Dual-index sequence analytical method for IR fingerprint spectra of the chloroform extract of Radix Glycyrrhizae Comparison research on FTIR fingerprint of Salvia priontis based on fourier transform infrared spectroscopy combined with multistatistical analysis Determination methods of content uniformity in preparations of Chinese materia medica FTIR fingerprint spectrograms of traditional Chinese medicine Marsdenia tenacissima Identification of Chinese traditional medicine Angelicae Pubescentis Radix from different places by fourier transform infrared spectrometry Studies on IR fingerprint of Tongren Dahuoluo pills and Tongren Niuhuangqingxin pills