Classification of Chinese tea leaves using laser-induced breakdown spectroscopy combined with the discriminant analysis method

Six types of tea leaves, including Longjing green Tea, Mengding Huangya, white tea, Tie Guanyin, Wuyi black tea and Pu'er tea, were analyzed and identified using laser-induced breakdown spectroscopy (LIBS) combined with the discriminant analysis (DA) method. The spectral line intensities of Mg, Mn, Ca, Al, Fe, K, CN (0-0) and C2 (0-0) referenced to C I 247.86 nm were selected as the analysis indexes according to the differences in the LIBS spectra. The results show that 294 samples were identified correctly from a 300 training set and the average correct identification rate was 98%. In addition, 286 samples from a 300 testing set were correctly identified and the average correct identification rate was 95.33%. The misclassification mainly occurred among Mengding Huangya tea, white tea and black tea due to the little differences in the line intensities of Mg, Mn, Ca, Al and C2 (0-0) among these tea leaves. The research results provide a reference method for the identification of tea leaves.