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 biologica l surface modification procedures for beads such as graphite and magnetic p articles are reviewed. The most reported biosensing configurations based on beads are biosensors and bioreactors integrated into bead injection (BI) a nalytical systems. In the first case, the bioparticles ave trapped on the t ransducer surface and both the biochemical reaction and the electrochemical transduction occur at the same location on the BI system. In the bioreacto r configuration the bioparticles are trapped before the transducer and the biochemical reaction products are detected downstream in a separate electro chemical detector. (C) 2001 Published by Elsevier Science B.V.