A novel method of activation of cross-linked agaroses with 1,1'-carbonyldiimidazole which gives a matrix for affinity chromatography devoid of additional charged groups.

1,1'-Carbonyldiimidazole, a carbonylating reagent, has been shown to be suitable for the activation of cross-linked agaroses for affinity chromatography. The activated matrix (an imidazolyl carbamate) is relatively stable to hydrolysis but smoothly reacts with N-nucleophiles such as those present in either affinity chromatography ligands or leashes, e.g. ethylenediamine or 6-aminohexanoic acid. If butylamine was attached via the 1,1'-carbonyldiimidazole method, the resulting product was devoid of charged groups and thus had the same titration curve as agarose. The suitability of this new matrix for affinity chromatography was demonstrated by the successful purification of trypsin by several different systems.