Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2008-2010)

Capillary electrophoresis has been alive for over two decades now; yet, its sensitivity is still regarded as being inferior to that of more traditional methods of separation such as HPLC. As such, it is unsurprising that overcoming this issue still generates much scientific interest. This review continues to update this series of reviews, first published in Electrophoresis in 2007, with an update published in 2009 and covers material published through to June 2010. It includes developments in the fields of stacking, covering all methods from field-amplified sample stacking and large volume sample stacking, through to ITP, dynamic pH junction and sweeping. Attention is also given to on-line or in-line extraction methods that have been used for electrophoresis.     

Imidazolium Based Probes for Recognition of Biologically and Medically Relevant Anions

The imidazolium derivatives due to their positive charge possess one of the most polarized and positively charged proton at C2‐H to form strong ionic hydrogen bond (also termed as double ionic hydrogen bond) with anions and also provide opportunities for anion – π interactions with electron‐deficient imidazolium ring. In the present review article, imidazolium based molecular probes for their ability to recognize inorganic anions like halides, cyanide, perchlorate, carboxylic acids, phosphate, sulfate etc. and their derived molecules viz. nucleotides, DNA, RNA, surfactants, proteins, etc have been discussed. The review covers the literature published after year 2009 and has > 130 references. The previous literature has already been discussed by Yoon et al. in two review articles published in Chem. Soc. Rev. 2006 and 2010.     

合成不同拓扑结构聚合物的一个简便策略

随着高分子化学的进步, 特别是可控自由基聚合反应的发现, 不同拓扑结构聚合物的合成己获得了巨大的进展. 为合成这些复杂结构的聚合物, 人们成功地研究了不同的聚合方法. 其中, 不同功能团引发剂方法是较为方便和可行的方法之一, 并且已广泛用于不同结构聚合物的合成. 本文综述了用该方法合成不同拓扑结构聚合物, 包括嵌段、杂臂星形、H-形、π-形、接枝和环状聚合物所取得的进展, 特别强调的是这篇论文没有覆盖这方面的所有研究工作. 这一合成方法的思路是基于将不同聚合反应, 尤其是不同可控聚合反应相结合, 或者将可控聚合与不同的偶合反应, 例如与点击反应、Diel-Alder反应和活性酯反应等相结合. 所讨论的多功能引发剂不仅包括小分子化合物, 也包括带有两个和两个以上引发基团或链转移基团的聚合物. 后者称为大分子多功能团引发剂, 可以独立引发不同的聚合反应.     

Trace element speciation using solid phase microextraction

An initial review of research targeting applications of solid phase microextraction for organometallic speciation, published in 2001, encompassed literature from the early days of solid phase microextraction up to June 2000. In this article, the reader will find a compilation and discussion of relevant literature published from June 2000 to December 2004. Because of the maturity of the technique, only a brief overview of the measurement principles is presented. The major thrust of the article highlights applications of solid phase microextraction to the fields of elemental and organometallic analyses. In contrast to the earlier review, applications related to the determination of phosphorus-, sulfur-, bromine-, chlorine- and iodine-containing compounds have also been included for those cases where the target of the determination is the element or a specific molecule containing the element for which atomic spectroscopy has been advocated as a detection technique. Additionally, other microextraction techniques are also considered, including stirbar sorptive extraction and single droplet microextraction.     

Quantification of fexofenadine in biological matrices: a review of bioanalytical methods

Fexofenadine (FEX) has been extensively used for therapeutic benefits after the market withdrawal of terfenadine. Recently, the popularity of FEX has emerged owing to its unique disposition via drug transporters and, hence, it has been used as a model probe for both in vitro and in vivo investigations to understand mechanistic aspects of drug-drug interactions (DDI). Going hand in hand with the increased use of FEX in therapy and research, numerous bioanalytical methods for FEX have been published. The various published bioanalytical methods for FEX are collated in this review to provide a comprehensive information on extraction methodology, assay conditions, chromatography and detection systems. Generally, the published methods have been adequately validated and can be readily used to support the use of FEX in pharmcokinetic, DDI and mechanistic investigations.     

Applications of coupled LC-GC: A review

Although coupled liquid chromatographygas chromatography (LC-GC) was first demonstrated ten years ago, only in the last few years has there been a sudden surge of interest in the technique. Approximately 70% of the total number of LC-GC applications have been published in the last two years (1987–88) alone. This review categorizes LC-GC publications into four main application areas: fossil fuels, foods, environmental samples, biologiical/pharmaceutical samples, and miscellaneous samples. Multidimensional separations carried out using other coupled-column chromatographic techniques (such as supercritical fluid chromatography (SFC) with GC, and on-line trace enrichment-GC) have also been included in this review.     

Current Applications of Suzuki–Miyaura Coupling Reaction in The Total Synthesis of Natural Products: An update

Suzuki‐Miyaura Coupling Reaction (SMCR) has been extensively used in the total synthesis of natural products. We underscored these achievements in a report published in Tetrahedron up to 2012. Since then, there has been tremendous growth in this field and numerous articles have been published after 2012. In this review, we tried to go insight and highlight the current developments in the applications of SMCR as a key and strategic step (steps) in the total synthesis of biologically active natural products accomplished and reported from 2012 till date.     

Analysis of dispersive carrier transport based on numerical solution of multiple-trapping equations

A numerical packet has been developed to solve multiple-trapping equations with an exponential trap distribution without any restrictions on the dispersion parameter, which can be both smaller and greater than unity. Attention has been focused on current transients recorded upon the near-surface, as well as bulk, excitation of the polymer in the small-signal mode. The results have been compared with published data. The program has been used for a critical review of published experimental results obtained by the time-of-flight technique.     

Transition metal-catalyzed carbon-carbon bond activation

This tutorial review deals with recent developments in the activation of C-C bonds in organic molecules that have been catalyzed by transition metal complexes. Many chemists have devised a variety of strategies for C-C bond activation and significant progress has been made in this field over the past few decades. However, there remain only a few examples of the catalytic activation of C-C bonds, in spite of the potential use in organic synthesis, and most of the previously published reviews have dwelt mainly on the stoichiometric reactions. Consequently, this review will focus mainly on the catalytic reaction of C-C bond cleavage by homogeneous transition metal catalysts. The contents include cleavage of C-C bonds in strained and unstrained molecules, and cleavage of multiple C-C bonds such as C[triple bond]C triple bonds in alkynes. Multiple bond metathesis and heterogeneous systems are beyond the scope of this review, though they are also fascinating areas of C-C bond activation. In this review, the strategies and tactics for C-C bond activation will be explained.     

Challenges and prospects of metal sulfide materials for supercapacitors

Worldwide, the research on advanced materials for energy storage devices has drawn greater attention. Numerous works on different energy storage materials has been reported and still continuing. Among the energy storage devices, electrochemical supercapacitors (ESs) are one of the most investigated topics. The globalization and increasing demand of smart and flexible devices has forced the current research to develop low-cost, high-energy density and stable ESs. In this regard, metal sulfides (MSs)–based materials have been envisioned for ESs applications owing to their unique and promising properties. Recently, several research articles have been published on MSs-based electrodes for ESs with enhanced performances. This review presents a brief survey on such recent developments towards synthesis of MSs and their use as an efficient electrode material in ESs. The challenges and future aspect involved with MSs to develop and establish it as a promising energy storage material are also discussed.     

Non‐Redox‐Metal‐Catalyzed Redox Reactions: Zinc Catalysts

The advantages of zinc catalysts, such as their low toxicity, low cost, and environmentally benignity, are encouraging organic chemists to explore their applications in organic synthesis. As a non‐redox metal, zinc catalysts have been investigated in redox reactions over the past few decades. Because of the importance of redox reactions, the interest in zinc catalysts, and the fact that no review on zinc‐catalyzed redox reactions has been published, herein, I have collected and summarized the main contributions in this area. This review is divided into two parts: reduction reactions and oxidation reactions.     

Research in the Spotlight

ELECTROPHORESIS and the Journal of Separation Science (JSS) are two complementary separation science journals published by Wiley‐VCH. For the reader to realize the full benefits from both Journals, a compilation of key research articles from JSS is reported here in this spotlight section. Similarly, JSS has created a spotlight section that compiles key research and review articles from ELECTROPHORESIS. Initially, this corner will be published bimonthly and may become a monthly publication later on. The abstracts listed below have been reduced in length to accommodate as many important papers as possible within the allotted space.     

Kinetics of adsorption of metal ions on inorganic materials: A review

It is necessary to establish the rate law of adsorbate-adsorbent interactions to understand the mechanism by which the solute accumulates on the surface of a solid and gets adsorbed to the surface. A number of theoretical models and equations are available for the purpose and the best fit of the experimental data to any of these models is interpreted as giving the appropriate kinetics for the adsorption process. There is a spate of publications during the last few years on adsorption of various metals and other contaminants on conventional and non-conventional adsorbents, and many have tried to work out the kinetics. This has resulted from the wide interest generated on using adsorption as a practical method for treating contaminated water. In this review, an attempt has been made to discuss the kinetics of adsorption of metal ions on inorganic solids on the basis of published reports. A variety of materials like clays and clay minerals, zeolites, silica gel, soil, activated alumina, inorganic polymer, inorganic oxides, fly ash, etc. have been considered as the adsorbents and cations and anions of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn as adsorbate have been covered in this review. The majority of the interactions have been divided into either pseudo first order or second order kinetics on the basis of the best fit obtained by various groups of workers, although second order kinetics has been found to be the most predominant one. The discussion under each category is carried out with respect to each type of metal ion separately. Application of models as given by the Elovich equation, intra-particle diffusion and liquid film diffusion has also been shown by many authors and these have also been reviewed. The time taken for attaining equilibrium in each case has been considered as a significant parameter and is discussed almost in all the cases. The values of the kinetic rate coefficients indicate the speed at which the metal ions adsorb on the materials and these are discussed in all available cases. The review aims to give a comprehensive picture on the studies of kinetics of adsorption during the last few years.     

Research in the Spotlight

ELECTROPHORESIS and the Journal of Separation Science (JSS) are two complementary separation science journals published by Wiley‐VCH. For the reader to realize the full benefits from both journals, a compilation of key research articles from JSS is reported here in this spotlight section. Similarly, JSS has created a spotlight section that compiles key research and review articles from ELECTROPHORESIS. Initially, this corner will be published bimonthly and may become a monthly publication later on. The abstracts listed below have been reduced in length to accommodate as many important papers as possible within the allotted space.     

Research in the Spotlight

ELECTROPHORESIS and the Journal of Separation Science (JSS) are two complementary separation science journals published by Wiley‐VCH. For the reader to realize the full benefits from both journals, a compilation of key research articles from JSS is reported here in this spotlight section. Similarly, JSS has created a spotlight section that compiles key research and review articles from ELECTROPHORESIS. Initially, this corner will be published bimonthly and may become a monthly publication later on. The abstracts listed below have been reduced in length to accommodate as many important papers as possible within the allotted space.     

Triphenylene-based discotic liquid crystals: recent advances

Since the early work of Chandrasekhar and his co-workers on hexaesters of benzene published in 1977, discotic liquid crystals (DLCs), in particular, triphenylene-based DLC materials have been investigated intensively, especially over the last decade. The first successful commercialisation of triphenylene-based DLCs has been accomplished in Fuji ‘Wide-View’ optical compensation films. DLCs represent a broad well understood class of soft matter which possess the ability to self-organise into highly anisotropic and ordered structures such as columns that function not only as organic anisotropic semiconductors, but also contribute to the development of new smart materials in the field of organic electronics for many device applications such as photovoltaic devices, light-emitting diodes, field-effect transistors, memory elements, and sensors. Over the last 35 years, more than 1000 triphenylene derivatives have been synthesised and investigated starting from structure-properties to structure-device performance relationships. The very first review by Cammidge and Bushby followed by Kumar summarised the chemistry and physical properties of triphenylene-based discotics up to 2003. In this review, progress in the research of triphenylene DLC materials since 2004 is comprehensively outlined.     

Recent developments of cyclopropene chemistry

This critical review discusses recent developments in the field of cyclopropene chemistry. Although several excellent reviews that mainly focused on the thermolysis and pyrolysis as well as metal-mediated reactions of cyclopropenes have been published, significant new developments have also been achieved in recent years. This brand new review provides an overview of the progress from 2007 to 2011 on the syntheses and transformations of cyclopropenes as well as their related mechanistic studies (238 references).     

Chemically Modified Carbon Nanotubes for Use in Electroanalysis

The discovery of carbon nanotubes has had a profound impact on many areas of science and technology, not least that of electroanalysis. The properties and applications of carbon nanotubes themselves have been well reviewed in the literature and a number of reviews with an electrochemical emphasis have been published. However, the modification of carbon nanotubes has recently been the focus of much research, primarily to improve their solubility in various solvents. Yet modified carbon nanotube electrodes also allow the electrochemist to tailor the properties of the carbon nanotubes, or the electrode surface to impart desired properties such as enhanced sensing capabilities. In this review we attempt to comprehensively cover the different chemical and electrochemical modification strategies and research carried out using modified carbon nanotubes for electroanalytical and bioanalytical applications. Furthermore we also discuss the use of modified carbon nanotubes in electrocatalysis and biocatalysis from an analytical aspect, as well as seeking to dispel some of the myths surrounding the “electrocatalytic” properties of carbon nanotubes.