Selectivity behaviour of a bonded phosphonate--carboxylate polymeric ion exchanger for metal cations with varying eluent compositions.
The chromatographic behaviour of a commercially available ion-exchange stationary phase (the Dionex IonPac CS12A column) is described for a wide range of transition and heavy metal ions with nitric acid eluents containing chloride and nitrate potassium salts. The separation selectivity was found to arise from simultaneous ion-exchange interactions and chelation with the attached carboxylic and phosphonic acid groups. These interactions were investigated by altering the ionic strength and pH of the eluent and also the column temperature. Strong affinity of the stationary phase towards heavy metal ions, in particular bismuth and the uranyl ion was observed at low pH under chelating ion-exchange conditions, with high efficiency separations of other ions including cadmium and lead being possible with short analysis times (approximately 5-15 min). Examples are given of separations obtained using 4-(2-pyridylazo)resorcinol or Arsenazo III as the post-column chromogenic reagents, demonstrating the potential versatility and utility of this stationary phase for heavy metal ion analysis.
Shaw
Matthew J
MJ
Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, GPO Box 252-75, Hobart 7001, Tasmania, Australia. matthew.shaw@utas.edu.au
Nesterenko
Pavel N
PN
Dicinoski
Greg W
GW
Haddad
Paul R
PR
D002264:Carboxylic Acids; D002412:Cations; D002712:Chlorides; D002852:Chromatography, Ion Exchange / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007475:Ion Exchange Resins; D008670:Metals / Q000032:analysis*; D063065:Organophosphonates; D009994:Osmolar Concentration; D011108:Polymers; D013696:Temperature
D002264:Carboxylic Acids; D002412:Cations; D002712:Chlorides; D007202:Indicators and Reagents; D007475:Ion Exchange Resins; D008670:Metals; D063065:Organophosphonates; D011108:Polymers