Comparative Study of Different Near-Infrared (NIR) Wavelengths on Glucose Concentration Detection

Abstract

There are a lot of in-vitro non-invasive techniques to measure a glucose concentration and one of them is by using near-infrared (NIR) spectroscopy. In this study, the main objective is to compare the behaviour on the different wavelengths of NIR transmitter (1050 nm, 1200 nm, 1300 nm, 1450 nm, and 1550 nm) on different glucose concentration solutions (0 to 300 mg/dL) and the measurement indicates a correlation between voltage and glucose concentration. The conditional circuit of NIR transmitter and detector is designed in order for the transmitter to transmit an optimal intensity of light. Besides, it also consists of the filter and amplifier used to filter and amplify the signal from the noise on the detector side. The transmitter and detector are positioned facing each other and the cuvette that filled with glucose solution is located in between. A placeholder casing for the experimental setup is designed to reduce an external error during the data collection. The voltage outputs are recorded for every different glucose concentrations by using different transmitter wavelength. Based on the results, it shows that the voltage output reading is directly proportionate to the glucose concentrations. These behaviours are similar to all different transmitter wavelengths used. The R-square (R2) and root-mean-square error (RMSE) for every wavelength used are varied. The result of using 1450 nm wavelength shows the best correlation between voltage outputs and glucose concentrations compared to other wavelengths with the highest value of R2. A linear equation is extracted from the fitted graph and can be used to predict the value of glucose concentrations.