On‐capillary derivatisation as an approach to enhancing sensitivity in capillary electrophoresis

Abstract

Separation technologies play an important role in revealing biological processes at various omic levels, in pharmacological and clinical research. In this context, CE is a strong candidate for analyses of samples with rapidly increasing complexity. Even though CE is well known for its many advantages in this regard, the sensitivity of CE analyses is insufficient for many applications. Accordingly, there are generally three main options for enhancing the sensitivity of CE analyses - using special detection techniques, using sample pre-concentration and derivatisation. Derivatisation is often the method of choice for many laboratories, since it is simple and provides several advantages such as small sample volume demand and the possibility of automation. Although it can be performed in different ways depending on where the reaction takes place, this article reviews one of the simplest and at the same time most useful approaches on-capillary derivatisation. Even if in many cases the use of on-capillary derivatisation alone is enough to improve the detection sensitivity, on other occasions it needs to be employed in combination with the other above-mentioned strategies. After a simple discussion of derivatisation in general, special attention is focused on the on-capillary approach and methodologies available for on-capillary reactant mixing. Its applications in various fields are also described.

High‐performance liquid chromatography evaluation of the enantiomeric purity of amino acids by means of automated precolumn derivatization with ortho‐phthalaldehyde and chiral thiols

“…The automation of the derivatization process by the autosampler of the HPLC system evades the stability issue by putting the derivatization procedure directly before the analysis, reducing the time in which the derivatives have to be stable to a minimum. This has also been reported for the analysis of OPA derivatized AAs by capillary electrophoresis . OPA reacts within a few minutes in an aqueous borate buffer (pH = 10.0) in the presence of these thiols with primary AAs to give a fluorescent isoindole product (see Figure ).…”

Improving the sensitivity in chiral capillary electrophoresis

“…In-capillary derivatization emerges as a powerful technique as it involves low reagents and sample consumption which causes minimum sample dilution. Moreover, it offers high derivatization efficiency, and allows full automation of the derivatization process which often brings better repeatability and reproducibility as reported in a recently published review article [42]. Fradi et al reported a work regarding the enantioseparation of 15 amino acids in an MEKC-UV system using (-)-1-(9-fluorenyl)ethyl chloroformate as chiral labeling reagent [35].…”

Derivatisation for separation and detection in capillary electrophoresis (2012–2015)

“…However, there were specific reviews published about the importance of derivatisation in CE for the analysis of natural products , biogenic amines in food samples , proteomics , microfluidic chip electrophoresis , peptides , herbicides and chiral amino acids . Also, a recent and comprehensive review about in‐capillary derivatisation was given by Glatz .…”