Electrochemical biosensor for catechol using agarose–guar gum entrapped tyrosinase

An electrochemical biosensor using tyrosinase was constructed for the determination of catechol. The enzyme was extracted from a plant source Amorphophallus companulatus and entrapped in agarose–guar gum composite biopolymer matrix. Catechol was determined by direct reduction of biocatalytically liberated quinone species at −0.1 V versus Ag/AgCl (3 M KCl). The response was found to be linear and concentration dependent in the range of 6 × 10−5 to 8 × 10−4 M with a lower detection limit of 6 μM. It has reusability up to 20 cycles and a shelf life of more than 2 months when stored at 4 °C.