A biosensor with myrosinase and glucose oxidase bienzyme system for determination of glucosinolates in seeds of commonly consumed vegetables

A biosensor for determination of glucosinolates has been fabricated by employing a bienzyme system composed of myrosinase and glucose oxidase immobilized onto an eggshell membrane and a dissolved oxygen electrode as the transducer. The detection scheme was based on the enzymatic reactions of glucosinolates leading to the depletion of the dissolved oxygen level in the base solution and then the decrease in the oxygen level was monitored and related to the glucosinolates concentration. The effects of bienzyme ratio, pH, ascorbic acid concentration, phosphate buffer concentration and temperature on the response of the glucosinolates biosensor were investigated. Storage and repeatability of the biosensor were also studied in detail. The analytical range of the biosensor was from 2.5 × 10−5 to 7.5 × 10−4 mol/L glucosinolates and the time taken to reach a steady signal was about 100 s. Common matrix interferents such as tartaric acid, glycine, oxalic acid, succinic acid, dl-α-alanine, adipic acid, dl-cysteine, calcium chloride and sodium chloride did not give significant interference. The glucosinolates content in seeds of commonly consumed vegetables was determined, and the results were satisfactory.