Development and analytical application of a glucose biosensor based on glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle-immobilized onion inner epidermis

A glucose biosensor comprising a glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle (O-HTCC NP)-immobilized onion inner membrane and a dissolved oxygen (O₂) sensor has been successfully developed. The detection scheme is based on the depletion of dissolved O₂ content upon exposure to glucose. The decrease in O₂ level was monitored and related to the glucose concentration. The biosensor shows linear response to glucose from 0.0 to 0.60mM with a detection limit of 50μM (S/N=3). The effect of O-HTCC NP and enzyme loading, pH, temperature, and phosphate buffer concentration on the sensitivity of the biosensor was studied in detail. The biosensor exhibits fast response time (70s), good repeatability (3.2%, n=10) and storage stability (90% of initial sensitivity after 3-week storage). Common interferents including acetic acid, lactic acid, propionic acid, butyric acid, folic acid, methanol, glycine, dl-α-alanine and dl-cysteine do not cause significant interferences on the biosensor. The proposed biosensor method was successfully applied to determine the glucose content in real samples such as orange juice, red wine and tea drink and the results were comparable to that obtained from a spectrophotometric method. The glucose recovery test demonstrates that the proposed glucose biosensor offers an excellent, accurate and precise method for the determination of glucose in real samples.