Development of dihydrazide-activated silica supports for high-performance affinity chromatography

A method of preparing dihydrazide-activated silica was developed for use in high-performance affinity chromatography (HPAC). This support was made by oxidizing diol-bonded silica and reacting it with oxalic or adipic dihydrazide. The steps involved in this synthesis were studied and confirmed by FTIR. Items considered in optimizing the preparation of the support included the amount of dihydrazide added and the reaction time or pH used. Control of dihydrazide bifunctional attachment was obtained by varying the extent of diol-bonded silica oxidation. This support was successfully used in the immobilization of oxidized antibodies, horse radish peroxidase (a glycoenzyme) and transfer RNA. In each case, data indicated that immobilization was through site specific coupling rather than non-specific adsorption. Dihydrazide-activated silica was found to be stable for 2-6 weeks after preparation when stored at 5 to 25 degrees C. The linkage between oxidized biomolecules and this support was stable for at least one month in the presence of various solvents commonly used in HPAC.