The purpose of this work was the synthesis of functional particles for use in biotechnological applications such as protein purification and enzymatic conversions. The process applied combined magnetic micro-particles and aqueous micellar two-phase systems. Hydrophilic magnetic micro-particles were coupled with alkylamines of various lengths, thus improving partitioning in this switchable aqueous two-phase system. The newly introduced covalent bonds on the particle surface were verified by FTIR measurements. Different ratios of alkylamine to surface groups were tested and the surface group density was determined by titration and a novel method of considerably reduced analysis time. Finally, the chosen surface modified particles were successfully applied in an exemplary protein purification process reaching a purity of 87% and more. (C) 2015 Elsevier B.V. All rights reserved.