Discrimination of adulterated traditional chinese medicines by infrared Spectroscopy-Two dimensional correlation analysis

A new method was established, based on infrared spectroscopy-two dimensional (2D) correlation analysis, for the discriminative analysis of adulteration in traditional Chinese medicines (TCM). Fenfluramine hydrochloride (FH) and sibutramine hydrochloride (SH) were taken as examples of synthetic drugs (adulterant), and the correlative peaks of their synchronous 2D correlation spectra were found. Then the characteristics of the synchronous 2D correlation spectrum of the suspected TCM were compared with those of FH. Since the correlative peaks in the synchronous spectrum of the suspected TCM coincide well with those of FH, a positive conclusion could be drawn after further investigation of the asynchronous spectra of TCM, which could provide the information about the source of correlative peaks. On the contrary,the dissimilarity of the synchronous spectra of SH and TCM directly implies that the suspected TCM is not adulterated with SH. The method can be used for a correct discrimination on whether the TCM is adulterated with the synthetic drugs, it does not rely on sample separation, and provides a new simple and cost-effective alternative to test the adulteration of TCM.