eCite Digital Repository

Mixed-mode capillary electrochromatographic separation of anionic analytes


Hilder, EF and Macka, M and Haddad, PR, Mixed-mode capillary electrochromatographic separation of anionic analytes, Analytical Communications, 36, (8) pp. 299-303. ISSN 1359-7337 (1999) [Refereed Article]

DOI: doi:10.1039/a904506f


In this work, mixed-mode capillary electrochromatography is introduced as a method for selectivity manipulation in the separation of charged analytes and is investigated for a number of analytes. This concept involves utilising a component of the eluent to permit the chromatographic and capillary electrophoresis (CE) separation mechanisms to contribute in varying proportions to the separation. This approach was first investigated using a combination of CE with reversed-phase liquid chromatography (RP-LC) for hydrophobic, charged analytes (aliphatic sulfonates), and using the concentration of organic modifier in the eluent to control the contributions of CE and RP-LC. However, the use of reversed-phase columns was found to be problematic for mobile phases with less then 50% organic modifier due to the hydrophobicity of the stationary phase causing the column bed to overheat and dry, and low electroosmotic flow (EOF) values (μ ≤ 17.8 × 10-9 m2 V-1 s-1) caused additional restrictions. In a second case, ion-exchange stationary phases were used, with the type and concentration of a competing anion in the eluent being used to control the contributions of ion chromatography (IC) and CE to the separation. Nine common inorganic anions were separated using a silica based anion-exchange column and phosphate (pH 7.20) or sulfate (pH 8.2) as eluent with direct UV detection at 214 nm and 17 inorganic and small organic anions were separated using a nitrate eluent (pH 6.80) with indirect UV detection at 214 nm. The separation selectivity was shown to be a combination of IC and CE.

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
UTAS Author:Hilder, EF (Professor Emily Hilder)
UTAS Author:Macka, M (Professor Mirek Macka)
UTAS Author:Haddad, PR (Professor Paul Haddad)
ID Code:16210
Year Published:1999
Web of Science® Times Cited:32
Deposited By:Chemistry
Deposited On:1999-08-01
Last Modified:2011-08-04

Repository Staff Only: item control page