N,N,N′,N′‐Tetramethyl‐1,3‐butanediamine as effective running electrolyte additive for efficient electrophoretic separation of basic proteins in bare fused‐silica capillaries

Abstract

The effect of N,N,N',N'-tetramethyl-1,3-butanediamine (TMBD) in the running electrolyte on the electroosmotic flow and the migration behavior of four standard basic proteins in bare fused-silica capillaries was examined at pH 4.0, 5.5, and 6.5. Depending on the electrolyte pH and additive concentration the electroosmotic flow was either cathodic or anodic. A similar Langmuirian-type dependence of the electroosmotic flow on the concentration of TMBD in the running electrolyte was found at the three experimented pH values, which may be indicative of the specific adsorption of the additive in the immobilized region of the electric double layer at the interface between the capillary wall and the electrolyte solution. Electrophoretic separations of the four standard basic proteins performed at the three above pH values, showed well-resolved, efficient and symmetric peaks, demonstrating the utility of this additive for protein electrophoresis in bare fused-silica capillaries. The variations in separation efficiency, peak capacity, resolution and reproducibility of migration times as a function of the additive concentration at pH 6.5 were also examined.

Microchannel wall coatings for protein separations by capillary and chip electrophoresis

“…Tertiary amines such as triethanolamine [93], triethylamine or N-ethyldiethanolamine [91], diamines such as N,N,N',N'-tetramethyl-1,3-butanediamine (TMBD) [92], putrescine, cadaverine [93], and a, o-bis-quaternary ammonium alkanes [94], primary amines, such as ethylamine [93], and oligoamines such as tetraethylenepentamine (TEPA) and spermine [93] have all been employed as buffer additives (see Table 2). Alkylamines are believed to interact strongly with silanol groups at the capillary surface, modifying the charge at the surface.…”

A very thin coating for capillary zone electrophoresis of proteins based on a tri(ethylene glycol)‐terminated alkyltrichlorosilane

“…Alkylamines are believed to interact strongly with silanol groups at the capillary surface, modifying the charge at the surface, and potentially reversing EOF [46][47][48][49][50]. Various types of surfactants, including cationic [40,51,52], anionic, zwitterionic [53][54][55], nonionic [54], and fluorosurfactants [56] have been used as buffer additives to suppress adsorption and tune EOF, and can allow separation of both cationic and anionic proteins in a single run.…”

Separation of basic proteins and peptides by capillary electrophoresis using a cationic surfactant

“…These coatings, however, show a limited life-time; the coating process usually consists of multistep reactions, which are quite laborious and time-consuming. [29], tertiary alkyldiamines [30,3 11,and CTAB [23,32,33]. Many of these additives reverse the direction of the electroosmotic flow.…”