Preparation and evaluation of multidentate ligand-bonded silica chromatographic medium

Abstract

Iminodisuccinic acid (IDS), a green environment-friendly multidentate chelating agent, was used as a ligand to synthesize IDS-Silica stationary phase under the optimized conditions. The binding capacity of IDS on the stationary phase was measured by potentiometric titration. The chromatographic properties and metal chelating property on IDS-Silica column were investigated. Three standard protein mixtures were separated successfully with IDS-Silica column. The results showed that the IDS-Silica column displayed a typical cation exchange property. The binding characteristics of six different metal ions on IDS-Silica stationary phase were examined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results validated that the variation of binding capacities of metal ions on the stationary phase were consistent with the chelating stability order of the IDS-Silica column for metal ions. Compared with the other silica columns bonded with the three different aminocarboxyl ligands, the bonding amounts of Cu2+ on IDS-Silica column was the largest, which indicated that IDS had stronger chelating ability for metal ions. This characteristic lays the foundation for IDS as a good chromatographic packing used in the field of immobilized metal affinity chromatography (IMAC), thus probably provides an effective solution to reduce the leaking problem of metal ion from IMAC column during protein elution with one competitive agent.