Identification of Viola yedoensis Makino and Viola inconspicua by FT-IR

The different extracts and of Viola yedoensis Makino and Viola inconspicua were analyzed and identified by Fourier transform infrared spectroscopy(FT-IR). One-dimensional infrared spectrum showed that the extracts of Viola yedoensis Makino and Viola inconspicua contained the aromatics, volatile substances and glycosides, with not significant differences from each other. However, different extraction sites of the two medicinal materials in second derivation spectrum were obviously different, especially the number of automatic peaks and peak intensity in the range of 970- 800 cm^-1. Viola yedoensis Makino displayed 5 automatic peaks, 6 automatic peaks and 6 automatic peaks, while Viola inconspicua displayed 7 automatic peaks, 4 peaks, 4 peaks in the second derivation spectrum of petroleum ether extraction site, chloroform extraction site and the ethyl acetate extraction site. In addition, the peak position of the strongest peak in the second derivative of the ethyl acetate extraction site was 1 467 cm^-1, while the strongest peak of the Viola inconspicua was at 1 384 cm^-1, so the two medicinal materials can be distinguished by the strongest peak position of ethyl acetate extraction site in second derivation spectrum. Studies demonstrated that one-dimensional infrared spectroscopy combined with the second-order derivative analysis could achieve the accurate identification between Viola yedoensis Makino and Viola inconspicua. This research provides new ideas and new methods for the identification of Viola and other adulterants.