Optical Sensors for Glucose Based on Glucose Oxidase and Congo Red Immobilized Onto Transparent Membranes

ABSTRACT

The aim of the present investigation is to obtain membranes with immobilized indicator (congo red) as well as simultaneously immobilized indicator and enzyme (glucose oxidase) which can be used for further determination of glucose concentrations in model solutions. As a result of the enzyme reaction the acid formed changes the colour of the indicator which is in proportional dependence on his absorption in a certain range of molar glucose concentration. The use of acetylcellulose membrane with covalently immobilized indicator and free enzyme as well as simultaneously immobilized indicator and enzyme proved to be successful for determination of glucose in the range of 50–600 mM The membranes are stable and can be used many times. The possible mechanism of congo red immobilization on the activated membrane is discussed.