Conductometric Flow‐Injection Glucose Biosensing System with an Immobilized Glucose‐Oxidase Mini‐Reactor

Abstract

Abstract A flow‐injection conductometric manifold equipped with an immobilized glucose‐oxidase mini‐reactor was proposed for the determination of glucose concentration. The glucose of the injected sample plug was oxidized enzymatically to its δ‐lactone, and the hydrolysis of the lactone generated a concentration‐dependent flow‐injection signal. The dynamic range was from the tens of μM to the mM order of glucose; the immobilized enzyme reactor was stable for at least several months. The pH of the carrier solution was maintained in a slightly alkaline region (ca. 8.0 by 500 μM of Tris‐HCl) to accelerate the spontaneous hydrolysis of δ‐gluconolactone. The repeatability of the flow‐injection signals was improved (CV < 3%, n = 7) by the addition of Triton X‐100® (0.7% w/v) into the carrier solution.