High-performance chelation ion chromatography of transition and heavy metal ions on polystyrene–divinylbenzene resin dynamically modified with 4-chlorodipicolinic acid

A neutral polystyrene–divinylbenzene column, combined with 4-chlorodipicolinic acid present in the mobile phase, has been developed as a chromatographic system for the high efficiency isocratic separation of transition and heavy metal ions. Retention arises from the formation of a stable dynamically coated chelating stationary phase, the capacity of which is dependent upon both the pH and ligand concentration in the eluent. The results obtained illustrate the increased loading and selectivity of this chlorinated chelating molecule in comparison with unsubstituted dipicolinic acid, exemplified by the separation of 7 metals in under 8 min. The column also displayed a strong affinity for CdII and an unusual retention for NiII, which showed a good symmetrical peak shape.