The Determination of Glucose Based on Terahertz Spectroscopy

Glucose is one of the most important organic molecules in life activities. It is significant to study the absorptive fingerprints of glucose in terahertz band and carry out quantitative and qualitative analysis research. Terahertz is specific for macromolecules. As for the rotational and vibrational modes within a molecule, when terahertz spectra penetrate the macromolecules, they have fingerprints in terahertz wavelength. This feature can be used to identify macromolecules. In this paper, D-glucose anhydrous was selected as the research object. Terahertz time-domain spectrum of D-glucose anhydrous was measured using Terahertz time-domain spectroscopy technique first and then the frequency domain spectrum was calculated with Fast Fourier Transform (FFT). The method of the Dorney and Duvillaret were used to process the frequency spectra to get the absorption coefficient. The absorption features of D-glucose anhydrous samples were studied and then mathematical models of quantitative relations between D-glucose levels and its absorptive spectroscopy were estimated. The results showed that, D-glucose anhydrous has remarkable absorptive fingerprints in terahertz band, and the regression model based on sample fingerprints using multivariate linear regression method performed well when compared with the partial least squares method. Its correlation coefficient and the error of mean square root of the calibration set model was 0. 977 2 and 0. 061 6 respectively, and the correlation coefficient and the error of mean square root the of the prediction set model was 0. 992 7 and 0. 055 2 respectively, which showed that terahertz time-domain spectroscopy technique can be used for quantitative and qualitative analysis of D-glucose anhydrous. It provides a reference for applications of rapid detection of the glucose content in fruits, vegetables, food and medicine in future using terahertz spectroscopy.