Chromatographic properties of the ion-exclusion column IonPac ICE-AS6 and application in environmental analysis. Part I: Chromatographic properties.
The chromatographic performance of the Dionex IonPac ICE-AS6 ion exclusion column is investigated. Therefore, capacity factors, efficiency, peak symmetry, resolution, and selectivity are determined for various mono- and polyfunctional aliphatic carboxylic acids under selected chromatographic conditions. Except for the stronger acids (pKa1 < 3.75), the highest chromatographic efficiency is achieved at a column temperature of 40 or 50 degrees C, and peak shape is found to be optimal at approximately 60 degrees C. The separation of the stronger acids is favored by an eluent pH below 3.0 and column temperatures below 40 degrees C. The maximal effective plate numbers range between 126 (tartronic acid) and 6380 (4-oxovaleric acid). Hydroxy-substituted acids are less retained and less influenced by temperature changes than the unsubstituted compounds. It is estimated that size exclusion effects take part in the separation of aldonic acids. The addition of 1% isopropanol to the acidic eluent increases the chromatographic efficiency generally, whereas higher concentrations reduce the retention of several acids drastically.
Fischer
K
K
GSF-National Research Center for Environment and Health, Institute of Ecological Chemistry, Neuherberg, Germany. fischerk@uni-trier.de
Kotalik
J
J
Kettrup
A
A
D000143:Acids / Q000032:analysis; D002850:Chromatography, Gel; D004785:Environmental Pollutants / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D012015:Reference Standards; D013696:Temperature
D000143:Acids; D004785:Environmental Pollutants; D007202:Indicators and Reagents