An apparatus for reaction chromatography comprising: a chromatography column, the column having a fluid outlet for an eluate flow, wherein the fluid outlet is configured with two or more fluid ports, the two or more fluid ports comprising one or more reactant ports, wherein each reactant port is for connecting a reactant flow into the eluate flow to react with the eluate flow, and one or more product ports for receiving the reacted eluate flow; one or more reactant sources in fluid communication with the one or more reactant ports to provide the reactant flow; and one or more processing units in fluid communication with the one or more product ports to process the reacted eluate flow.