A Total Transmitted Light Intensity Method for Detecting Concentration of Glucose Aqueous Solution Directly Irradiated by Near Infrared LED

Abstract

Glucose plays an important role in biological fermentation and biosensing. Therefore, it is very important to detect the concentration of glucose aqueous solution quickly and accurately. A novel method for detecting the concentration of glucose solution is introduced in this article. Based on the spectral characteristics of the near-infrared light-emitting diode (NIR LED), the total transmitted light intensity (TTLI)-concentration model of glucose solution directly irradiated by NIR LED was established to detect the concentration of glucose solution. In this model, firstly, the TTLI of glucose solution and TTLI of deionized water were defined. Secondly, the definition formula of the change ratio of TTLI was provided. Finally, the linear relationship between the change ratio of TTLI and the concentration of glucose solution was derived. In order to verify the effectiveness of the TTLI method, NIR LED Glucose Solution Concentration Detection System (NIR LED-GSCDS) was designed. In this system, an alternating measurement method is designed to reduce the influence of the radiation fluctuation of the NIR LED light source on the accuracy of detection results, and the thermostatic circulation subsystem is designed to reduce the influence of the change of solution temperature on the infrared light absorption rate of glucose solution. The experimental results show that the linear correlation coefficient between the change rate of TTLI and glucose solution concentration is 0.998 and the relative uncertainty is 8.2% in the concentration range of 1000–5000 mg/dL. Therefore, the TTLI method can determine the concentration of glucose solution under the direct irradiation of the NIR LED light source without a complex spectroscopic system.