微萃取技术在环境分析中的应用

微萃取技术是近年来出现的绿色样品前处理技术。它具有操作简便、环境友好等优点,并且在环境、医药及食品等领域得到广泛的应用。本文仅就固相微萃取和液相微萃取在环境分析中的应用作一简要综述。     

Strategies for the microextraction of polar organic contaminants in water samples

In this paper the most recent developments in the microextraction of polar analytes from aqueous environmental samples are critically reviewed. The particularities of different microextraction approaches, mainly solid-phase microextraction (SPME), stir-bar-sorptive extraction (SBSE), and liquid-phase microextraction (LPME), and their suitability for use in combination with chromatographic or electrically driven separation techniques for determination of polar species are discussed. The compatibility of microextraction techniques, especially SPME, with different derivatisation strategies enabling GC determination of polar analytes and improving their extractability is revised. In addition to the use of derivatisation reactions, the possibility of enhancing the yield of solid-phase microextraction methods for polar analytes by using new coatings and/or larger amounts of sorbent is also considered. Finally, attention is also focussed on describing the versatility of LPME in its different possible formats and its ability to improve selectivity in the extraction of polar analytes with acid-base properties by using separation membranes and buffer solutions, instead of organic solvents, as the acceptor solution.     

三嗪基多孔有机材料的合成及在固相微萃取应用中的研究进展

三嗪基多孔有机材料(TPOPs)具有较大的比表面积、可调的孔道结构、较高的热和化学稳定性、丰富的π键体系等诸多优点,目前被广泛应用于气体储存、催化、能源转化和吸附等诸多领域。基于TPOPs的固相微萃取(SPME)技术近年来引起了人们的极大兴趣,成为样品前处理技术领域的研究热点之一。该文简要地综述了近年来TPOPs的合成方法及其在固相微萃取领域的应用与发展,并对该领域研究进行了展望。     

Recent developments in solid-phase microextraction for on-site sampling and sample preparation

On-site sampling and sample preparation favor portable, solventless or even solvent-free techniques. Solid-phase microextraction (SPME) has these advantages. This review focuses on developments between 2007 and early 2011 in microextraction techniques for on-site sampling and sample preparation, including fiber SPME, stir-bar sorptive extraction (SBSE), thin-film microextraction (TFME) and different types of in-needle SPME. The major trends in on-site applications of SPME appear to be fiber and thin-film SPME, microextraction by packed sorbent (MEPS) and the sorbent-packed needle-trap device (NTD). We discuss and compare several aspects of these types of SPME in on-site applications. We also describe sorbent phases for SPME that benefit on-site applications. Finally, we provide a perspective on SPME-based techniques for on-site applications.     

Sorbent- and liquid-phase microextraction techniques and membrane-assisted extraction in combination with gas chromatographic analysis: A review

Approaches are described for on-line and off-line sample pretreatment of liquid samples utilising liquid- and adsorbent- and sorbent-phase microextraction methodologies with GC analysis. Solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), on-line solid-phase extraction (SPE), liquid-phase microextraction (LPME) and membrane-assisted methods are critically evaluated and the applicability of each technique is demonstrated with examples.     

Microporous silica with nanolayer structure coated with renewable organic solvent film as a novel extracting phase: A combination of solid- and liquid-phase microextraction

A new method based on combination of solid- and liquid-phase microextraction was developed. For the first time, porous flower-like silica microstructures with nanometric layers were created on the surface of the stainless steel wire by a new facile hydrothermal process. The fiber, coated with a suitable organic solvent, was applied for microextraction of some organophosphorus pesticides from aqueous samples followed by gas chromatography-nitrogen phosphorous detection. Method detection limits were between 0.6 and 3 ng L⁻¹. Relative standard deviations for intra- and inter-day precision were 4.4–7.3% and 5.1–7.8%, respectively. Fiber-to-fiber reproducibility for five prepared fibers was 6.3–8.4%. Tap, river and waste water samples were analyzed for evaluation of the method in real sample analysis. Relative recoveries for spiked tap, river and waste water samples were in the range of 94–101%, 89–97% and 82–103%, respectively. In addition, the method was compared with two commercial solid-phase microextraction (SPME) fibers, single drop microextraction (SDME) and liquid-phase microextraction (LPME). The present method showed higher extraction efficiency as compared with SDME, LPME and commercial SPME fibers.     

Molecularly imprinted polymers for sample preparation: A review

In spite of the huge development of analytical instrumentation during last two decades, sample preparation is still nowadays considered the bottleneck of the whole analytical process. In this regard, efforts have been conducted towards the improvement of the selectivity during extraction and/or subsequent clean-up of sample extracts. Molecularly imprinted polymers (MIPs) are stable polymers with molecular recognition abilities, provided by the presence of a template during their synthesis and thus are excellent materials to provide selectivity to sample preparation. In the present review, the use of MIPs in solid-phase extraction and solid-phase microextraction as well as its recent incorporation to other extraction techniques such as matrix-solid phase dispersion and stir bar sorptive extraction, among others, is described. The advantages and drawbacks of each methodology as well as the future expected trends are discussed.     

分子印迹聚合物在抗生素残留测定中的应用

抗生素的滥用及残留对生物体和环境造成极大危害,其含量低、种类多、基质复杂,通常需要进行样品前处理结合色谱分析以实现灵敏测定。分子印迹聚合物（MIPs）能选择性识别、有效富集目标分析物并消除干扰,已广泛用于抗生素的样品前处理中。该文对MIPs制备中面临的挑战进行了总结;对2016年以来抗生素MIPs的固相萃取应用进行了综述和展望,主要包括固相萃取、分散固相萃取、磁固相萃取、基质固相分散萃取、固相微萃取、搅拌棒吸附萃取。此外,该文重点介绍了抗生素MIPs的印迹新策略,如多模板、多功能单体、虚拟模板、刺激响应、亲水性印迹等。最后,该文对抗生素MIPs的制备和前处理应用进行了展望。     

Basic principles,recent trends and future directions of microextraction techniques for the analysis of aqueous environmental samples

Microextraction-based sample preparation techniques have exhibited remarkable importance in analytical chemistry since they were first developed in the 1980s. The application of these techniques involves efficient and, at the same time, environmentally-friendly analytical methodologies. They are also generally faster when compared with classical sample preparation techniques, requiring low solvent and sample volumes, and also allowing for automated or semi-automated procedures. This paper provides an overview of the basic principles of sample preparation techniques and the important applications and developments that have taken place in this area over the past five years. These procedures include solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), bar adsorptive microextraction (BAμE), rotating disk sorptive extraction (RDSE), micro solid-phase extraction (μ-SPE) and liquid-phase microextraction (LPME). The main variations are discussed with a focus on recent applications in the analysis of environmental water samples. Lastly, some of the trends and perspectives associated with these outstanding microextraction sample preparation approaches are highlighted.     

Determination of steroid hormones in biological and environmental samples using green microextraction techniques: an overview

Residues of steroid hormones have become a cause for concern because they can affect the biological activity of non-target organisms. Steroid hormones are a potential risk for wildlife and humans through the consumption of contaminated food or water. Their determination requires extraction and clean-up steps, prior to detection, to reach low concentration levels. In recent years, a great effort has been made to develop new analytical methodologies, such as microextraction techniques, that reduce environmental pollution. Researchers have modified old methods to incorporate procedures that use less-hazardous chemicals or that use smaller amounts of them. They are able to do direct analysis using miniaturised equipment and reduced amounts of solvents and wastes. These accomplishments are the main objectives of green analytical chemistry. In this overview, we focus on microextraction techniques for the determination of steroid hormones in biological (e.g., human urine, human serum, fish, shrimp and prawn tissue and milk) and environmental (e.g., wastewaters, surface waters, tap waters, river waters, sewage sludges, marine sediments and river sediments) samples. We comment on the most recent applications in sorptive-microextraction modes, such as solid phase microextraction (SPME) with molecularly imprinted polymers (MIPs), in-tube solid-phase microextraction (IT-SPME), stir-bar sorptive extraction (SBSE) and microextraction in packed sorbent (MEPS). We also describe liquid-phase microextraction (LPME) approaches reported in the literature that are applied to the determination of steroid hormones.     

QSRR Study of GC Retention Indices of Volatile Compounds Emitted from Mosla chinensis Maxim by Multiple Linear Regression

The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid‐phase microextraction (HS‐SPME) and headspace liquid‐phase microextraction (HS‐LPME) combined with gas chromatography‐mass spectrometry (GC‐MS). The main volatiles from Mosla chinensis Maxim were studied in this paper. It can be seen that 61 compounds were separated and identified. Forty‐nine volatile compounds were identified by SPME method, mainly including myrcene, α‐terpinene, p‐cymene, (E)‐ocimene, thymol, thymol acetate and (E)‐β‐farnesene. Forty‐five major volatile compounds were identified by LPME method, including α‐thujene, α‐pinene, camphene, butanoic acid, 2‐methylpropyl ester, myrcene, butanoic acid, butyl ester, α‐terpinene, p‐cymene, (E)‐ocimene, butane, 1,1‐dibutoxy‐, thymol, thymol acetate and (E)‐β‐farnesene. After analyzing the volatile compounds, multiple linear regression (MLR) method was used for building the regression model. Then the quantitative structure‐retention relationship (QSRR) model was validated by predictive‐ability test. The prediction results were in good agreement with the experimental values. The results demonstrated that headspace SPME‐GC‐MS and LPME‐GC‐MS are the simple, rapid and easy sample enrichment technique suitable for analysis of volatile compounds. This investigation provided an effective method for predicting the retention indices of new compounds even in the absence of the standard candidates.     

Recent Progress,Challenges and Prospects in Monitoring Plastic-Derived Xenoestrogens Using Molecularly Imprinted Sorbents

Indoor and outdoor exposure to plastic-derived xenoestrogens, such as phthalates and phenolic compounds, can adversely affect endocrine and reproductive systems in humans and wildlife. To accomplish the extraction of plastic-derived xenoestrogens from environmental samples, molecularly imprinted polymers (MIPs) have been proved to be selective, efficient, and reliable sorbents. Despite some problems associated with the use of MIPs as sorbents, these have been found to be of considerable interest due to their advantages of selectivity, easy synthetic procedures, and better stability over commercially available solid sorbents. Modifications in their synthetic strategies are continuously in progress and new approaches are being made through graphene oxide substrates, nanostructured platforms, nanoferrites, cryogels, and co-electropolymerization to design better sorbents. Apart from this, efforts to create molecularly imprinted solid phase microextraction (SPME) fibers have also been successful in improving the efficiency of the methodology. In future, the use of MIPs developed from advanced synthetic strategies, or as sorbents for more robust techniques like SPME and microextraction on packed sorbents, will add new horizons to explore the potential of MIPs in the field of plastic-derived xenoestrogens. This review presents various challenges, as well as progress and prospects associated with the extraction of plastic-derived phthalates and phenolic compounds using molecularly imprinted sorbents.     

环境样品中双酚类化合物的固相萃取研究进展

双酚类化合物作为一类内分泌干扰物广泛存在于环境介质中,经过多种途径迁移至人体后,可对人体产生内分泌毒性、细胞毒性、基因毒性、生殖毒性、二噁英毒性和神经毒性,已被加拿大政府风险评估识别为进一步优先控制名录。随着环境领域对双酚类化合物的广泛关注,相关研究工作逐渐向水、沉积物、灰尘和生物样品等多介质开拓。但是,由于不同环境样品在基质复杂性和污染物浓度水平等方面存在显著差异,开发提取效率高、净化选择性好、普适性强、操作简单、高通量的提取和净化方法,有助于实现环境介质中双酚类化合物的高灵敏、批量检测。近年来,新型前处理技术发展迅速,尤其是固相萃取技术,在双酚类化合物提取与净化方面取得了长足的发展,不仅在一定程度上克服了传统提取净化方法存在的耗时、耗力和耗溶剂等不足,而且为新型污染物分析提供了更多的技术支持。该文简述了典型双酚类化合物的理化性质、用途用量和环境危害,重点围绕新型固相萃取吸附剂开发和固相萃取模式转变两个方面,总结了固相萃取在双酚类化合物提取净化方法方面取得的进展。商品化固相萃取产品普适性强,在环境监测领域应用范围较广,适用于双酚类化合物的产品种类有限;新型吸附剂研发聚焦吸附容量(如介孔硅材料、碳纳米材料、金属-有机框架材料、环糊精)和选择性(如分子印迹聚合物和混合模式离子交换聚合物)两个方面,种类多样化可满足不同检测需求;越来越多的高灵敏分析仪器不断推向市场,为适应新的发展形势,固相萃取模式正逐渐向微型化、自动化、简易化等方向发展,如QuEChERS、固相微萃取、磁固相萃取等。     

液相微萃取-高效液相色谱联用分析化妆品中痕量的雌激素

建立了液相微萃取-高效液相色谱联用(LPME-HPLC)测定爽肤水中痕量的雌三醇、雌二醇、炔雌醇和雌酮的分析方法,研究了萃取溶剂种类、接受相体积、搅拌速度、萃取时间等对萃取效率的影响。结果表明,该方法对4种雌激素的富集倍数可达到247~343倍,方法的线性范围为1~200 μg/L,检出限为0.4~1.0 μg/L,6次平行测定的相对标准偏差为3.6%~7.3%,爽肤水中的加标回收率为101.2%~114.9%。方法简单快速、灵敏度高、环境友好,满足痕量雌激素分析的要求。     

Selective stationary phase for solid-phase microextraction analysis of sarin (GB)

A number of critical field applications require monitoring air samples for trace levels of chemical warfare agents. Solid-phase microextraction (SPME) is a convenient format to conduct these analyses. Measurements could be significantly improved if a SPME phase selective for nerve agents were substituted for non-selective polymers typically used (e.g., polydimethylsiloxane). This paper evaluates a novel stationary phase, previously developed for methylphosphonate sensor applications, for use with SPME sampling. The phenol-based polymer, BSP3, was found to offer far higher selectivity toward sarin (GB) than polydimethylsiloxane due to a pronounced affinity toward the target analyte and a lower affinity toward hydrocarbons.     

Analytical microextraction: current status and future trends

Analytical microextractions, defined as nonexhaustive sample preparation with a very small volume of extracting phase (microliter range or smaller) relative to the sample volume, represent an important development in the field of analytical chemistry. Analytes are extracted by a small volume of a solid or semi-solid polymeric material, as in solid-phase microextraction (SPME), or alternatively by a small volume of a liquid, as in liquid-phase microextraction (LPME). This paper gives an overview of the SPME and LPME techniques and discusses future trends. This includes a discussion of the different extraction formats available, commercial equipment, method transfer from traditional sample preparation methods to microextraction, and performance as well as robustness for the latter type of systems. In addition, the paper contains a unified approach to the understanding of extraction thermodynamics and kinetics applicable to both SPME and LPME.     

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。     

液相微萃取研究与应用

液相微萃取是近年来新兴的一种微型化样品前处理技术。该技术集萃取、净化、浓缩于一体,具有溶剂耗量少、成本低廉、操作便捷、精确和灵敏度高的特点。本文全面深入地综述了液相微萃取的各种工作模式及其原理和特点,阐述了相关的联用分析技术和方法的适用性,归纳和分析了影响萃取的主要影响因素及优化的方法,突出了上述几方面中具有发展潜力的新进展,包括各种动态萃取模式与装置、 与其它技术联用的新策略、离子液体作为萃取溶剂等,详细总结了近年来液相微萃取技术在环境、药物和食品等分析领域中的应用情况。     

离子液体在样品预处理中的应用

离子液体具有一些独特的物理和化学性质,作为一种可设计的绿色溶剂被应用于液液萃取、液相微萃取、固相微萃取和膜分离等样品预处理技术中。本文综述了离子液体在样品预处理中应用的研究进展。     

Carbon Nanotubes Coated Fiber for Solid‐Phase Microextraction of Bovine Fibrinogen and Bovine Serum Albumin

Carbon nanotubes (CNTs) are a kind of novel and interesting carbon material which can be used for separation and purification. In this investigation, commercial solid‐phase microextraction (SPME) fibers (PDMS) were coated with single‐wall nanotubes (SWNTs) and multi‐wall nanotubes (MWNTs) to study their adsorption and extraction ability of proteins, and bovine fibrinogen (BFg) and bovine serum albumin (BSA) were selected as the target proteins. While MWNTs adsorbed more BFg than SWNTs, SWNTs adsorbed more BSA than MWNTs. CNTs can selectively adsorb BFg in certain conditions. The fibers coated with CNTs had advantages over traditional SPME fibers in selectivity and sensitivity. It could be used to separate BFg in bovine blood plasma and also purify BFg from it. The results show that the selectivity, sensitivity and reproducibility of this method are good for real sample analysis.