Current Analytical Chemistry

ISSN: 1573-4110

Abstracts


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The Mass Spectrometric Analysis of Glycoproteins and their Glycan Structures
Willy Morelle and Jean-Claude Michalski

One of the most common post-translational modifications of proteins involves the covalent attachment of N- or O-linked carbohydrates to the protein. Glycan moieties are involved in a wide variety of intracellular, cell-cell and cell-matrix recognition events. The study of glycoprotein-linked carbohydrates remains one of the most challenging tasks given to biochemists and bioanalysts as these molecules can exhibit complex branched structures that can differ in linkage and the level of branching. This is why understanding how glycosylation affects the activities and functions of proteins in health and disease represents a major challenge. Mass spectrometry, is one of the most powerful and versatile techniques for the structural analysis of glycoconjugates. This review summarizes the state of knowledge for the mass spectrometric analysis of glycoproteins and their glycan structures.


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What’s New in Chromatographic Enantioseparations
Jacek Bojarski, Hassan Y. Aboul-Enein and Ashraf Ghanem

Progress in different areas of enantioselective chromatography and its applications in last years (2002-2003) is reviewed. Special attention is devoted to chromatographic enantioseparations of different drugs and natural compounds.


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Porphyrin Based Affinity Interactions: Analytical Applications with Special Reference to Open Tubular Capillary Electrochromatography
Zdenek Deyl, Ivan Miksik, Adam Eckhardt, Vaclav Kasickai and Vladimir Kral

This review offers a brief summary of results obtained from separations of the sets of biologically relevant compounds (carboxylic acids, amino acids, peptides, nucleotides and organic phosphates) using open tubular capillary electrochromatography (OT-CEC), in which oligopyrrolic macrocycles serve as the modifiers of the inner fused silica capillary wall surface. Types of interactions leading to improved selectivity of the open tubular capillary electrochromatographic systems and/or to the change of the speed of the electroosmotic flow are also discussed. In addition, selected comparative data on the application of oligopyrrolic macrocycles in other analytical methods, particularly chromatographic and spectrometric techniques, are presented.


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Current Methodology for Detection, Identification and Quantification of Genetically Modified Organisms
Marta Hernandez, David Rodriguez-Lazaro and Alejandro Ferrando

During recent years, arable land used for transgenic crops has undergone an exponential increase globally, and the tendency to augment not only the cultivated area but also the number of modified genetic traits is rather evident. However, public perception and confidence regarding genetically modified organisms (GMOs) have not paralleled this increase. Moreover, a general antipathy towards GMOs is nowadays detectable especially in Europe and there is an apparent lack of information for the consumer in many cases. To counterbalance the social alarm caused by the presence of GMO-derived ingredients in the commercial food chain, competent authorities have established appropriate regulations to guarantee the consumers’ right to information and choice. In this regard, several countries have established a strict labelling policy for products containing or derived from GMO. In order to achieve these labelling requirements different approaches have been taken with the aim of detection and quantification of the presence of GMO traces, using either protein- or DNA-based methods.

In this paper we review the different methodologies that are being applied to GMO studies. We describe the state-of-the-art instrumentation and technologies currently used, as well as the most recent advances in analytical systems for the detection, identification and quantification of GMOs. In addition to methodological considerations, important practical aspects such as the implementation of the analytical system into the food and feed chains will be considered. Finally, the importance of standardised/validated methods and future technological trends in the field are discussed.


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Recent Advances in Instrumentation for Gas Chromatography
Gwen M. Gross, Vanessa R. Reid and Robert E. Synovec

Since its introduction over 60 years ago, gas chromatography (GC) has become a cornerstone technique of analytical chemistry. While the basic components of a GC instrument have not changed since its introduction by Martin and James in 1952, instrumentation refinement has answered demands for faster, more sensitive and selective separations of complex samples. This review will discuss the advances made in GC instrumentation within the past few years as found in the literature, granted patents and commercial advances. The revival of older instrumentation techniques for current applications will also be discussed. Hardware advances discussed include new injection techniques, advances in heating technology (including resistive heating and two source heating for GC ovens) , with the largest volume of work being done in the development of new detectors. A brief discussion on commercially available portable GCs is also included. Advances in the realm of column technology, such as commercialization of high temperature silica capillaries and stationary phases stable to 480 oC, are also discussed. Novel GC stationary phase development has incorporated such materials as sol-gel poly(ethylene glycol), nanoparticles, ionic liquids, and co-polymers. Stationary phases are also discussed in relation to microfabricated GC, i.e. chip-based GC. The extensive work being completed in mGC is discussed herein, including column interfacial components for rapid heating, as well as sensitive and selective detection.


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Ultrasonication for Analytical Chemistry
J.L. Capelo and A.M. Mota

The purpose of this work is to present a peer revision to the last trends dealing with ultrasonication for sample treatment in Analytical Chemistry. The selective oxidation properties of sonication makes this tool a powerful help to distinguish, when present in solution, some metal organic species from the inorganic ones (organic mercury and inorganic mercury) or to differentiate in biological matrices non-toxic from toxic metal organic species (arsenobetaine from other toxic arseno-organic compounds). Moreover, with the recently developed multi-ultrasonicators sample throughput has been greatly increased. The development of glass probes has also led to avoid contamination from metals, which allows obtaining better quantification limits when working with metals such as Al. In very recent works the ultrasonication potential in conjunction with enzymes, has markedly enhanced the ability to extract metals from solid matrices with metal species preservation. This paper provides a fast approach to ultrasonication applications in Analytical Chemistry along with some useful recommendations in this field.


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Liquid Chromatography-Ion Trap-Mass Spectrometry and its Application to Determine Organic Contaminants in the Environment and Food
Vicente Andreu and Yolanda Picó

Recent experiences with liquid chromatography-quadrupole ion trap-mass spectrometry (LC-QITMS), as an analytical tool for determining trace amounts of organic contaminants in food and environmental samples, are addressed in this review. A brief introduction to the fundamental theory for quadrupole ion trap devices illustrates possibilities and limitations of this technique. Special attention is paid to the impact of sample preparation and chromatography on the ionization efficiency of analytes isolated from complex food and environmental matrices. The capacity to provide useful data for quantifying organic contaminants, and the possibility of obtaining structural information for identifying target and non-target compounds, are discussed. The flexibility, high sensitivity and multi-stage tandem mass spectrometric capability of the QIT are all illustrated. Contemporary applications of this technique to study organic contaminants in food and environment are presented.


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Protein Sequence and Structure Databases: A Review
Marcos J. Araúzo-Bravo and Shandar Ahmad

Several protein sequence and structure databases have emerged from a worldwide effort to curate the information on protein sequences and their structures. Sequences are written in different formats and certain standards have evolved. On the other hand, Protein Data Bank is the largest source of information on protein structures, and sets standards on the way structural information should be written. For handling large number of protein structures and sequences in bioinformatics, a thorough understanding of the formats and contents of these databases is required. In this review, we deal with some of the most common sequence and structure databases. Several protein structure databases have emerged, dealing with special issues and varieties of protein structures. We survey the contents and availability of different databases and review their classification and mutual linking. Certain quality and financial issues on these databases are also touched upon.


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Single Cell Proteomics: Challenge for Current Analytical Science
Bo Xu, Wei Du, Bi-Feng Liu and Qingming Luo

At present, proteomics that promises deep understanding of genomic functions is developing rapidly. Proteomics at single cell level represents new challenges that greatly call for technique innovation in current analytical chemistry. In this mini-review, the concept of single cell proteomics (SCP) is clarified. Recent advancement on strategy and methodology of SCP is reviewed, with emphasis on micro-separation technique improvement such as ultra-thin layer gel electrophoresis, multidimensional micro liquid chromatography and capillary electrophoresis, and microfluidic chip as well. Future development on SCP is also suggested.


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The Role of Atomic Spectrometric Techniques in the Determination of Chemical Elements in Atmospheric Aerosols
Patricia Smichowski, Darío Gómez and Griselda Polla

This review covers the application of atomic and mass spectrometric techniques for the determination of metals and metalloids in atmospheric aerosols. Atomic spectrometric methods based on flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS), atomic fluorescence spectrometry (AFS), total reflection X-ray fluorescence (TXRF) spectrometry and plasma based techniques such as inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) are reviewed, because a considerable amount of research is presently performed in this field. The application of atomic and mass spectrometric techniques for fractionation studies based on the use of chemical sequential extractions for metal partitioning in airborne particulate matter and fly ashes are also discussed. This survey contains; 156 references and covers mainly the literature published over the last decade.