CONICET | Buscador de Institutos y Recursos Humanos

The analytical response of amperometric glucose electrodes was explained in the framework of theproperties of hydrogels with different muc/chit ratio at pH ¼ 7.00 used as immobilization matrix forglucose oxidase. The continuous increase in the sensitivity of the electrodes with the amount of chitosanwas attributed to a more efficient crosslinking without affecting the enzyme activity. The results werecompared with those obtained using the same matrices to immobilize Oxalate Oxidase at pH ¼ 2.85where it has the highest activity. A maximum sensitivity at muc/chit 70/30 ratio for these oxalateelectrodes was observed. Decrease in permeability of negatively charged oxalate with the chitosancontent in the matrices, in spite of the high partition coefficient, explains the analytical differences withglucose electrodes. Swelling and viscoelasticity of the hydrogels allowed to asses the importance ofa hydrophilic environment for the enzyme in both cases.