Congo red was immobilised onto monosize and non-porous poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [p(HEMA-co-MMA)] copolymer microparticles (4.0 mu m in diameter). Then Fe(III) ions were complexed by chelation with the immobilised congo red molecules. Different amounts of Fe(III) ions were loaded on the dye-derived microparticles by changing the concentration of Fe(III) ions and pH of the reaction medium. Congo red-derived and Fe(III)-complexed microparticles were used in the adsorption of glucose oxidase, catalase, lysozyme and bovine serum albumin. The maximum adsorption capacities of these microparticles were determined by changing pH and the concentration of the proteins in the adsorption medium. Their adsorption behavior can be described at least approximately with the Langmuir equation. Glucose oxidase, catalase, lysozyme and bovine serum albumin adsorption capacities of the Fe(III) complexed microparticles (165.1, 135.2, 67.6 and 44.5 mg g(-1)) were higher than those of the congo red-immobilised microparticles (125.9, 94.2, 35.8 and 21.2 mg g(-1), respectively). The non-specific adsorption of the proteins on the p(HEMA-co-MMA) microparticles was negligible. The resulting dye- and metal-chelate affinity microparticles have excellent reusability and long term storage stability. (C) 2000 Elsevier Science B.V. All rights reserved.