Determination of the characteristic wavelengths of photoacoustic glucose signals based on interval partial least square algorithm

Abstract

Glucose detection by means of the photoacoustic spectroscopy was performed in this paper. A set of photoacoustic detection system of glucose based on pulsed laser induced ultrasonic detection was established. Based on the photoacoustic system, a series of photoacoustic detection experiments for glucoses with different concentrations were performed. The time-resolved photoacoustic signals and photoacoustic peak-to-peak values of glucose under the excitation wavelengths of pulsed laser from 1300nm-2300nm were obtained. In order to get the optimal absorption wavelengths of glucose, the difference spectrum of photoacoustic peak-to-peak values between the glucoses and the pure water were used. At the same time, the interval partial least square algorithm was used to get the optimal absorption wavelength regions. The integrated wavelength region was divided into 10-15 sub-regions. For each sub-region, the model of partial least square was established, and the cross-validation method was also used. Results show that the wavelength regions of 1350-1440nm and 1490-1550nm are the optimal characteristic wavelength region. The prediction models were established in the optimal wavelength regions, four components of the partial least square algorithm were used. In the chosen optimal wavelengths, the correction coefficient between the glucose predicted concentration and original concentration can reach 0.9879 and 0.9969, respectively, the root mean square error of cross validations (RMSECV) are about 12.5mg/dl and 6.2mg/dl, respectively, the concentration bias is about 0.0581mg/dl, and 2.09mg/dl, respectively.