François Couderc

This paper describes the most important articles that have been published on amino acid analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078–3083), Prata et al. (Electrophoresis 2001, 22, 4129–4138) and Poinsot et al. (Electrophoresis 2003, 24, 4047–4062; Electrophoresis 2006, 27, 176–194; Electrophoresis 2008, 29, 207–223; Electrophoresis 2010, 31, 105–121). We present new developments in amino acid analysis with CE, which are reported describing the use of lasers or light emitting diodes for fluorescence detection, conductimetry electrochemiluminescence detectors, mass spectrometry applications, and lab‐on‐a‐chip applications using CE. In addition, we describe articles concerning clinical studies and neurochemical applications of these techniques.

This article describes the most important articles that have been published on amino acid analysis using CE during the period from June 2007 to May 2009. It follows the format of the previous articles of Smith [Electrophoresis 1999, 20, 3078–3083], Prata et al. [Electrophoresis 2001, 22, 4129–4138] and Poinsot et al. [Electrophoresis 2003, 24, 4047–4062; Electrophoresis 2006, 27, 176–194; Electrophoresis 2008, 29, 207–223]. For several years we have presented the new developments in amino acid analysis with CE which describe the use of laser emitting diodes for LIF as well as via MS. In addition, we describe articles concerning clinical studies and neuroclinical applications.

An LIF detector was integrated into a CE system which uses a ball lens to focus the laser beam on the CE capillary. The detector employs an ellipsoid that is glued on the capillary window, to permit the collection of the fluorescence in the capillary. This ‘trapped’ fluorescence stays in the capillary because the angle of the silica/air interface is greater than the critical angle. The performance of this new detector setup is found to be identical to the collinear setup using the same ball lens. An application to the analysis of FITC‐labeled IgG was optimized using a 14 cm effective length capillary. The LOD of an FITC‐labeled IgG2 at an excitation wavelength of 488 nm was 150 pg/mL, which was 10 times better than the LOD recorded with slab gel silver staining. Using a tetramethylrhodamine (TAMRA)‐labeled IgG2 and a 532 nm excitation wavelength the LOD is 50 pg/mL. The electropherograms of four different commercial FITC conjugates of IgG were studied. The presence of aggregates was observed in two samples while close kinetics of reduction was observed between free aggregates and high aggregates concentration samples. The integrated LIF detector provides an extremely powerful and convenient tool for antibody analysis and should be useful for therapeutic MAb control in pharmaceutical facilities.

This paper describes a number of articles that have been published on amino acid (AA) analysis using CE during the period from June 2005 to May 2007. This review article follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078–3083), Prata et al.. (Electrophoresis 2001, 22, 4129–4138), and Poinsot et al.. (Electrophoresis 2003, 24, 4047–4062 and Electrophoresis 2006, 27, 176–194). Several new developments in AA analysis with CE are reported describing the use of laser‐emitting diodes for LIF, MS, and chips. In addition, we describe articles concerning clinical studies and neuroclinical applications.

This paper reviews analytical methods, instrumental developments and applications for derivatization of primary amines with naphthalene‐2,3‐dicarboxaldehyde using fluorescence and chemiluminescence detection with capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). The use of lasers as well as lamps as the excitation source for fluorescence detection is discussed. The detection limit observed with naphthalene‐2,3‐dicarboxaldehyde derivatization is often lower and better than those obtained with other analytical separations and other fluorescent dyes. In addition, this paper describes the crucial points that influence the stability of NDA primary amine derivatives, and summarize the separation, derivatization and migration conditions of the different techniques, with their advantages and drawbacks. Copyright © 2007 John Wiley & Sons, Ltd.

Naphthalene‐2,3‐dicarboxyaldehyde (NDA) is commonly used for detection of primary amines in conjunction with their separation with HPLC and CE. The fluorescence of the derivatives can be measured by a conventional fluorometer or via LIF. NDA is a reactive dye, which can replace o‐phthaldehyde (OPA) and provides for derivatives which are considerably more stable than OPA derivatives. In addition, NDA can be used to derivatize primary amines at concentrations as low as 100 pM. In this work, HPLC/fluorescence and MEKC/LIF experiments were performed to separate/detect six neuroactive compounds, the amino acids, Gly, Glu, Asp, γ‐aminobutyric acid (GABA) and the catecholamines, dopamine and noradrenaline. The two methods were compared in terms of performance of separation. The amino acids can be separated in HPLC in less than 30 min and an identical separation is obtained in CE using MEKC and lithium salts with greater resolution (the number of theoretical plates was approximately 5000 for HPLC and 200 000 for MEKC). The lowest detected concentration was in the range of 0.1 nM for CE/LIF. The presence of a high salt concentration does not affect the separation of the samples. Examples of the analysis of microdialysate samples as well as amino acids in Ringer's solution are presented.

This paper describes a number of articles that have been published on amino acid analysis using CE during the period from June 2003 to May 2005. This review article follows the previous ones of Smith (Electrophoresis 1999, 20, 3078–3083), Prata et al.. (Electrophoresis 2001, 22, 4129–4138), and Poinsot et al.. (Electrophoresis 2003, 24, 4047–4062). Several new developments in amino acid analysis with CE are reported concerning UV detection, LIF, MS, and NMR. In addition, we describe articles concerning clinical and pharmaceutical studies, neuroclinical applications, and agricultural and food analysis.

Over the past few years, a large number of studies have been prepared that describe the analysis of peptides and proteins using capillary electrophoresis (CE) and laser‐induced fluorescence (LIF). These studies have focused on two general goals: (i) development of automatic, selective and quick separation and detection of mixtures of peptides or proteins; (ii) generation of new methods of quantitation for very low concentrations (nm and subnanomolar) of peptides. These two goals are attained with the use of covalent labelling reactions using a variety of dyes that can be readily excited by the radiation from a commonly available laser or via the use of noncovalent labelling (immunoassay using a labelled antibody or antigen or noncovalent dye interactions). In this review article, we summarize the works which were performed for protein and peptide analysis via CE‐LIF.

Oxidative stress is present in cardiovascular diseases and hyperhomocysteinemia, an independant risk factor for these diseases. It may play a role by inducing production of oxygen free radicals. Reduced glutathione is the most abundant intracellular low‐molecular‐weight thiol and plays an essential role in protecting cells from toxic species. The thiol‐containing compounds which are the most often considered in biological analysis, are homocysteine (Hcy), cysteine (Cys), glutathione (GSH), cysteinyl‐glycine (Cys‐Gly), γ‐glutamyl‐cysteine (γGlu‐Cys), and their derivatives. These aminothiols are present in body fluids or cells, associated with proteins or occur free (reduced and oxidized). These free forms may play a role in the pathogenesis of disease. Because Hcy (with Cys) exhibits pro‐oxidative properties and GSH (with Cys‐Gly) antioxidative properties, and because there is extensive interconversion between these metabolites, their simultaneous analysis in biological samples is necessary to examine their role in human disease. Capillary electrophoresis (CE) seems to be a solution to reach this goal. No extensive review reports the analysis of aminothiols using CE. This review describes the different CE approaches which have been used to separate and assay aminothiols, and the different obtained datas.

Amino acids are studied extensively using capillary electrophoresis. In a previous article, we reviewed applications reported in the period 1999 – early 2001 (Prata, C., Bonnafous, P., Fraysse, N., Treilhou, M., Poinsot, V., Couderc, F., Electrophoresis 2001, 22, 4129–4138). In this article we follow on with this review for the period end of 2001 – beginning of 2003. We will report the developments of detection methods, separations of enantiomers, the new medical applications, and amino acids in food and plants. This review shows that CE is more and more important for the amino acid analysis.