Revealing the potential of capillary electrophoresis/mass spectrometry: the tipping point

Abstract

The hyphenation of capillary electrophoresis and mass spectrometry (CE/MS) remains a minor technique compared with liquid chromatography/mass spectrometry (LC/MS), which represents nowadays the standard instrumentation, regardless of its introduction thirty years ago. However, from a theoretical point of view, CE coupling should be quite favorable especially with electrospray ionization mass spectrometry (ESI-MS). At the time, the sensitivity provided by CE/MS was often limited, due to hyphenation requirements, which at some point appeared to disqualify CE/MS from benefiting from the performance gain driving the evolution of MS instruments. However, this context has been significantly modified in a matter of a few years. The development of innovative CE/MS interfacing systems has enabled an important improvement regarding sensitivity and reinforced robustness in order to provide an instrumentation accessible to the largest scientific community. Because of the unique selectivity delivered by the electrophoretic separation, CE/MS has proved to be particularly relevant for the analysis of biological molecules. The conjunction of these aspects is motivating the interest in CE/MS analysis and shows that CE/MS is mature enough to enrich the toolbox of analytical techniques for the analysis of complex biological samples. Here we discuss the characteristics of the major types of high-sensitivity CE/ESI-MS instrumentation and emphasize the late evolution and future positioning of CE/MS analysis for the characterization of biological molecules like peptides and proteins, through some pertinent applications.

Recent developments in capillary and microchip electroseparations of peptides (2019–mid 2021)

“…Thanks to its both universality and selectivity as well as high sensitivity and rich information content, MS has become the most powerful detection mode for CE, CEC, and other separation methods. The recent developments in the area of MS detection in CE methods have been described in several reviews dealing with CE-MS in general [165][166][167][168] and with its application to peptide, protein, peptidomic, metabolomic, and proteomic analyses especially [9,10,15,16,43,[169][170][171]. Importance of MS as analytical and structure elucidation method has significantly increased in the last years due to its key role in the proteomics, peptidomics, metabolomics, and other omics technologies [172].…”

Trends in Sample Preparation for Proteome Analysis

“…Historically, it has been less robust than nanoLC but recently this has begun to change. Specifically, the introduction of CE-ESI interfaces that do not lead to an excessive peptide dilution have made [44]. Several reports describe various proteomic pipelines coupling CE to MS. An ultrasensitive electrokinetically pumped nanospray ionization source coupled with CE was able to identify 283 proteins from 80 ng of MCF7 breast cancer cells.…”

Structural identification and absolute quantification of monoclonal antibodies in suspected counterfeits using capillary electrophoresis and liquid chromatography-tandem mass spectrometry

“…Especially, the implementation of capillary zone electrophoresis (CZE) [ 18 ], capillary isoelectric chromatofocusing (cIEF) [ 19 ], or micellar electrokinetic chromatography (MEKC) appeared relevant for mAbs characterization [ 20 ]. Indeed, the electrokinetically driven separation of CE showed to be suitable for the analysis of polar and charged macromolecules like mAbs in addition to provide relevant specificities [ 21 ]. Mass spectrometry (MS) has also quickly gained a key role in the characterization of therapeutic proteins [ 22 , 23 ].…”