Use of High Ionic Strength Buffers for the Separation of Proteins and Peptides with Capillary Electrophoresis

Abstract

Journal of Liquid ChromatographyPublication details, including instructions for authors and subscription information: ABSTRACTThe use of high ionic strength buffers with capillary electrophoresis in untreated fused silica capillaries is demonstrated for the separation of proteins and peptides. Short, small i.d. (20-25 pm) capillaries are useful as a quick screening tool for protein analysis. Electropherograms of standard proteins run from pH 5.0 to 10.0 in 0.5 M sodium phosphate buffers suggest that at these high ionic strengths, the proteins (relative to the electrmmotic flow markers) are not always predictable functions of their PI'S. Consecutive runs of standard proteins yield excellent migration time and peak area reproducibility. Milk proteins, particularly the caseins, could be separated with the addition of 4 M urea to the buffer. Alternatively, the addition of a zwitterion to a phosphate-based buffer provide different selectivities for the protein standards. The accompanying reduction in ionic strength allows for

Rapid analysis of peptides and amino acids by CE‐ESI‐MS using chemically modified fused‐silica capillaries

“…Over the years, various strategies have been developed to diminish or eliminate interactions between analyte and FS-capillary wall, alter the EOF to achieve more rapid separation, or improve the repeatability [25]. These strategies involve the separations performed in extreme pH values [26] and in high ionic strength BGEs [27], addition of amines [28] or zwitterions [29] in BGEs, and use of coated capillaries [30][31][32][33][34][35] running buffer usually requires long analysis time due to the following two reasons. One is that low pH values would result in low EOF when using bare-FS capillary [36,37].…”

Cationic amylopectin derivatives as additives for analysis of proteins in capillary electrophoresis

“…In CE, a commonly solution to this is a use of a low pH [11] or high ionic strength buffer, sometimes with an organic modifier [12,13], and a covalent (static) [14] or dynamic coating [14][15][16][17] modification of the capillary surface. Recently, there have been many reviews on this subject [18,19].…”

Dual injection capillary electrophoresis: Foundations and applications

“…For this reason, DOI-CE is practically limited to charged analytes, and only when the EOF was not completely suppressed the determination of neutral compounds would be possible which would be moved by the low EOF together with ionic compounds with a higher and opposite sign electrophoretic mobility than the EOF. In order to allow the electrophoretic mobility of the analyte to dominate, some researchers have reduced the EOF by increasing the ionic strength of the buffer [34,35]. Brechtel et al [36] first reported the use of high-charged metal salts for this purpose.…”