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Previous models for the retention behaviour of carboxylic acids in ion-exclusion chromatography are applicable only when the degree of ionisation of the analyte is constant over the entire chromatographic peak. When solutions of sulfuric acid are used as eluents, this condition applies only when the eluent concentration is considerably higher than that of the analyte. Since it is common for dilute solutions of sulfuric acid to be used as eluents, a retention model which accounts for unbuffered eluents has been developed. This model also considers the effects on retention of hydrophobic adsorption of the undissociated and dissociated forms of the analyte onto the stationary phase substrate, as well as the effects of organic solvents added to the eluent. The derivation of this model is presented and it has been evaluated using a comprehensive set of retention data obtained using three different sulfonated stationary phases over a range of eluent conditions. The adsorption coefficients calculated from the model are in accordance with expected trends and showed that both the undissociated and dissociated forms of the analyte acids were retained by hydrophobic adsorption effects, although this adsorption was much stronger for the undissociated analytes.

Item Type:	Refereed Article
Keywords:	Carboxylic acids; Retention models; Mathematical modelling; Ion-exclusion chromatography; Adsorption
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:	Ng, KL (Miss Kai Ng)
Author:	Glod, B (Dr Bronislaw Glod)
Author:	Dicinoski, GW (Associate Professor Gregory Dicinoski)
Author:	Haddad, PR (Professor Paul Haddad)
ID Code:	22187
Year Published:	2001
Web of Science® Times Cited:	16
Deposited By:	Chemistry
Deposited On:	2001-08-01
Last Modified:	2010-02-08
Downloads:	0