Advances in the development and applications of organic-silica hybrid monoliths.

This review will concentrate on recent progress (since 2013) toward preparation of organic-silica hybrid monoliths and their latest applications as extraction and separation media largely focusing on capillary liquid chromatography and capillary electrochromatography. Main emphasis will be given to advancement of approaches relying on the sol-gel chemistry of tetra- and tri-alkoxysilanes, sol-gel chemistry of alkoxysilanes and free-radical copolymerization with organic monomers, and free radical and ring-opening copolymerization of polyhedral oligomeric silsesquioxanes with organic monomers. Hybrid molecularly-imprinted polymer monoliths and hybrid monoliths made with non-silica-based precursors or in combination with metal alkoxides will be included as well.

Enantioseparations in open-tubular capillary electrochromatography: Recent advances and applications.

This review highlights recent advances and applications in open-tubular capillary electrochromatography (OT-CEC) for enantioseparations during the last decade. Although extensive research has been conducted in the area of separations by use of CEC, and a big number of reviews have been published, there is not a review on exclusively the use of chiral stationary phases (CSPs) in OT-CEC for enantioseparations. Therefore, in this review, the design and synthesis of different CSPs are presented, and their potential applications in OT-CEC for enantioseparations are discussed. The different approaches to CSP development include chiral nanomaterials, porous layers, molecular imprinting, sol-gel technique, polyelectrolyte multilayer coating, polymeric coating and others.

Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed.

Recent advances in preparation and application of hybrid organic-silica monolithic capillary columns.

Hybrid organic-silica monolithic columns, regarded as a second generation of silica-based monoliths, have received much interest due to their unique properties over the pure silica-based monoliths. This review mainly focuses on development in the fields of preparation of hybrid monolithic columns in a capillary and their application for CEC and capillary liquid chromatography separation, as well as for sample pretreatment of solid-phase microextraction and immobilized enzyme reactor since July 2010. The preparation approaches are comprehensively summarized with three routes: (i) general sol-gel process using trialkoxysilanes and tetraalkoxysilanes as coprecursors; (ii) "one-pot" process of alkoxysilanes and organic monomers concomitantly proceeding sol-gel chemistry and free radical polymerization; and (iii) other polymerization approaches of organic monomers containing silanes. The modification of hybrid monoliths containing reactive groups to acquire the desired surface functionality is also described.

Enantioselective capillary electrochromatography: recent developments and new trends.

Since its development in the early 1970s, CEC has been studied quite extensively, but unfortunately its use is still mostly located at an academic level. Reasons for this are the limited availability of commercially available stationary phases (SPs) and columns, along with some practical limitations, such as column fragility, lack of column robustness and reproducibility. Nevertheless, CEC maintains a place among the separation techniques, probably because of its unique feature to combine two separation principles. Also in the field of chiral separations, CEC is often used as a separation technique and already showed its potential for this kind of analyses. This overview will focus on the recent applications, i.e. between 2006 and 2010, in enantioselective analysis by means of CEC. For the selected applications, the used SPs (chiral selectors) and their potential for future method development or screening purposes will be evaluated and critically discussed.

Trends in nonpolar polymer-based monolithic columns for reversed-phase capillary electrochromatography.

This review article is concerned with describing the various strategies that have been introduced for the preparation of nonpolar polymer-based monolithic columns for RP-CEC. First, the various traditional ways of generating the EOF that involved the introduction of fixed charges on the surface of the monoliths are reviewed. This is followed by a description of the development of neutral monoliths as the most promising monoliths for the separation of a wide range of neutral and charged species at a relatively moderate to strong EOF in the absence of electrostatic attraction or repulsion.

[Microchip electrochromatography: the latest developments and applications].

This review summarizes recent developments and applications of microchip electrochromatography (microCEC) mainly in the past five years between 2005 and 2009 with a focus on column technologies. In addition, some new improvements in the chip design and fabrication, sample preconcentration, electroosmotic flow control as well as mechanisms that govern electrochromatographic separation are described and reviewed. The features and limitations of several practical aspects of their applications are highlighted.

[Recent advances in column for hydrophilic interaction capillary electrochromatography].

Hydrophilic interaction capillary electrochromatography (HI-CEC) is one of the hot spots in micro-separation technique, and the research of HI-CEC stationary phase has attracted much attention. In this paper, the research progress of open-tubular column, the particle-packed column and the monolithic column for HI-CEC are reviewed, especially for the recent progress of the monolithic CEC.

CEC: selected developments that caught my eye since the year 2000.

During the last decade, a number of new developments have emerged in the field of CEC. This paper focuses only on monolithic columns prepared from synthetic polymers. Monolithic columns have become a well-established format of stationary phases for CEC immediately after their inception in the mid-1990s. They are readily prepared in situ from liquid precursors. Also, the control over both porous properties and surface chemistries is easy to achieve. These advantages make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. Since the number of papers concerned with just this single topic of polymer-based monolithic CEC columns is large, this overview describes only those approaches this author found interesting.

Recent advances in the analysis of antibiotics by CE and CEC.

This article reviews the most recent developments concerning the determination of antibiotics by CE and CEC. The most employed CE separation modes were CZE and MEKC although microemulsion electrokinetic capillary chromatoghraphy was also employed. For the first time, CE was coupled to MS that was applied as a specific and confirmatory detection technique for the analysis of antibiotics. The analytical characteristics of the developed methodologies as well as the different applications reported in the literature on this subject from June 2005 until May 2007 are included in this article. To give the most relevant information on this topic, the experimental conditions employed to achieve the analysis of antibiotics by CE and CEC are provided together with the main applications performed in the pharmaceutical, agrochemical, biological, food, and environmental fields, emphacizing sample preparation requirements needed in each case.

Recent advances in CE and CEC of pollutants.

Recent advances in CE and CEC separation, detection and sample preparation/preconcentration methodologies, for the determination of a variety of compounds having current or potential environmental relevance, have been overviewed. The reviewed literature has illustrated the wide range of CE applications available, indicating a continuing interest in CE and CEC in the environmental field. New developments in chip-based CE systems are also discussed.

Recent accomplishments in the field of enantiomer separation by CEC.

The present review intends to summarize recent developments in the field of enantioselective separations and analysis by CEC. It covers studies published in English language in common peer-reviewed journals within the period between 2003 and 2006. Both, methods making use of chiral mobile phase additives as well as chiral stationary phases for electrochromatographic enantiomer separations, are reviewed. Achievements that have been made on the various column technologies, such as open-tubular, particle-packed, inorganic, organic and particle-fixed (hybrid-type) monolithic as well as molecularly imprinted polymer phases, are discussed.

Recent advances in sheathless interfacing of capillary electrophoresis and electrospray ionization mass spectrometry.

On line sheathless capillary electrophoresis (CE)-electrospray ionization (ESI) mass spectrometry is developing as a powerful method in bioanalytics as it provides high resolution, sensitivity, relatively short analysis times, and amenability to a wide class of compounds. However, unlike the popular nano liquid chromatography (nano LC) or sheath-flow CE/ESI-MS, the sheathless coupling lacks standardized designs and protocols. For this reason, sheathless CE/ESI is a subject of conceptual and technical upgrading more than any other liquid-based separation method hyphenated to MS. Here, recent innovations in sheathless CE/ESI-MS interfacing are gathered in a survey covering the 2005/2006 period. In the first part of the review, the current concepts and methods for in-laboratory production of sturdy designs based on either conductive emitters or electrodeless interfaces are described. The second part is dedicated to microchip CE platforms with externally connected emitters for sheathless coupling to ESI-MS and advanced microfluidic devices integrating CE and sheathless electrospray in a single chip substrate. The advantages, limitations and feasibility for certain applications of all these systems as well as the perspectives for their performance improvement are concurrently assessed.