One-Shot Chemiluminescence Biosensor for Determination of Glucose in Soft Drinks

Abstract

The preparation of a new biosensor for glucose was based on the fact that glucose can be determined by its enzymatic oxidation to gluconic acid with simultaneous formation of hydrogen peroxide in the presence of glucose oxidase. Hydrogen peroxide formed in previous reaction further reacts with luminol in presence of cobalt as catalyst producing chemiluminescence signal. This biosensor was made of three layers. The first layer contained luminol, sodium phosphate, sodium lauryl sulphate as a surfactant and a polymer, hydroxyethyl cellulose as a carrier applied to the support. The second was an aqueous solution of Co2+ as a catalyst, and the third layer was an aqueous solution of glucose oxidase. After applying the sample solution (glucose) by micropipette onto the sensor, glucose reacted with glucose oxidase and hydrogen peroxide was formed. Hydrogen peroxide diffused towards the polymeric layer containing luminol and produced chemiluminescence reaction. The detection limit for the new glucose biosensor (3σ) was found to be 19 mg L-1 glucose (σ from 5 determinations of 30 mg L-1). A relative standard deviation of 7.6 % was recorded for 10 measurements of 50 mg L-1 standard glucose solution, and 6.8 % for 10 measurements of 500 mg L-1 standard glucose solutions. The glucose biosensor was used for the determination of glucose in soft drinks (mainly apple juices). The results obtained with the chemiluminescence sensors and commercial glucometer (as the reference method) are in good agreement. The corresponding recovery rates were between 93 and 105 %.