蒸汽压低、热稳定性好、设计灵活、粘度大等特点,已作为一类新的涂层材料广泛应用于SPME,并对各种分析物均展现出良好的萃取效果和选择性。本文从制备技术、形貌、选择性、稳定性、寿命、应用等方面综述了近年来离子液体和聚离子液体基SPME涂层的研究进展,对它们的优缺点进行了对比讨论,并对其未来发展方向进行了展望。     

Are metal-organic frameworks able to provide a new generation of solid-phase microextraction coatings? – A review

Solid-phase microextraction (SPME) is a powerful technique commonly used in sample preparation for extraction/preconcentration of analytes from a wide variety of samples. Among the trends in improving SPME applications, current investigations are focused on the development of novel coatings able to improve the extraction efficiency, sensitivity, and thermal and mechanical stability, within other properties, of current commercial SPME fibers. Metal-organic frameworks (MOFs) merit to be highlighted as promising sorbent materials in SPME schemes. MOFs are porous hybrid materials composed by metal ions and organic linkers, presenting the highest surface areas known, with ease synthesis and high tuneability, together with adequate chemical and thermal stability. For MOF based-SPME fibers, it results important to pretreat adequately the SPME supports to ensure the correct formation of the MOF onto the fiber or the attachment MOF-support. This, in turn, will increase the final stability of the fiber while generating uniform coatings. This review provides a critical overview of the current state of the use of MOFs as SPME coatings, not only highlighting the advantages of these materials versus commercial SPME coatings in terms of stability, selectivity, and sensitivity; but also insightfully describing the current methods to obtain reproducible MOF-based SPME coatings.     

Magnetron sputtering Si interlayer: a protocol to prepare solid phase microextraction coatings on metal-based fiber

Use of metal fibers in solid phase microextraction (SPME) can overcome the fragility drawback of conventional fused-silica ones. However, the surface modification of metal substrates is rather difficult, which largely prevents many mature traditional techniques, such as sol-gel and chemical bonding, being used in fabrication of SPME coating on metal-based fibers. This study demonstrates a protocol to resolve this problem by magnetron sputtering a firm Si interlayer on stainless steel fiber. The Si interlayer was easily modified active group, and attached with a multiwalled carbon nanotubes (MWCNTs) coating using the reported approach. The as-prepared MWCNTs/Si/stainless steel wire fiber not only preserved the excellent SPME behaviors of MWCNTs coatings, but also exhibited a number of advantages including high rigidity, long service life, and good stability at high temperature, in acid and alkali solutions. This new surface modification technique might provide a versatile approach to prepare sorbent coatings on unconfined substrates using traditional methods.     

Electrochemically prepared solid-phase microextraction coatings—A review

During the last decade, electrochemically prepared coatings have gained widespread acceptance for solid-phase microextraction (SPME) applications. The current review classified these coatings as electropolymerized conductive polymers (CPs), electrodeposited metal oxides, electrophoretically deposited carbon nanotubes (CNTs) and anodized metals. These electrochemical methods resulted in easily controlled and reproducible SPME coatings with inherent characteristics such as biocompatibility, thermal stability and porous structure. The objective of this review is to provide a concise overview of recent developments in the electrochemically prepared SPME coatings and their analytical applications.     

Ionic liquids in solid-phase microextraction: a review

Solid-phase microextraction (SPME) has undergone a surge in popularity within the field of analytical chemistry in the past two decades since its introduction. Owing to its nature of extraction, SPME has become widely known as a quick and cost-effective sample preparation technique. Although SPME has demonstrated extraordinary versatility in sampling capabilities, the technique continues to experience a tremendous growth in innovation. Presently, increasing efforts have been directed towards the engineering of novel sorbent material in order to expand the applicability of SPME for a wider range of analytes and matrices. This review highlights the application of ionic liquids (ILs) and polymeric ionic liquids (PILs) as innovative sorbent materials for SPME. Characterized by their unique physico-chemical properties, these compounds can be structurally-designed to selectively extract target analytes based on unique molecular interactions. To examine the advantages of IL and PIL-based sorbent coatings in SPME, the field is reviewed by gathering available experimental data and exploring the sensitivity, linear calibration range, as well as detection limits for a variety of target analytes in the methods that have been developed.     

Application of solid-phase microextraction in analytical toxicology

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.     

新型的样品前处理技术-固相微萃取

文中对固相微萃取,作为一种试样预处理的新技术,在1990-2004年的进展作了评述,介绍了固相微萃取技术的装置、试验方法、原理、涂层、影响因素、应用及发展趋势,引用文献39篇。     

固相微萃取的涂层进展

 对固相微萃取 (SPME)的固定相涂层的发展进行了综述。阐述了商品化和非商品化涂层的各自特点 ,并对涂层的选择性和SPME技术作了简单的介绍。     

Current trends in solid-phase microextraction (SPME) fibre coatings

This critical review presents information on known and innovative approaches to the manufacture of fibre coatings used in solid-phase microextraction (SPME). The properties, advantages and drawbacks of the different types of commercially available SPME fibre coatings are discussed in detail, as are those of novel types of coatings and the methodologies of their preparation. The applications of fibre coatings in the solid-phase microextraction of a broad spectrum of analytes are analysed, with particular emphasis on the sampling of polar analytes from polar matrices (174 references).     

Recent developments in solid-phase microextraction coatings and related techniques

During the last decade, solid-phase microextraction (SPME) has gained widespread acceptance for analyte matrix separation and preconcentration. Relatively few data are currently available dealing with in-house production of fibres with tailor-made properties to be used for SPME, though recently the number of publications evaluating new coatings has been considerably growing. This review, centred on publications that appeared during the last five years, is resuming different approaches which can be used for fibre production and further summarises alternative techniques closely related to SPME, such as in-tube extraction or single-drop microextraction (SDME). The aim is to give the reader a concise overview of recent developments in new coating procedures and materials, including the respective applications.     

固相微萃取中高分子涂层的研究

聚甲基乙烯基硅氧烷首次被用作固相微萃取（ＳＰＭＥ）装置的固相涂层,通过顶空固相微萃取气相色谱分析（ＨＳ－ＳＰＭＥ－ＧＣ）对使用聚甲基乙烯基硅氧烷固相涂层的ＳＰＭＥ装置进行了评价。对其使用厚度、温度及选择性进行了较深入的研究,找到了它的最佳使用条件和适用范围,并与商品化的ＳＰＭＥ涂层作了比较。对ＨＳ－ＳＰＭＥ－ＧＣ和ＨＳ－ＧＣ两种方法也作了比较,指出两者的适用范围不同。     

Sol-gel-coated oligomers as novel stationary phases for solid-phase microextraction

Amphiphilic and hydrophilic oligomers were synthesized and coated on fused silica capillaries using a sol-gel technique. Sol-gel-coated capillaries were evaluated for the solid-phase microextraction and preconcentration of a wide variety of non-polar and polar analytes. Both types of coatings were stable under high temperature (up to 280 degrees C). The extraction efficiency of the sol-gel coatings was evaluated for the extraction of both non-polar and polar analytes, including organochlorine pesticides, triazine herbicides, estrogens and alkylphenols (APs) and bisphenol-A (BPA). Compared with commercially available solid-phase microextraction (SPME) adsorbents such as poly(dimethylsiloxane)divenylbenzene and polyacrylate, the new materials showed comparable selectivity and sensitivity towards both non-polar and polar analytes. The new coatings gave good linearity and detection limits. For example with triazines, a detection limit of <0.005 microl l(-1), precision from 5.0 to 11.0% (n = 6) and linearity of the calibration plots (0.5 to 50 microl l(-1)) were obtained. The sol-gel coated SPME capillaries were used for the determination of triazine herbicides in reservoir water samples collected in Singapore.     

Applications of solid-phase microextraction in food analysis

Food analysis is important for the evaluation of the nutritional value and quality of fresh and processed products, and for monitoring food additives and other toxic contaminants. Sample preparation, such as extraction, concentration and isolation of analytes, greatly influences the reliable and accurate analysis of food. Solid-phase microextraction (SPME) is a new sample preparation technique using a fused-silica fiber that is coated on the outside with an appropriate stationary phase. Analyte in the sample is directly extracted to the fiber coating. The SPME technique can be used routinely in combination with gas chromatography (GC), GC–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC) or LC–MS. Furthermore, another SPME technique known as in-tube SPME has also been developed for combination with LC or LC–MS using an open tubular fused-silica capillary column as an SPME device instead of SPME fiber. These methods using SPME techniques save preparation time, solvent purchase and disposal costs, and can improve the detection limits. This review summarizes the SPME techniques for coupling with various analytical instruments and the applications of these techniques to food analysis.     

Application of on-site solid-phase microextraction in aquatic dissipation studies of profoxydim in rice

The application of a manual operated solid-phase microextraction (SPME)-HPLC interface is discussed for the analysis of thermally labile analytes in aqueous matrices. The technique has been applied on-site at a flooded rice field to demonstrate its potential for real time extraction of the herbicide profoxydim. Thus, compounds which would otherwise easily degrade in the aqueous matrices within hours or days could be determined more accurately. The fibers were shipped back to the laboratory with express delivery where the target analyte was desorbed from the fiber and determined by HPLC-UV analysis. The SPME method was characterized by significant ruggedness where conventional techniques such as liquid-liquid extraction and solid-phase extraction require additional shipping and handling costs and time-consuming multiple sample preparation steps. In general, any delay in shipping the aqueous samples to the laboratory has the potential for sample degradation and a loss in accuracy when using non on-site extraction techniques. Fifty microm Carbowax-templated resin coatings were most suitable for coupling SPME to HPLC in order to achieve a high sensitivity for polar analytes. The SPME technique was characterized by a good sensitivity and a precision less than 10% RSD. The SPME-LC-UV method was linear over at least three orders of magnitude while achieving a limit of detection in the lower microg/l range. The on-site SPME method has shown significantly increased accuracy. Profoxydim was determined at concentrations of ca. 180 microg/l 3 h after an application on a flooded bare soil field.     

Automated in-tube solid-phase microextraction-high-performance liquid chromatography for carbamate pesticide analysis

In-tube solid-phase microextraction (SPME) is an automated version of SPME that can be easily coupled to a conventional HPLC autosampler for on-line sample preparation, separation and quantitation. It has been termed "in-tube" SPME because the extraction phase is coated inside a section of fused-silica tubing rather than coated on the surface of a fused-silica rod as in the conventional syringe-like SPME device. The new in-tube SPME technique has been demonstrated as a very efficient extraction method for the analysis of polar and thermally labile analytes. The in-tube SPME-HPLC method used with the FAMOS autosampler from LC Packings was developed for detecting polar carbamate pesticides in clean water samples. The main parameters relating to the extraction and desorption processes of in-tube SPME (selection of coatings, aspirate/dispense steps, selection of the desorption solvents, and the efficiency of desorption solvent, etc.) were investigated. The method was evaluated according to the reproducibility, linear range and limit of detection. This method is simple, effective, reproducible and sensitive. The relative standard deviation for all the carbamates investigated was between 1.7 and 5.3%. The method showed good linearity between 5 and 10000 microg/l with correlation coefficients between 0.9824 and 0.9995. For the carbamates studied, the limits of detection observed are lower than or similar to that of US Environmental Protection Agency or National Pesticide Survey methods. Detection of carbaryl present in clean water samples at 1 microg/l is possible.     

Surface energy characteristics of toner particles by automated inverse gas chromatography

This study develops a method for the analysis of biocides Irgarol 1051 and Sea Nine 211 in environmental water samples, using solid-phase microextraction (SPME). Their determination was carried out using gas chromatography with flame thermionic (FTD), electron-capture (ECD) and mass spectrometric detection. The main parameters affecting the SPME process such as adsorption-time profile, salt additives and memory effect were studied for five polymeric coatings commercially available for solid-phase microextraction: poly(dimethylsiloxane) (100 and 30 microm), polyacrylate, poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB 65 microm) and Carbowax-divinylbenzene (65 microm). The method was developed using spiked natural waters such as tap, river, sea and lake water in a concentration range of 0.5-50 microg/l. All the tested fiber coatings have been evaluated with regard to sensitivity, linear range, precision and limits of detection. Typical RSD values (triplicate analysis) in the range of 3-10% were obtained depending on the fiber coating and the compound investigated. The recoveries of biocides were in relatively high levels 60-118% and the calibration curves were reproducible and linear (R2>0.990) for both analytes. The SPME partition coefficients (Kf) of both compounds were also calculated experimentally in the proposed conditions for all fibers using direct sampling. Finally the influence of organic matter such as humic acids on extraction efficiency was studied, affecting mostly Sea Nine 211 uptake by the fiber. Optimum analytical SPME performance was achieved using the PDMS-DVB 65 microm fiber coating in ECD and FTD systems for Sea Nine 211 and Irgarol 1051, respectively.     

Analysis of organic compounds in environmental samples by headspace solid phase microextraction

The analysis of samples contaminated by organic compounds is an important aspect of environmental monitoring. Because of the complex nature of these samples, isolating target organic compounds from their matrices is a major challenge. A new isolation technique, solid phase microextraction, or SPME, has recently been developed in our laboratory. This technique combines the extraction and concentration processes into one step; a fused silica fiber coated with a polymer is used to extract analytes and transfer them into a GC injector for thermal desorption and analysis. It is simple, rapid, inexpensive, completely solvent-free, and easily automated. To minimize matrix interferences in environmental samples, SPME can be used to extract analytes from the headspace above the sample. The combination of headspace sampling with SPME separates volatile and semi-volatile analytes from non-volatile compounds, thus greatly reducing the interferences from non-target compounds. This paper reports the use of headspace SPME to isolate volatile organic compounds from various matrices such as water, sand, clay, and sludge. By use of the technique, benzene, toluene, ethyl-benzene, and xylene isomers (commonly known as BTEX), and volatile chlorinated compounds can be efficiently isolated from various matrices with good precision and low limits of detection. This study has found that the sensitivity of the method can be greatly improved by the addition of salt to water samples, water to soil samples, or by heating. Headspace SPME can also be used to sample semi-volatile compounds, such as PAHs, from complex matrices.     

Automated sample preparation using in-tube solid-phase microextraction and its application -- a review

Sample preparation, such as extraction, concentration, and isolation of analytes, greatly influences their reliable and accurate analysis. In-tube solid-phase microextraction (SPME) is a new effective sample preparation technique using an open tubular fused-silica capillary column as an extraction device. Organic compounds in aqueous samples are directly extracted and concentrated into the stationary phase of capillary columns by repeated draw/eject cycles of sample solution, and they can be directly transferred to the liquid chromatographic column. In-tube SPME is an ideal sample preparation technique because it is fast to operate, easy to automate, solvent-free, and inexpensive. On-line in-tube SPME-performed continuous extraction, concentration, desorption, and injection using an autosampler, is usually used in combination with high performance liquid chromatography and liquid chromatography-mass spectrometry. This technique has successfully been applied to the determination of various compounds such as pesticides, drugs, environmental pollutants, and food contaminants. In this review, an overview of the development of in-tube SPME technique and its applications to environmental, clinical, forensic, and food analyses are described.     

Gas chromatographic determination of 2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid sunscreen agents in swimming pool and bathing waters by solid-phase microextraction

A method has been developed for the trace determination of two sunscreen constituents (2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid) in water samples, which are commonly used in commercial formulations. The method employs solid-phase microextraction (SPME) and gas chromatography with flame ionization and mass spectrometric detection. The technique was developed with headspace and direct sampling in order to demonstrate the applicability of these SPME extraction modes for the identification of these two UV absorbing compounds in waters. The main parameters affecting the SPME process, such as desorption time, extraction time profile, salt additives, pH, and temperature, were investigated. The poly(dimethylsiloxane) 100-microm and polyacrylate 85-microm fiber coatings were found to be the most efficient for the extraction of these compounds from aqueous matrices. Linear calibration curves in the wide range of 10-500 microg/l were obtained for both compounds yielding typical RSD values of 5-9% for both extraction modes. The recoveries were relatively high, 82-98%, with quantitation limits below 1 microg/l. A comparison between the proposed methods and the conventional multiresidue solid-phase extraction revealed that the proposed technique(s) can be reliably used for sunscreen residue measurement in water samples with satisfactory results.     

Hydroxyfullerene as a novel coating for solid-phase microextraction fiber with sol-gel technology

Hydroxyfullerene (fullerol) as a novel coating for solid-phase microextraction (SPME) fiber was first prepared by a sol-gel technology. The coating procedure involving sol solution composition and conditioning process was presented. A fullerene polysiloxane surface-bonded porous coating on the fused-silica fiber surface was obtained and confirmed by IR spectra and scanning electron microscopy. The coating has stable performance at high temperature (even to 360 degrees C) and solvents (organic and inorganic) because of the properties of fullerene and the chemical binding between the coating and the fiber surface. The extraction properties of the new coatings to less volatile organic compounds, such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons and polar aromatic amines were investigated using headspace SPME coupled with GC-electron-capture detection and GC-flame ionization detection. In addition, compared with commercial SPME stationary phases, the new coatings showed higher sensitivity, faster velocities of mass transfer for aromatic compound, and possessed planarity molecular recognition for PCBs. Moreover, this fiber was firm, inexpensive, durable and can be prepared simply. The fiber-to-fiber reproducibility was very good.