On-line sample preconcentration in capillary electrophoresis, focused on the determination of proteins and peptides

Abstract

This overview highlights the possibilities of on- or in-line preconcentration procedures in combination with a CZE separation, focused on the determination of peptides and proteins. The discussed methods, including sample stacking, field-amplified injection, isotachophoresis, solid phase extraction, membrane preconcentration, electroextraction, supported liquid membranes, hollow fibers, immunoaffinity, and molecularly imprinted polymers technology preconcentration are categorized in electrophoresis-based and chromatography-based preconcentration. The chromatography-based preconcentration is subdivided in low-specificity and high-specificity methods. A number of preconcentration methods are available, however, this paper demonstrates that various compounds in different media (aqueous solutions, urine, and plasma) require different preconcentration systems. The preconcentration techniques of first choice in general seem to be solid-phase extraction and membrane preconcentration, because of their high concentration ability, multiapplicability, relative simplicity and clean-up capability. For the future, hollow fibers seem to hold a great potential as preconcentration technique, yielding high concentration factors, using simple designs. New techniques, such as hollow fibers, molecularly imprinted polymers technology and supported liquid membranes may have the potential to supersede the conventional preconcentration techniques in some cases. The larger the arsenal of preconcentration techniques becomes, the more efficiently peptides and proteins may be analyzed in the future. These techniques, in some cases, require pre-cleanup procedures, to ensure the purity of the samples to concentrate.

Recent Developments in Capillary Electrophoresis–Mass Spectrometry of Proteins and Peptides

“…The drawback, however, is that it often tends to compromise CE performance, resulting in irregular electroosmotic flow (EOF), broader peaks, and poorer resolution. 5 Waterval et al 29 developed an on-line preconcentrator using commercially available extraction disks containing poly(styrenedivinylbenzene) adsorbent particles in a matrix of inert Teflon, permitting loading of as much as 7.5 capillary volumes of a sample. They applied this later to quantitate low concentrations of gonadorelin and angiotensin II in a plasma.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] By building on these and earlier efforts, it is anticipated that the popularity of CE-MS will grow, and its advantages will be better appreciated and exploited.…”

High‐sensitive protein analysis by FESI‐CE‐MALDI‐MS

“…A variety of online sample preconcentration approaches for proteins and peptides analysis by CE have been already reported and reviewed [7,8]. The common approach is to modify the experimental parameters so as to enable the introduction of large amounts of materials in the separation capillary.…”

Experimental characterization of electrical current leakage in poly(dimethylsiloxane) microfluidic devices

“…Electroosmotic flow has been widely used to manipulate analyte samples (Li 2004). Electrophoretic and dielectrophoretic forces have also been widely used to manipulate various types of samples such as particle/cell trapping and separation (Green et al 1997;Fiedler et al 1998;Gascoyne 2002), sample pre-concentration (Lichtenberg et al 2001;Stroink et al 2001;Asbury et al 2002), and DNA/protein separation (Heller 2001;Xu et al 2002;Gao et al 2001;Doherty et al 2003).…”