Voltage-controlled enzyme-catalyzed glucose–gluconolactone conversion using a field-effect enzymatic detector

Abstract

The field-effect enzymatic detection (FEED) technique was used to control the kinetics of the enzymatic conversion of glucose to gluconolactone. The glucose–gluconolactone conversion occurring at an enzyme-immobilized electrode, a well-studied process, was confirmed using mass spectrometry. Electrochemical studies showed that the glucose oxidation current depends on the gating voltage V_G and the ion concentration of the sample solution. Additionally, the depletion of glucose in the sample also showed a dependence on V_G. FEED was used to detect H₂O₂ on the zepto-molar level in order to show the ultrasensitive detection capability of the technique. These results, while providing evidence for the proposed mechanism of FEED, indicate that V_G controls the conversion process. The effect of V_G on the glucose–gluconolactone conversion was demonstrated by the observed V_G-dependent kinetic parameters of the conversion process.