eCite Digital Repository

High-Resolution Computer Simulations of Stacking of Weak Bases Using a Transient pH Boundary in Capillary Electrophoresis. 1. Concept and Impact of Sample Ionic Strength

Citation

Breadmore, MC and Mosher, RA and Thormann, W, High-Resolution Computer Simulations of Stacking of Weak Bases Using a Transient pH Boundary in Capillary Electrophoresis. 1. Concept and Impact of Sample Ionic Strength, Analytical Chemistry, 78, (2) pp. 538-546. ISSN 0003-2700 (2006) [Refereed Article]

DOI: doi:10.1021/ac051420f

Abstract

The dynamics of focusing weak bases using a transient pH boundary was examined via high-resolution computer simulation software. Emphasis was placed on the mechanism and impact that the presence of salt, namely, NaCl, has on the ability to focus weak bases. A series of weak bases with mobilities ranging from 5 × 10 -9 to 30 × 10 -9 m 2/ V·s and pK a values between 3.0 and 7.5 were examined using a combination of 65.6 mM formic acid, pH 2.85, for the separation electrolyte, and 65.6 mM formic acid, pH 8.60, for the sample matrix. Simulation data show that it is possible to focus weak bases with a pK a value similar to that of the separation electrolyte, but it is restricted to weak bases having an electrophoretic mobility of 20 × 10 -9 m 2/V·s or quicker. This mobility range can be extended by the addition of NaCl, with 50 mM NaCl allowing stacking of weak bases down to a mobility of 15 × 10 -9 m 2/V·s and 100 mM extending the range to 10 × 10 -9 m 2/V·s. The addition of NaCl does not adversely influence focusing of more mobile bases, but does prolong the existence of the transient pH boundary. This allows analytes to migrate extensively through the capillary as a single focused band around the transient pH boundary until the boundary is dissipated. This reduces the length of capillary that is available for separation and, in extreme cases, causes multiple analytes to be detected as a single highly efficient peak. © 2006 American Chemical Society.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Analytical Chemistry
Research Field:Separation Science
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Breadmore, MC (Professor Michael Breadmore)
ID Code:43013
Year Published:2006
Web of Science® Times Cited:38
Deposited By:Chemistry
Deposited On:2006-08-01
Last Modified:2007-04-02
Downloads:0

Repository Staff Only: item control page