Catechol detection by a tyrosinase electrode.

by Durand, Monique; Paul, David W.

This project investigated the operational stability and sensitivity for tyrosinase biosensors using a bulk modified carbon paste electrode and tyrosinase immobilized in Nafion on a glassy carbon electrode. The gradual loss in sensitivity for catechol was determined using a tyrosinase carbon paste electrode in an amperometric flow injection system. Over a period of 33 days the maximum sensitivity was 20.6nA/uM catechol, and the lowest sensitivity observed was 0.99nA/uM catechol at day 33. A successful attempt was made to construct a tyrosinase/Nafion glassy carbon electrode. Cyclic voltammetry was used to study the stability and sensitivity of tyrosinase modified and unmodified glassy carbon electrodes for detection of 10mM catechol in 0.1M phosphate buffer pH 6.5. The sensitivity obtained for the tyrosinase/Nafion-modified electrode was exceptionally greater than the unmodified glassy carbon electrode. However, the operational stability attained was only three (3) hours.