Multi-steps Infrared Macro-fingerprint Analysis for thermal processing of Fructus viticis

The procedure of toasting process of Fructus viticis was tracked and studied by Fourier transform infrared spectroscopy combined with two-dimensional correlation analysis. It was shown that IR spectra of various F. viticis forms, ranging from crude to charred have their own macroscopic fingerprints, and their second derivative spectra have even more useful fingerprints. Likewise, we discovered there are many characteristic fingerprints in 2D IR spectra. According to these three steps of macroscopic fingerprint spectra, not only F. viticis and its thermally processed drugs were discriminated directly and effectively. Furthermore, it is shown that during the processing the content of its lipids were decreased continually while that of flavonoids were reduced much more slowly, which brought on the phenomenon that the comparative content of flavonoids was increased firstly and decreased afterwards. Simultaneously, according to the differences of locations and intensities of auto-peaks in 2D IR spectra, the integral changes of interior components during the processing are revealed. This method, having its high resolution and excellent macroscopic fingerprint features, can fast and effectively identify and discriminate samples without separation and extraction. The trend of integrated changes in complicated mixture matrixes can be reflected directly via the technique. Consequently, it is recommended to apply this method to guide the processing and quality control of F. viticis or even potentially the entire Chinese traditional medicine system.