Recent progress of microfluidic sample preparation techniques

Sample preparation turns out to be one of the important procedures in complex sample analysis by affecting the accuracy, selectivity, and sensitivity of analytical results. However, the majority of the conventional sample preparation techniques still suffer from time-consuming and labor-intensive operations. These shortcomings can be addressed by reforming the sample preparation process in a microfluidic manner. Inheriting the advantages of rapid, high efficiency, low consumption, and easy integration, microfluidic sample preparation techniques receive increasing attention, including microfluidic phases separation, microfluidic field-assisted extraction, microfluidic membrane separation, and microfluidic chemical conversion. This review overviews the progress of microfluidic sample preparation techniques in the last 3 years based on more than 100 references, we highlight the implementation of typical sample preparation methods in the formats of microfluidics. Furthermore, the challenges and outlooks of the application of microfluidic sample preparation techniques are discussed.     

Recent advances in sample preparation techniques in China

Sample preparation is the procedure before instrumental analysis and significant to its effectiveness and efficiency. However, this procedure is usually time‐consuming, labor intensive, and prone to error. In the last decade, the development of sample preparation techniques has received increasing attention, especially in complex sample application. To pretreat samples faster and more effectively, advanced materials, instrumentation, and methods have been combined with typical techniques, including extraction, membrane separation, and chemical conversion techniques. Researchers in China focused on the development of simple, efficient sample preparation methods with selective enrichment and rapid separation capabilities for target analysis in complicated sample matrix and contribute almost a half of the publications in this specific field. In this review, a panorama of sample preparation techniques in China has been composed from more than 140 references, and we highlight some promising methods developed during recent years and introduce different separation materials with respect to these methods.     

Recent developments in sample preparation techniques for chromatography analysis of traditional Chinese medicines

Traditional Chinese medicines (TCMs) have a long history dating back thousands of years. Recently, there has been increasing interest worldwide in the use of TCMs for the prevention and treatment of various illnesses. In China, a large number of analytical tools, especially chromatographic techniques have been used to analyze the constituents of TCMs in order to control their quality and discover new bioactive compounds. In this paper, recent developments in sample preparation techniques for the extraction, clean-up, and concentration of analytes from TCMs are compared. These techniques include headspace solid-phase microextraction (HS-SPME), headspace liquid-phase microextraction (HS-LPME), microwave-assisted extraction (MAE), supercritical-fluid extraction (SFE), pressurized-liquid extraction (PLE), and microwave distillation (MD).     

Recent advances and trends in miniaturized sample preparation techniques

Advances in the area of sample preparation are significant and have been growing significantly in recent years. This initial step of the analysis is essential and must be carried out properly, consisting of a complicated procedure with multiple stages. Consequently, it corresponds to a potential source of errors and will determine, at the end of the process, either a satisfactory result or a fail. One of the advances in this field includes the miniaturization of extraction techniques based on the conventional sample preparation procedures such as liquid‐liquid extraction and solid‐phase extraction. These modern techniques have gained prominence in the face of traditional methods since they minimize the consumption of organic solvents and the sample volume. As another feature, it is possible to reuse the sorbents, and its coupling to chromatographic systems might be automated. The review will emphasize the main techniques based on liquid‐phase microextraction, as well as those based upon the use of sorbents. The first group includes currently popular techniques such as single drop microextraction, hollow fiber liquid‐phase microextraction, and dispersive liquid‐liquid microextraction. In the second group, solid‐phase microextraction techniques such as in‐tube solid‐phase microextraction, stir bar sorptive extraction, dispersive solid‐phase extraction, dispersive micro solid‐phase microextraction, and microextraction by packed sorbent are highlighted. These approaches, in common, aim the determination of analytes at low concentrations in complex matrices. This article describes some characteristics, recent advances, and trends on miniaturized sample preparation techniques, as well as their current applications in food, environmental, and bioanalysis fields.     

Recent advances in sample preparation techniques for effective bioanalytical methods

This paper reviews the recent developments in bioanalysis sample preparation techniques and gives an update on basic principles, theory, applications and possibilities for automation, and a comparative discussion on the advantages and limitation of each technique. Conventional liquid-liquid extraction (LLE), protein precipitation (PP) and solid-phase extraction (SPE) techniques are now been considered as methods of the past. The last decade has witnessed a rapid development of novel sample preparation techniques in bioanalysis. Developments in SPE techniques such as selective sorbents and in the overall approach to SPE, such as hybrid SPE and molecularly imprinted polymer SPE, have been addressed. Considerable literature has been published in the area of solid-phase micro-extraction and its different versions, e.g. stir bar sorptive extraction, and their application in the development of selective and sensitive bioanalytical methods. Techniques such as dispersive solid-phase extraction, disposable pipette extraction and micro-extraction by packed sorbent offer a variety of extraction phases and provide unique advantages to bioanalytical methods. On-line SPE utilizing column-switching techniques is rapidly gaining acceptance in bioanalytical applications. PP sample preparation techniques such as PP filter plates/tubes offer many advantages like removal of phospholipids and proteins in plasma/serum. Newer approaches to conventional LLE techniques (salting-out LLE) are also covered in this review article.     

Use of compressed fluids for sample preparation: food applications

This review attempts to provide an updated overview (including works published till June 2006) on the latest applications of compressed fluids as sample preparation techniques for food analysis. After a general review of the principles of supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE; also called accelerated solvent extraction, ASE or subcritical water extraction, SWE, when water is employed as extraction solvent), the principal applications of such techniques in the mentioned fields of food and natural products are described, discussing their main advantages and drawbacks.     

样品前处理技术在气相色谱分析中的应用进展

气相色谱法是当前应用最广泛的分析技术之一。使用气相色谱对复杂基体进行分析时的样品前处理步骤往往繁琐耗时,易引起误差,已成为制约分析效率和准确度提升的关键环节。本文综述了2009-2013年几种主要的样品前处理技术,包括吹扫捕集、固相萃取、固相微萃取、液相微萃取技术以及微波辅助萃取、超声波辅助萃取等场辅助萃取技术在气相色谱分析中的应用研究进展。     

样品前处理-色谱分析在线联用技术的研究进展

样品前处理是色谱分析中耗时最多、最容易引起误差的关键环节,因此有关样品前处理技术与色谱分析的在线联用的研究已成为分析化学的前沿课题。本文综述了近年来各种样品前处理技术与色谱分析在线联用的研究进展,包括固相萃取、固相微萃取与液相微萃取、膜辅助萃取、场作用辅助萃取、气相萃取、热解吸以及微芯片分离技术。     

固相萃取技术在食品痕量残留和污染分析中的应用

食品痕量残留和污染分析中,样品的前处理极为重要,也是其难点所在。由于食品和农产品样品的多样性和复杂性,目前还没有一种前处理技术能够适合所有情况下的所有样品。本文对近年来发展起来的新型固相萃取技术如固相微萃取、搅拌棒吸附萃取、基质固相分散萃取、分子印迹固相萃取、免疫亲和固相萃取、整体柱固相萃取、碳纳米管固相萃取等在食品痕量残留和污染分析中的应用进行了综述,对未来的发展前景作了展望。     

微孔有机聚合物在样品前处理技术中应用的研究进展

微孔有机聚合物（microporous organic polymers,MOPs）是一类由轻元素组成的新型多孔材料,具有骨架密度低、比表面积大、孔尺寸可调控、表面可修饰、化学和物理性质稳定等优点。近年来,MOPs在样品前处理领域展现出巨大的应用潜力。本文综述了MOPs的结构类型及合成方法,以及MOPs在固相萃取、批处理吸附萃取、整体柱和传感膜等样品前处理技术中的应用。     

色谱分析中样品前处理技术的发展动态

作为现代分析领域的重要手段之一,色谱可用于食品、环境、生物等复杂样品的定性与定量分析。而样品前处理是获得理想色谱分析结果的必要前提,它可有效消除基质干扰、浓缩目标分析物、改善分离效能以及延长色谱仪器使用寿命。本文主要依据2020年4-5月Anal Chem新发表和在线录用的有关论文,讨论色谱分析中涉及样品前处理技术方面的最新发展动态。     

Recent developments in sample preparation for chromatographic analysis of carbohydrates

Carbohydrates are a very important group of compounds due to their roles as structural materials, sources of energy, biological functions and environmental analytes; they are characterized by their structural diversity and the high number of isomers they present. While many advances have been made in carbohydrate analysis, the sample preparation remains difficult. This review aims to summarize the most important treatments which have been recently developed to be applied prior to the analysis of carbohydrates by chromatographic techniques. Due to the multiplicity of structures and matrices, many different techniques are required for clean-up, fractionation and derivatization. A number of new techniques which could be potentially adequate for carbohydrate characterization have also been revised.     

Recent developments and applications of microextraction techniques in drug analysis

Sample preparation is important for isolating desired components from complex matrices and greatly influences their reliable and accurate analysis. Recent trends in sample preparation include miniaturization, automation, high-throughput performance, online coupling with analytical instruments, and low-cost operation through extremely low or no solvent consumption. Microextraction techniques, such as liquid-phase microextraction and solid-phase microextraction, have these advantages over the traditional approaches of liquid–liquid extraction and conventional solid-phase extraction. This review focuses primarily on these microextraction techniques developed over the last decade, and presents a summary of the characteristics of various approaches in drug analysis.     

基于色谱-质谱联用的脂质分析样品前处理技术研究进展

脂质作为细胞膜和亚细胞膜的主要结构成分,在能量来源、细胞信号传导等多种生物学过程中发挥着重要作用。近年来,脂质分析受到越来越多的关注,其中色谱-质谱联用技术在脂质分析中占据主导地位。由于样品基质复杂,样品前处理有富集痕量物质和减少基质干扰的作用,成为脂质分析中的一个关键步骤。该文综述了近年来基于色谱-质谱联用技术的脂质分析中样品前处理技术的研究进展和应用,对各种样品前处理技术进行了阐述和总结。基于液相的萃取方法有液-液萃取和单一有机溶剂萃取。基于固相的萃取方法包括固相萃取和固相微萃取。场辅助萃取方法包括超临界流体萃取、加压流体萃取、微波辅助萃取和超声辅助萃取。此外,还介绍了在线联用样品前处理方法和用于活体分析的样品前处理方法。最后,对基于色谱-质谱联用的脂质分析样品前处理技术存在的问题及发展趋势进行了探讨。样品前处理技术的发展将提高脂质分析的灵敏度、选择性和分析速度。     

Reproducibility of radioactive sample preparation techniques

The reproducibility of samples prepared for the determination of radioactivity has been investigated for a low-energy beta-emitting nuclide, a high-energy beta-emitting nuclide, and a gamma-emitting nuclide.Variables studied, in addition to the nature of the nuclide, were; the total solid concentration in solution, the nature of the sample mount, the pH value of the solution, the use of auxiliary porous media (paper), and the effect of a wetting agent.High total solid concentration had a great effect on the reproducibility of measurements made with the low energy beta-emitter, and a less pronouced effect on measurements made with the high energy beta-emitter. The effect of total solids was negligible for measurements of the gamma-emitter using a single-channel scintillation spectrometer.Copper or aluminum planchets gave best reproducibility for the beta-emitting nuclides, whereas copper planchets or steel cups were best for the gamma-emitter.The effect of the other factors studied was negligible under conditions of this investigation.     

分子印迹样品前处理技术的研究进展

样品前处理是分析过程的关键环节,直接影响着分析结果的准确度和精密度．分子印迹聚合物具有特异性识别能力,能从复杂样品中选择性分离富集目标物,在复杂样品前处理领域中有重要的发展潜力和应用前景．本文综述了近年来分子印迹样品前处理技术的研究进展,包括分子印迹固相萃取、分子印迹固相微萃取、分子印迹膜萃取等样品前处理技术．     

Recent applications of thermal lens spectrometry in food analysis and environmental research

This review summarizes the most recent achievements related to the application of thermal lens spectrometry (TLS) in food analysis and environmental research. All the applications are associated with the use of an appropriate analytical procedure providing sufficient selectivity, that cannot be achieved by TLS itself. Several selective reagents, biosensors and chromatographic separation procedures (IC, HPLC), used for this purpose, and their performance in combination with TLS, are described. Heavy metals and related species, pesticides, carotenoids, fatty acids, and their determination in samples such as water, fruit juices, oils and marine phytoplankton were given most consideration. The main advantages of novel analytical methods include improved sensitivity and selectivity, simplicity, minimized need for sample preparation and handling as well as reduced time of analysis.