Identification of Amino Acids and Their Hydrates by Terahertz Spectral

• 1、Materials and Textiles College,Zhejiang Sci-Tec University,Hang Zhou 310018

Abstract：Terahertz（THz） spectroscopy is very sensitive to the collective vibrational mode of molecules and weak interaction between molecules. Therefore, the identification of anhydrous and hydration states of molecular can be realized according to the difference of terahertz absorption spectra. In this paper, the technique of terahertz time-domain spectroscopy (THz-TDS) was used to detect the anhydrous and hydrated forms of four kinds of amino acids (glycine, L-alanine, L-serine, L-tyrosine)owning different polarities. Based on the results mentioned above,We find that there is a significant difference between the absorption spectrums of amino acids and corresponding their Hydrate, and the degree of difference mentioned above is positively correlated with the amino acid hydrophilicity index. Furthermore,In ordertoverify the recognitionsuperiority and accuracy of experimental results of terahertz spectroscopy , Fourier transform infrared spectroscopy（FTIR）, thermogravimetric analysis （TG）and X-ray diffraction techniques（XRD） were used to characterize and analyze the four groups of amino acid from perspective of molecular groups, thermodynamic properties and crystal structure.

Keywords： Material physics and chemistry terahertz time-domain spectroscopy amino acid water of crystallization absorption peak