Clay‐Enhanced Electrochemiluminescence and Its Application in the Detection of Glucose

Clay‐modified electrodes were prepared with montmorillonite K10 and characterized in their ability to enhance the electrogenerated chemiluminescence (ECL) in a solution containing luminol and hydrogen peroxide. Montmorillonite K10 proved to be an effective catalyst for such a purpose, according to the anodic current and ECL intensity measured with the electrodes with and without clay particles. Under optimum conditions (pH 10 and 0.8 V vs. SCE), the ECL was enhanced by a factor of 10. Control experiments showed the enhanced ECL is likely due to a facilitation in the oxidation of luminol and by the iron species contained in the clay. Double‐step potential techniques suggested that superoxide is very likely to be the key reactive oxygen species involved in the clay‐enhanced ECL reaction. In addition, clay/luminol/ GO x electrodes were constructed by using aminopropyltrimethoxysilane as an immobilizing agent for the detection of glucose. Although the electrode sensitivity decreased by ca. 15% after 10 days, a linear calibration curve was attained, covering the concentrations of glucose from 10 μM to 0.5 mM with a detection limit at ca. 10 μM at pH 10.