Developments in the use of soluble ionic polymers as pseudo-stationary phases for electrokinetic chromatography and stationary phases for electrochromatography

This article reviews the development, characterization and application of soluble ionic polymeric materials as pseudo-stationary phases for electrokinetic chromatography and as stationary phases for electrochromatography since 1997. Polymeric pseudo-stationary phases for electrokinetic chromatography, including cationic polymers, anionic siloxane and acrylamide polymers, polymerized surfactants (micelle polymers), and chiral polymers are reviewed. Also reviewed are suspended molecularly imprinted polymer micro-particles. Application of polymeric pseudo-stationary phases with electrospray ionization mass spectrometric detection is presented. Recent progress in the development and characterization of physically adsorbed stationary phases for electrochromatography using polymers of the same or similar chemistry is also reviewed.     

Qualification and validation of software and computer systems in laboratories

 Installation and operational qualification are important steps in the overall validation and qualification process for software and computer systems. This article guides users of such systems step by step through the installation and operational qualification procedures. It provides guidelines on what should be tested and documented during installation prior to routine use. The author also presents procedures for the qualification of software using chromatographic data systems and a network server for central archiving as examples. Received: 31 October 1997 · Accepted: 25 November 1997     

Some cluster and condensed-phase properties of light elements: B to P

Attention is first drawn to disordered condensed phases of Si and C. Amorphous Si, with clear-cut tetrahedral coordination, is treated by combining sp³ hybridization with a random network model of structure, X-ray and electron diffraction experiments confirm both electron density and structural models. Recent work using the Car-Parrinello technique is then reviewed, with the aim of comparing and contrasting amorphous C and Si and their liquid phases. After a brief review of the structure and bonding in clusters of Al and P atoms, some results on clusters of Na are presented and related to cohesion in the condensed metallic phase. Then, fission of doubly charged Na clusters is treated at some length and, in particular, is related to quantum chemical procedures. A short summary concerning π-bands in graphitic and boron nitride layers is followed by a discussion of BN alternants, both buckytubes and octahedral symmetry cages being considered, along with C analogs. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 695–707, 1997     

Hydride-based silica stationary phases for HPLC: fundamental properties and applications

Silica hydride is a recent development in chromatographic support materials for HPLC where hydride groups replace 95% of the silanols on the surface. This conversion changes many of the fundamental properties of the material as well as the bonded stationary phases that are the result of further chemical modification of the hydride surface. The general approach for fabricating the silica hydride and subsequent bonded phases is reviewed. Properties of the silica hydride surface are compared to those of the standard material obtained in the preparation of most commercial HPLC stationary phases. Some unique chromatographic properties of hydride-based phases are described as well as some general application areas where these bonded materials may be used in preference to or have advantages not available from typical stationary phases.     

Development and applications of industrial process analyzers

Contacts between users and suppliers is essential to ensure cost-effectiveness of process analyzers. Technical consideration of in-line, on-line and off-line measurements as well as analytical procedures are needed for selection of the most appropriate system. Quantitative performance specifications are often set too high, resulting in a sophisticated analyzer with excessive investment and maintenance costs. Process parameters such as time constant, sampling point and environmental conditions must be considered. Rules for decision-making are reviewed; autocorrelation, cross-correlation, controllability and information theory are useful in making efficient decisions on appropriate analyzers. Examples related to sulphur dioxide in stack gas scrubbers, chlorine in water supplies and sodium in boiler feed water are discussed.     

Recent developments in adsorption liquid chromatography (NP-HPLC) A review

The development of normal phase chromatography mainly in the past ten years is summarized. At first, the difference between normal-phase and reversed-phase chromatography is briefly discussed. According to Snyders theory of retention, some theoretical considerations are added. Most of the stationary phases synthesized in the past years and their field of use in NP-LC are given. They are sorted by linkage to silica and by their polar substituents. The effects resulting from variation of phases and eluents are discussed. Examples for group separation and other applications of NP-LC are given. Received: 10 December 1997 / Revised: 24 February 1998 / Accepted: 26 February 1998     

Recent developments in adsorption liquid chromatography (NP-HPLC) A review

The development of normal phase chromatography mainly in the past ten years is summarized. At first, the difference between normal-phase and reversed-phase chromatography is briefly discussed. According to Snyders theory of retention, some theoretical considerations are added. Most of the stationary phases synthesized in the past years and their field of use in NP-LC are given. They are sorted by linkage to silica and by their polar substituents. The effects resulting from variation of phases and eluents are discussed. Examples for group separation and other applications of NP-LC are given. Received: 10 December 1997 / Revised: 24 February 1998 / Accepted: 26 February 1998     

Network computing: the Hartree-Fock calculation as a model

Distributed computation over local and wide-area networks is gaining importance and may soon become the primary means in high performance computing. The development in all areas of scientific computing is closely coupled with the development of efficient application software that fully utilizes the power of the modern computer resources. In numerical quantum chemistry, the adaptation of method and program development to parallel and distributed-parallel computing has shown remarkable results. The contributions of Jan Alml?f in this area of research are briefly reviewed in this paper. The integral-direct Hartree-Fock calculation (zeroth, first and second derivatives) will be used as a model to investigate network-computing techniques and paradigms. Received: 2 February 1997 / Accepted: 24 March 1997     

Quality assurance in immunogenetics and histocompatibility: experience with EFI Accreditation

 The European Federation for Immunogenetics (EFI) has its own standards for histocompatibility testing. Compared with EN 45001 and ISO Standards, EFI Standards are more detailed, actually stating "what to do" in the laboratory. The decision of Eurotransplant that all its organ transplantation programmes must be EFI-accredited by the year 2000, illustrates the importance of the these standards. It took us 11 months to prepare the EFI questionnaire, describing the main features of our laboratory and how they complied with EFI Standards. After approval of this file, inspection was performed by a team of two peers who routinely worked in an EFI-accredited tissue typing laboratory. The pre-analytical, analytical and post-analytical phases were inspected during a one day visit. Furthermore, a checklist was reviewed against the laboratory's documentation system. Within 1 month of reception of the inspection report, we were expected to send a reply listing the corrective actions taken. Upon acknowledgement of the latter, EFI Accreditation was granted, for 1 year. We feel that detailed standards, specifically designed for a certain type of laboratory, offer many advantages. Received: 15 April 2000 · Accepted: 15 April 2000     

Proteomics: applications and opportunities in preclinical drug development

Advances in DNA sequencing and the near-term availability of whole genome sequences for several pharmaceutically relevant organisms promise to dramatically alter the breadth and scale of high-throughput proteomic studies. The substantial amount of literature is available in the public domain, demonstrate the potential of proteomics in the preclinical phases of pharmaceutical development. Over the next few years, it is anticipated that functional genomics and proteomics will have major impacts on the clinical phases of drug development. Expected benefits are earlier proof-of-concept studies in man and increased efficiency of clinical trials through the availability of biologically relevant markers for drug efficacy and safety.     

Le vaporeformage catalytique : application a la production embarquee d'hydrogene a partir d'hydrocarbures ou d'alcools

Catalytic steam reforming : Use for on-board hydrogen production from hydrocarbons or alcohols. To identify the challenges in the development of electrical vehicles, literature was rapidly reviewed. Research on hydrogen production processes suitable for fuel cell applications is a major challenge. Catalytic steam reforming of hydrocarbons as well as alcohol is a very promising route. The choice of ethanol and supported rhodium catalysts will be justified in the light of ethanol physico-chemical properties, reaction mechanism, cerium-based oxides characteristics and the specifications imposed by fuel cell applications.     

Recent progress in the development,characterization and application of polymeric pseudophases for electrokinetic chromatography

This review article details the development, characterization and application of polymeric materials as pseudostationary phases for electrokinetic chromatography over the past two years. Recent developments in cationic polymers and anionic siloxane, acrylamide and polymerized surfactants (micelle polymers) are reviewed. Also reviewed is recent progress in the development and characterization of chiral polymeric phases for chiral separations by electrokinetic chromatography, and application of a polymeric pseudophase with electrospray ionization mass spectrometric detection.     

Microemulsion microstructure and interfacial curvature

The typical phase behavior of microemulsion systems undergoing phase inversion is briefly reviewed. As a model system H₂O-n-octane-C₁₂E₅ is studied with various experimental techniques. The occurring microstructures are visualized by freeze fracture electron microscopy and the corresponding domain sizes are quantified by small-angle neutron scattering. From the variations of the domain sizes the mean and Gaussian curvatures of the interfacial film with temperature are determined. It is found that the mean interfacial curvatureH changes gradually and nearly linearly with temperature from positive (Winsor I) to negative (Winsor II), passing through zero for bicontinuous microemulsions where these contain exactly equal volume fractions of water and oil. There the interfacial tension between bulk water-and oil-rich phases passes through an extreme minimum. Quantitative knowledge of the curvatures permits the measurements of interfacial tensions between the bulk phases to be discussed in terms of the relative contributions of bending energy and entropy of dispersion.     

Lyotropic and thermotropic behavior of Alkylglucosides and related compounds

 The phase diagram of the binary system composed of octyl-β-D-glucopyranoside and water was investigated and the phase boundaries were determined. Polarising optical microscopy was used to define the different phases, proton and deuterium NMR experiments to define the region of existence of the different phases and to obtain information on axiality and head group solvation. DSC experiments were performed to determine the thermal transitions from solid to thermotropic liquid crystals for octyl-β-D-gluco-pyranoside, the related alkylglucosides or maltosides, and to gain information on the role played by sugar units in the thermodynamics of such phase transitions. Received: 15 May 1997 Accepted: 08 September 1997     

亲水作用色谱固定相及其在中药分离中的应用

亲水作用色谱(HILIC)作为一种分离极性化合物的液相色谱模式,近年来越来越受到关注和重视。一方面是因为强极性化合物的分离问题引起了各个研究领域的重视,如药物分析、代谢组学、蛋白质组学等研究领域都不同程度地涉及强极性化合物的分离问题;另一方面是由于HILIC具有流动相组成简单、分离效率较高、与质谱兼容以及反压较低等优势。固定相是HILIC发展和应用的基础,本文主要从固定相分子结构的角度对HILIC固定相的结构特征、保留特性以及应用概况等进行了综述。对传统正相色谱固定相用于HILIC以及专门设计的HILIC固定相进行了介绍,评述了各自的优缺点和应用概况;对近年来HILIC固定相在中药分离中的应用进行了介绍;并对HILIC固定相的发展进行了展望。     

八种冠醚固定液的McReynolds常数的研究

冠醚在气相色谱分析中的应用研究已有论文发表。本文测定了八种冠醚固定液的McReynolds常数,并讨论了它们的色谱性质。 1 实验 1.1 主要仪器与试剂 103气相色谱仪,上海分析仪器厂,φ4×1 000 mm不锈钢柱;电子秒表(±0.01 s);Chromosorb G-AW-DMCS(60～80目,美国);正构烷烃,     

Hydride-Based Separation Materials for High Performance Liquid Chromatography and Open Tubular Capillary Electrochromatography

 Silica hydride is a recent development in chromatographic support materials for high performance liquid chromatography (HPLC) where hydride groups replace 95% of the silanols on the surface. This conversion changes many of the fundamental properties of the material as well as the bonded stationary phases that are the result of further chemical modification of the hydride surface. Some unique chromatographic properties of hydride-based phases are described as well as some general application areas where these bonded materials may be used in preference to or have advantages not available from typical stationary phases. The fabrication, properties and applications of etched chemically modified capillaries for electrophoretic analysis are also reviewed. It is shown that the etching process creates a surface that is fundamentally different than a bare fused silica capillary. The new surface matrix produces unique electroosmotic flow properties and is more compatible with basic and biological compounds. After chemical modification of the surface, the bonded organic moiety (stationary phase) contributes to the control of migration of solutes in the capillary. Both electrophoretic and chromatographic processes take place in the etched chemically modified capillaries leading to a variety of experimental variables that can be used to optimize separations. A number of examples of separations on these capillaries are described.     

The TB-LMTO method and its relation to the screened KKR method

The main formal aspects of the TB-LMTO and the screened KKR method are reviewed in terms of multiple scattering theory (scattered wave method) as based on a general reference medium. In terms of the corresponding Green's functions, a comparison is made between these two approaches listing similarities and differences and advantages and disadvantages. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 165–188, 1997     

含极性基团的硅质高效液相色谱固定相

介绍了含极性基团硅质高效液相色谱固定相的研究进展,对反相固定相的合成、极性基团作用机理和色谱性质方面作了评述,对手性分离固定相和高效离子色谱固定相方面的进展也作了简单综述。