Electrochemical Spectroscopy: A Novel Technique for Trace-Level Glucose Detection

This letter proposes a novel electrochemical spectroscopic technique for selective detection of glucose in solution using NiWO4 nanostructured receptor layers deposited on interdigitated structures to fabricate two terminal resistive devices. On exposing the device to glucose in solution (10-50 mmol/L) in a cell configuration with the sensor as the working electrode and analyzing the second derivative of the obtained I-V plot, four monotonically increasing peaks were observed, respectively, at 0.2, 1.2, 1.4, and 2.4 V in the second-harmonic (d(2)I/dV(2) versus V) plot. The spectrum obtained was very specific to glucose, and the peaks were attributed to glucose solution over potential, electrolytic potentials of water and glucose solution, and hydroperoxy intermediate formation resulting from the NiWO4-glucose and NiWO4-H2O interactions. The device response was calculated from the monotonic variations of the peak intensities in the positive voltage range and current in the negative voltage range with positive voltage peak responses of 28.6 and 5.05 times at 0.3 and 2.5 V, respectively, positive voltage peak inversion responses of -3.9 and -5.34 times at 1.1 and 1.4 V, respectively, and negative voltage response of 2.1 times for 50 mmol/L of glucose. When exposed to a mixed solution, the sensor presented a spectrum specific to glucose. Thus, the proposed technique and the device propose a novel solution for a practically usable ultraselective sensor and solve the selectivity issues of conventional conductometric sensors.