Free solution capillary electrophoresis of basic proteins in uncoated fused silica capillary tubing

Abstract

Abstract. A series of buffer systems encompassing the pH range from 3.5 to 9.0 have been developed for free solution capillary electrophoretic (CE) analysis of basic proteins in uncoated fused silica capillaries. Separations of model proteins possessing isoelectric points between 9.1-1 1 .O have been achieved with efficiencies in the range of 95,000-690,000 theoretical plates. In each case the modifier 1,3-diaminopropane is incorporated in the operating buffers at concentrations of 30-60 mM along with moderate levels of alkali metal salts to suppress protein-capillary wall interactions normally encountered with basic proteins. The combination of these buffer additives allows the analyses to be conducted at pHs below the protein isoelectric points. No special capillary pretreatment is required. The advantages of this approach to analyzing basic proteins include its simplicity, the ability to perform the analyses in the pH range where proteins are stable and the greater flexibility available in the choice of pH as a means of affecting selectivity changes.

Cellulose acetate-coated fused-silica capillaries for the separation of proteins by capillary zone electrophoresis

“…Four different approaches have been reported and involve, briefly, (i) elimination of the interaction by adjusting the pH of the buffer to such a value that the silanol groups are non-charged [1]; (ii) adjusting the pH of the buffer of such a value that the charges of the silanol groups and protein have the same sign [2,3]; (iii) dynamic modification of the surface by neutral and cationic additives in the buffer [4][5][6][7][8][9]; and (iv) chemical modification using covalent bonding of the fusedsilica surface [10][11][12][13][14][15][16][17][18].…”

Quantification of Histamine and Carcinine in Drosophila melanogaster Tissues

“…Due to EOF suppression, wall coatings or added buffer modifiers are not needed, thus simplifying the separation. 22 All analytes appeared in 800 seconds and (approximately 13.3 minutes) were well resolved from one another (Figure 1). …”

Dual‐opposite‐injection CZE: Theoretical aspects and application to organic and pharmaceutical compounds

“…Other electrolyte additives such as various salts [84], zwitterions [85,86], and organic amines [87,88] can be used to compete for the adsorption sites on the capillary wall [89].…”