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Factors influencing the choice of buffer in background electrolytes for indirect detection of fast anions by capillary electrophoresis

Citation

Doble, PA and Macka, M and Haddad, PR, Factors influencing the choice of buffer in background electrolytes for indirect detection of fast anions by capillary electrophoresis, Electrophoresis, 19, (12) pp. 2257-2261. ISSN 0173-0835 (1998) [Refereed Article]

DOI: doi:10.1002/elps.1150191235

Abstract

The suitability of relatively slow (low absolute value of mobility) coanionic buffers in background electrolytes (BGEs) for indirect photometric detection of artions by capillary electrophoresis was investigated. As a model system, 2-(cyclohexylamino)ethanesulfonic acid (CHES) was used to buffer the indirect detection electrolyte of sodium chromate. CHES (pK(a) 9.55) is a zwitterionic molecule carrying a net negative charge depending on the pH (effective charge -0.5 at pH = pK(a)), within its useful pH buffering range CHES acted as a competing probe coanion. System peaks were induced which had deleterious effects on the detection sensitivity of slow to medium mobility anions. The mobility of the system peak was determined by the effective mobility of CHES, both of which increased with increasing pH. The peaks of analytes that migrated near or on the system peak were distorted and lost all quantitative properties. Analytes that migrated after the system peak either were not detected or reversed their responses. Analytes that migrated well before the system peak were unaffected. Consequently, the suitability of slow coanionic buffers is limited either to (i) fast anions or, (ii) a pH range much below the PK(a), where the buffering capacity is not optimal.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Analytical Chemistry
Research Field:Instrumental Methods (excl. Immunological and Bioassay Methods)
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Doble, PA (Mr Philip Andrew Doble)
Author:Macka, M (Professor Mirek Macka)
Author:Haddad, PR (Professor Paul Haddad)
ID Code:14156
Year Published:1998
Web of Science® Times Cited:13
Deposited By:Chemistry
Deposited On:1998-08-01
Last Modified:2011-08-09
Downloads:0

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