The aim of this work was to develop a trypsin-based micro-immobilized enzyme reactor prepared on a monolithic ethylenediamine BIA Separations CIM (convective interaction media) minidisk. The micro-immobilized enzyme reactor (IMER) was integrated in a liquid chromatography system hyphenated to electrospray ionization tandem mass spectrometry to carry out on-line protein digestion and identification. The performance of this IMER was compared with that obtained using a previously developed bioreactor prepared on a conventional CIM ethylenediamine disk and with that of the commercially available Poroszyme immobilized trypsin cartridge. In this work, we showed how different proteins were identified with good recoveries using a digestion time of 10min only.