On-line pH modification of carbonate eluents using an electrolytic potassium hydroxide generator for ion chromatography.
Classical gradient elution, based on the application of a gradient pump used for mixing two or more prepared eluent components in pre-determined concentrations, was replaced by a chromatography system equipped with an isocratic pump and an electrolytic KOH generator. The isocratic pump delivered a constant concentration eluent composed of pure hydrogencarbonate solution. Carbonate ions, the main component of carbonate/hydrogencarbonate-based eluents, were formed by titration of hydrogencarbonate with KOH formed on-line in the electrolytic KOH generator. By changing the concentration of electrolytically-generated KOH, the eluent composition could be changed from pure hydrogencarbonate to a carbonate/hydrogencarbonate buffer, and finally to a carbonate/hydroxide-based eluent. The described system was tested to achieve pH-based changes of retention behavior of phosphate under constant inflow eluent composition conditions.
National Institute of Chemistry, Ljubljana, Slovenia. milko.novic@ki.si
Milko
M
Novic
Yan
Y
Liu
Nebojsa
N
Avdalovic
Boris
B
Pihlar
D002254:Carbonates / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*
D002254:Carbonates; D004573:Electrolytes; D006878:Hydroxides; D017680:Potassium Compounds; C029943:potassium hydroxide