New materials for electrochemical sensing III. Beads

The analytical use of beads as new materials for electrochemical sensing is described. The general physical and chemical characteristics and biological surface modification procedures for beads such as graphite and magnetic particles are reviewed. The most reported biosensing configurations based on beads are biosensors and bioreactors integrated into bead injection (BI) analytical systems. In the first case, the bioparticles are trapped on the transducer surface and both the biochemical reaction and the electrochemical transduction occur at the same location on the BI system. In the bioreactor configuration the bioparticles are trapped before the transducer and the biochemical reaction products are detected downstream in a separate electrochemical detector. © 2001 Published by Elsevier Science B.V.