Relevance and use of capillary coatings in capillary electrophoresis–mass spectrometry

Abstract

Over the last two decades, coupled capillary electrophoresis (CE)-mass spectrometry (MS) has developed into a generally accepted technique with a wide applicability. A growing number of CE-MS applications make use of capillaries where the internal wall is modified with surface coating agents. In CE-MS, capillary coatings are used to prevent analyte adsorption and to provide appropriate conditions for CE-MS interfacing. This paper gives an overview of the various capillary coating strategies used in CE-MS. The main attention is devoted to the way coatings can contribute to a proper CE-MS operation. The foremost capillary coating methods are discussed with emphasis on their compatibility with MS detection. The role of capillary coatings in the control of the electroosmotic flow and the consequences for CE-MS coupling are treated. Subsequently, an overview of reported applications of CE-MS employing different coating principles is presented. Selected examples are given to illustrate the usefulness of the coatings and the overall applicability of the CE-MS systems. It is concluded that capillary coatings can enhance the performance and stability of CE-MS systems, yielding a highly valuable and reproducible analytical tool.

Recent advances in column coatings for capillary electrophoresis of proteins

“…One of the disadvantages of dynamic coating agents is their possible interference with the separation and/or detection systems, especially, mass spectrometry (MS). In this latter case, if the coating material enters the mass spectrometer it may cause problems such as analyte signal suppression and/or contamination of the ion source and ion optics [14]. The most frequently applied dynamic coating agents used in capillary electrophoresis analysis of proteins are summarized in Table 1.…”

“…The usual process starts with pretreatment of the capillary surface by NaOH to open up the Si-O-Si bonds and form Si-OH groups, followed by a silanization reaction with a bifunctional alkoxysilane reagent to form covalent bonds with the opportunity to attach the final or if necessary an intermediate coating material (e.g., linear polymer) [33,34]. Covalent coatings feature long-term stability and they are compatible with MS detection [14]. Recently applied frequently used permanent coatings for capillary electrophoresis separation of proteins are summarized in Table 2.…”

CE-MS in Forensic Sciences with Focus on Forensic Toxicology

“…Despite the almost universal use of physically adsorbed coatings in CZE with optical detection (since they can easily be applied, removed, or replaced), chemically bonded coatings are preferred in CE-MS, to avoid leaking of the coating material into the ion source, which may produce background noise, suppression of analyte signal, and/or contamination of the ion source and MS optics [41].…”

Analysis and role of oligosaccharides in milk

“…Labeling with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) introduces a fluorophore for the LIF detection, while simultaneously adding negative charge needed for the separation (49)(50)(51). However although good separation can be achieved using offline CE-LIF using very fast runs (around 9 minutes), both resolution and separation time have to be compromised when coupling CE to mass spectrometry (52). http://bmbreports.org BMB Reports…”