Current Analytical Chemistry - Volume 1, Issue 1, 2005

This inaugural issue of Current Analytical Chemistry comprises a number of important reviews on the use of NMR spectroscopy for study of supra- and biomolecular systems, advances in head space gas chromatography, recent developments in chromatographic enantioseparations, ligand-exchange chromatography of amino acids, mass spectroscopic techniques for analysis of glycoproteins and glycans, open tubular electrochromatography and other exciting areas. It is hoped that “Current Analytical Chemistry” will soon emerge as the leading review journal in the field of analytical chemistry.

After the fields of liquid- and solid-state NMR spectroscopy have developed largely independently of each other over the past 50 years, materials of current interest call for new approaches which combine and merge spectroscopic techniques from either side. A particular possibility to promote NMR spectroscopy into this direction is provided by magic-angle sample spinning (MAS), which can be performed either at high speeds in solid-state NMR or at moderate speeds in combination with high-resolution NMR. In this way, new NMR methods and experiments have recently been developed, as will be discussed in this review. In solid-state NMR, new and versatile experiments are based on coherent spin-states and coherent transfer mechanisms, provided that fast MAS ensures efficient averaging of anisotropic interactions, and recoupling schemes selectively re-introduce the interactions of interest. In high-resolution NMR, MAS can be borrowed from solid-state NMR in order to ensure sufficient spectral resolution for samples with residual anisotropies or heterogeneities (so-called HRMAS). In such HRMAS studies, recoupling techniques become applicable and provide fully quantitative information on molecular structure and dynamics.

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.

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.

In this study, recent developments in headspace gas chromatography (HSGC) are briefly reviewed. Several novel HSGC techniques developed recently are presented in detail. These techniques were developed using the unique characteristics of the headspace sampling process implemented in commercial HSGC systems and therefore can be easily applied in laboratory and industrial practices. These techniques greatly expand the capability of traditional HSGC from simply analysis of volatile species to the measurements of nonvolatile species in solid systems and their properties in aqueous systems. The basic principles of the techniques along with specific applications are presented. These HSGC techniques are practical, accurate, and simple for both laboratory and industrial applications.

O-Benzyl-(S)-serine is a new selector for chiral ligand-exchange chromatography which has proved to be effective in the analytical separation of some natural and unnatural underivatized amino acids with fair to good separation and resolution factors. Both chiral mobile phase (CMP) and hydrophobically coated chiral stationary phase (CSP) approaches were successfully employed. A not completely clarified mechanism of chiral recognition is discussed.

This review critically discusses the most important properties of techniques applied to analyses for carotenoids and their impact on the reliability of the analytical results. The emphasis is placed on modern methods and the most recent references. Examples of analytical procedures illustrate the characteristics of experimental approaches to carotenoid analyses but no systematic survey of applications is given. Carotenoids are characterized chemically and their occurrence and functions in organisms are outlined. The principal implications of the (bio)chemical properties of carotenoids for the selection of an appropriate analytical procedure and for optimisation of the experimental conditions are dealt with. Various aspects of pretreatment and preconcentration of analytical samples are discussed, emphasizing modern approaches, such as microwave-assisted extraction or supercritical fluid extraction; the problems connected with chromatographic purification of carotenoids and with the obtaining of reliable standard materials are also dealt with. The approaches to determination of carotenoids involving high-performance separations are evaluated, emphasizing the importance of high performance liquid chromatography (HPLC) and capillary electrochromatography (CEC); of the detection techniques, spectrophotometry in ultraviolet and visible region (UV/VIS spectrophotometry), electrochemistry, thermal lens spectrometry (TLC), mass spectrometry (MS), nuclear magnetic resonance (NMR), and some aspects of vibrational spectrometry are primarily discussed.

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.