Novel methods are described to synthesize chromatography media. The methods describe a crosslinking procedure utilizing the catalytic effect of MnO(OH)2 in obtaining a very rigid matrix. The mechanism of crosslinking is likely of free-radical type. This is also suggested by the concurrent functionalization steps which are known to be of free-mechanism and are greatly enhanced by MnO(OH)2. The methods are simple and efficient as crosslinking and functionalization of the matrix takes place in the same step. High protein binding capacities are obtained along with an increased efficiency of the matrix. One particularly preferred process according to the present invention comprises: (1) reacting a polymeric carbohydrate matrix with an activating reagent which contains a halogen atom or epoxide and a double bond under alkaline conditions to generate an activated matrix; (2) reacting the activated matrix having double bonds inserted with a reagent or reagents produding MnO(OH)2; and (3) activating the double bond in the presence of MnO(OH)2 to crosslink the matrix and simultaneously derivatize the matrix with a halohydrin, carboxyl or sulfonate group.