Provided is an improved method for preparation of insoluble molecular imprinted polymers (MIPs), the method comprising: a) providing soluble or semi-soluble MIPs that 1) substantially all bind template agents and 2) have sizes which enable their separation in a chromatographic step utilizing packed bed chromatography, b) cross-linking the template agent binding soluble MIPs provided in step a so as to obtain insoluble template agent binding MIPs, and c) optionally isolating, concentrating or purifying the MIPs obtained by the cross-linking in step b. In an interesting embodiment, step a includes an affinity purification procedure, which ensures that the MIPs provided in step a are indeed all binders of the template.
