design of an electrochemical sensor for non-enzymatic detection of glucose using a mixed ag/nio-ag/nis as a modifier

Abstract: diabetes is a group of metabolic diseases caused by high glucose levels [1]. this disease, over time, causes significant damage to many of the body's systems, particularly the nerves and blood vessels. current glucose sensors in the market use enzymes as an active material and modifier. these sensors have intrinsic chemical and thermal sensitivity. a wide variety of enzyme-free sensors, including transition metals, have attracted attention among the various modifications of glucose electrochemical sensors due to their low cost and ubiquity on the earth [2]. metal oxide sensors can be a suitable alternative to enzymatic sensors with a longer lifetime [3]. monitoring glucose through sweat can simplify the work and provide data for more accurate diagnosis and treatment [4]. this work reports a non-enzymatic glucose sensor based on doping ag in nio and nis (ag/nio-ag/nis) nanocomposite compounds. modifier was synthesized by hydrothermal method, the carbon paste electrode was modified with it and used as working electrode. the platinum wire, ag/agcl electrode were used as counter and reference electrode in this work. ag/nio-ag/nis was characterized using scanning electron microscopy (sem), energy-dispersive x-ray spectroscopy (edx), electrochemical impedance spectroscopic (eis), and x-ray diffraction (xrd). the electrocatalytic activity of the modifier was investigated by cyclic voltammetry, and the differential pulse voltammetry technique was applied for monitoring glucose in alkaline media. the proposed sensor has a linear range from 1 μm to 4 mm with a detection limit of 0.23 μm, and also displays excellent selectivity, stability, and reproducibility. finally, the sensor was successfully applied to detect glucose in human sweat as a real sample.