Evaluation of UPLC Fingerprint Spectrum of Tobacco Flavor with Included Angle Cosine,Correlation Coefficient and Euclidean Distance Methodologies

Six batches of 10 tobacco flavor samples,their dilutions and mixtures were detected by ultra performance liquid chromatography(UPLC) with TUV detector at the wavelength of 254 nm and Acquity UPLC^TM BEHC C₁₈ column,using acetonitrile-0.1% formic acid aqueous solution as mobile phase at gradient elution mode and nitrobenzene as an internal standard substance.The UPLC fingerprint spectrums were developed by processing the retention times and chromatographic peak areas of all the components in flavor samples with relative retention value and relative peak area methodologies,and further processed by Euclidean distance,included angle cosine and correlation coefficient methodologies.By comparing the values of the flavor from different batches,the quality consistence of the flavor was evaluated.The results showed that the variation of flavor quality could be characterized by Euclidean distance,included angle cosine and correlation coefficient to a certain extent.The included angle cosine did not differ much from correlation coefficient,they were more similar to each other and less sensitive to the minor concentration variations of flavor;while Euclidean distance could characterize the kind and concentration changes of flavors.