Non-linear dielectric spectroscopy: antifouling and stabilisation of electrodes by a polymer coating

Non-linear dielectric spectroscopy (NLDS) has previously been shown to prod uce quantitative information that is indicative of the metabolic state of v arious organisms, by modeling the non-linear effects of their membranous en zymes on an applied oscillating electromagnetic field using supervised mult ivariate analysis methods. However, the instability of the characteristics of the measuring apparatus rendered the process temperamental at best in th e laboratory and impractical for field use. The main practical problem, of the non-stationarity of the electrode-soluti on interface and the ease with which the electrode surfaces are subject to protein fouling. It is addressed by applying a thin, electrically transpare nt antifouling coat to the electrodes. This reduces the interminable cleani ng procedures previously required to prepare the electrodes for use. increa ses their usable lifetime before recleaning, and also improves the precisio n and linearity of multivariate models on NLDS data. (C) 2000 Elsevier Scie nce S.A. All rights reserved.