Anion analysis using capillary ion analysis: The chemistry and performance of chromate based electrolyted

Library Number:
Krol, Jim;Mazzeo, Jeff;Benvenuti, Mark;Grover, Ed
Pittcon ''96 Chicago, IL - Presentations From Waters Corp.
Content Type:
Content Subtype:
Anion, chloride, bromide, nitrite, sulfate, nirtate, fluoride, phosphate
Abstract Capillary Ion Analysis (CIA) is a free zone capillary electrophoresis technique designed for the analysis of inorganic and organic anions and cations in aqueous matrices. It also incorporates the use of capillary electrophoresis specific data processing to account for non-symmetrical peak shapes and quantitation dependent upon migration time. For inorganic and organic anion analysis, a chromate based electrolyte is primarily used for separation and detection. In the 5 years since its commercial introduction, the data processing has evolved to differentiate capillary electrophoresis data processing from chromatography data processing. Now, the initial chromate based electrolyte has been reformulated, based upon observed performance with real samples, to optimize anion selectivity and electrolyte mobility. This electrolyte reformulation aids in analyte qualitative identification when changes in field strength and EOF are observed. This presentation will overview CIA performance of an evolved chromate electrolyte formulation that gives improved migration time stability with respect to analyte concentration, and peak shapes that allow the low ppb detection of Br, NO2, and NO3 in the presence of high concentrations of Cl and SO4. The variables of chromate concentration, osmotic flow modifier cocentration, pH, choice of buffering agents, and their effect on mobility will be discussed.