Study on Paofupian, Heishunpian and Baifupian by Two-dimensional Infrared Correlation Spectroscopy

Paofupian, Heishunpian and Baifupian, three kinds of Radix Aconiti Lateralis Preparata with different processing procedures, were identified fast and nondestructively by Fourier Transform Infrared spectroscopy (FTIR) combined with Two-Dimensional Infrared Correlation Spectroscopy (2D FTIR) in this paper. The three kinds of samples were similar to each other in one-dimensional IR spectra but quite different in 2D FTIR spectra. In the range between 900 and 1 500 cm-1, one strong autopeak was aroused by Paofupian around 1 220 cm-1 in synchronous spectrum, whereas three autopeaks not only at 1 220 cm but also at 1 200 cm-1 and 1 400 cm-1 were aroused by Heishunpian and Baifupian. Also the autopeak at 1 400 cm-1 in Baifupian was stronger than that of Heishunpian. It can be seen clearly that the crosspeaks in these synchronous spectra were quite different too. It is proved that the 2D FTIR could serve in distinguishing Paofupian, Heishunpian and Baifupian. Therefore, the fast and accurate property of 2D FTIR makes it a powerful and new approach to identifying the different procedures to process medicinal herbs.