EXPERIMENTAL-EVIDENCE OF THE CHAOTIC REGIME IN A SALICYLATE BIOSENSOR

In a biosensor for salicylate, developed using a modified carbon paste electrode with silica gel coated with Meldola's Blue and salicylate h ydroxylase, the current time series presented a complex oscillatory pa ttern, for salicylate and NADH concentrations close to 2.0 X 10(-5) an d 3.6 X 10(-5) mol l(-1), respectively. These experimental results sug gest that the biosensor response presents chaotic characteristics. The complex temporal behavior of these series was diagnosed as determinis tic chaos by measurement of the Grassberger-Procaccia dimension, and t he calculation of the first Lyapunov exponent. The value determined fo r the correlational dimension is lower than 5. These results suggest a coupling of five or six differential equations to describe the redox reactions of the biosensor system.