Miniaturized sample preparation combined with liquid phase separations

Miniaturized sample preparation methods designed as the sample pretreatment for liquid phase separations, such as liquid chromatography, capillary electrophoresis and capillary electrochromatography, have been reviewed especially for the on-line coupling of the sample preparation process and the separation process. The development of the desorption interfaces for the effective combining of the sample preparation and subsequent liquid phase separations is briefly described along with the applications of the combined analytical systems to the analysis of complex sample mixtures such as biological and environmental matrices. Novel use of fine polymeric filaments as the extraction medium for microscale liquid phase separation methods are investigated and a comparison is made with other sample preparation techniques. Polymer coating onto the fibrous material is also introduced to further develop microscale sample preparation methods with improved extraction performance. Several other microscale sample preparation methods having a potential compatibility to the liquid phase separations are also described for future applications of these techniques.     

Modern Sample Preparation Methods in Chemical Analysis

 The choice of the sample preparation method is crucial in chemical analysis, since it is often the most critical and time-consuming step of an analytical process. Some of the older methods are laborious, expensive, and offer no scope for automation. The newer sample preparation techniques can give higher yields, better sample clean-up, cost effectiveness worker safety and environmental protection. Some novel sample preparation methods are described their potential is illustrated with emphasis on bioanalytical applications.     

Solvent-free MALDI-MS for the analysis of biological samples via a mini-ball mill approach

An efficient, low sample load mini-ball mill (MBM) sample preparation procedure was developed for solvent-free MALDI analysis of peptides and proteins. Picomole sample amounts can be handled conveniently, with 30 s grinding times being sufficient. Matrix purity and molar analyte/matrix ratios are not as critical as with methods employing solvent. Ammonium salt is employed for protonation of the peptide and suppression of sodiation. This strategy allows for peptide mapping and other biochemical manipulations to be performed prior to MBM sample preparation and mass analysis. The analysis of bovine serum albumin (66 kDa) yielded good results, indicating that higher molecular weight proteins are accessible. A semi-solvent-free strategy by the MBM sample preparation method is also described.     

纳米晶双相稀土永磁合金透射电镜薄膜样品的制备

探讨了纳米晶双相稀土永磁合金在ＰＴＦＥ夹具园片抛光法和在离子薄化技术中的电镜薄膜样品的制备,比较了利用离子薄化和电解双喷加离子薄化技术获得的纳米晶双相稀土永磁合金的透射电分析结果,优化了两种方法制备电镜薄膜样品的实验条件及参数范围。探索出较佳的有竽透电镜观察的纳米双相稀土永磁合金薄膜样品的制备方法。     

On-line sample preparation for high throughput reversed-phase LC/MS analysis of combinatorial chemistry libraries

An on-line sample preparation method utilizing a time-programmed autosampler is described for high throughput liquid chromatography/mass spectrometry (LC/MS). This approach is particularly helpful for the LC/MS analysis of samples which require solvents incompatible with HPLC in the sample preparation process. The on-line sample preparation approach minimizes a bottleneck in throughput and improves sample recovery under some circumstances.     

Electrochemical Sample Preparation for the Voltammetric Determination of Heavy-Metal Ions in Wine

An original, simple, and rapid method consuming little labor and eliminating the contamination of a sample and the loss of analytes is proposed for the electrochemical preparation of wine samples. The time of electrochemical sample preparation (ECSP) is no longer than 10 min. A four-electrode single-compartment electrolyzer allows all stages of voltammetric analysis (electrochemical sample preparation, electrochemical preconcentration and determination) to be carried out continuously. The processes occurring at electrodes at different stages of analysis are described. The concentrations of heavy metals determined in wines by stripping voltammetry (SVA) and atomic absorption spectroscopy (AAS) are compared.     

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。     

聚丙烯酰胺电泳法测定小麦种子纯度方法的改进

使用SE-2000A型对小麦、玉米专用的电泳仪，对GB/T3543.5-1995聚丙烯酰胺电泳法测定小麦种子纯度方法的样品提取、点样量及电泳条件进行了改进，结果表明：改进后使麦醇蛋白溶蛋白电泳图谱的蛋白质区带界限更明显，公共带和特征带清晰、可靠，且样品提取时间缩短了23.5h。     

Automated sequential trace enrichment of dialysates and robotics. A technique for the preparation of biological samples prior to high-performance liquid chromatography

The development of the sample preparation process, the automated sequential trace enrichment of dialysates, in association with a cartesian robotic sampler is described. The system has been applied to the total automation of the preparation of biological samples and high-performance liquid chromatographic analysis. Concepts of the technique are reported together with an examination of its application to free and total analyte estimation. Examples of chromatographic separations obtained from the preparation of a variety of different analytes and sample materials are given.     

Present-day methods for the determination of trace elements in oil and its fractions

The development and use of instrumental methods for the determination of a wide range of trace elements in oil is considered. Special attention is paid to methods of the direct introduction of samples into spectrometers. It is shown that preliminary sample preparation is in certain cases necessary for the determination of trace elements in oil. The main methods of sample preparation of oils, including methods of extraction of a series of trace elements from crude oil (extraction, membrane, sorption, etc.), are described.     

Nondigest liberation of biomarkers from plasma: a novel two-stage ultrafiltration approach

A simple procedure for sample preparation of human plasma by two stages of ultrafiltration using one device is described. Our approach is useful for nondigest liberation of biomarkers bound to albumin and other plasma proteins. The analyte contained in the ultrafiltrate can be directly analyzed without additional sample preparation, and quantified by 2-D RP-RP LC/MS.     

Environmental Sample Pretreatment with Microwave-Assisted Techniques

In many analytical laboratories, the microwave-assisted dissolution technique is already the method of choice for sample preparation. Other microwave-assisted techniques for sample preparation are being constantly developed and put into practice. The application of microwave energy for the isolation of organic analytes from diverse environmental samples began in mid eighties and has made great progress in recent years. In this work, the microwave-assisted extraction (MAE),the microwave-assisted saponification (MAS) and the microwave-assisted alkaline degradation (MAAD) of organic compounds in various synthetic and real environmental samples are described.     

Automated MALDI-TOF-MS sample preparation in combinatorial polymer research

A new automated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) sample spotting technique that allows the integration of MALDI sample preparation in the workflow of combinatorial polymer research is described. The technique is performed utilizing a commercially available synthetic robot and was first evaluated with polymer standards of known composition and later on used for the monitoring of the living cationic ring-opening polymerization of 2-ethyl-2-oxazoline. The spotting was carried out as a multiple layer approach, which offers the ability of complex sample preparation without the requirement of premixing the different components. The described technique reduces the time required for sample preparation and offers the possibility of automated sample spotting during polymerization reactions performed in a synthetic robot. This allows the integration of molecular weight screening and polymer end/group determination utilizing MALDI-TOF-MS as a high-throughput tool in combinatorial polymer research.     

Ionic liquids in sample preparation

Due to their unique properties, their good extractabilities for various target analytes, and the fact that many compounds are highly soluble in them, room-temperature ionic liquids (ILs) are used as promising alternatives to the traditional organic solvents employed in sample preparation. ILs have been used as extraction solvents for a wide range of analytes, from environmental contaminates to biomacromolecules and nanomaterials, and as dissolution solvents for various detection techniques. In this paper, the main applications of ILs in sample preparation are reviewed, and the problems and challenges in this area are described.     

Advances in the thin-layer chromatographic forensic analysis of inks

Advances in the use of thin layer and high-performance thin-layer chromatography for analysis of inks and ink writings in forensic investigations are reviewed. Experimental materials and techniques such as sample preparation, layers, sample application, development, detection, documentation, and interpretation of results are described and selected applications for several ink types are given. Some additional analytical techniques that complement thin-layer chromatography are also mentioned. Citations to important literature, from 2008 to 2016, are included.     

Acoustic levitation device for sample pretreatment in microanalysis and trace analysis

A sample preparation device for microanalysis and trace analysis based on acoustic levitation is described. Derivatization can be performed in a single levitated drop as part of the sample pretreatment in an analytical procedure. The applicability of the experimental setup is demonstrated. First results of the preconcentration of hexachlorobenzene are given.     

Automated multiple-layer spotting for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of synthetic polymers utilizing ink-jet printing technology

Recently, a new multiple-layer matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) sample spotting technique for poly(ethylene glycol), offering improved analysis possibilities, was described. In this contribution the application of ink-jet printing to automated, multiple-layer MALDI-TOFMS sample preparation of synthetic polymers is presented, allowing accurate deposition of matrix, additive and analyte solutions. The new sample preparation technique was evaluated for poly(ethylene glycol) as well as poly(methyl methacrylate) standards, and optimized settings for both synthetic polymers have been obtained.     

磁性纳米材料在样品前处理中的应用进展与展望

在样品前处理技术中,吸附剂材料起关键作用。随着纳米材料的发展,越来越多的纳米材料被用作吸附剂以提高对目标物的萃取效率。磁性纳米材料因其具有易于分离、表面可修饰、吸附能力强和良好的生物相容性等优异性能,已广泛应用于分析方法的样品前处理技术中。该文通过对磁性纳米材料在磁性固相萃取和在其他样品前处理技术中的研究与应用展开总结和论述,对磁性纳米材料的稳定性、作用力、比表面积及孔径调控的制备进行了阐述,展望了磁性纳米材料在分离科学中的应用前景,为进一步研究磁性纳米材料的应用提供了参考。     

Use of computerized pattern recognition in the study of the cuticular hydrocarbons of imported fire ants. I. Introduction and characterization of the cuticular hydrocarbon patterns of Solenopsis invicta and S. richteri

A method is described in which gas chromatographic (GC) data obtained from cuticular hydrocarbons are treated by methods of pattern recognition. Based on a recently described sample preparation procedure, GC data are normalized to eliminate slight variations in chromatographic conditions and converted into the proper format for discriminant analysis by computer. The results of several methods of data treatment and display are discussed, based upon the chemometric system package, ARTHUR. The approach has the advantage of largely removing operator bias.