烟用香精UPLC指纹图谱的夹角余弦、相关系数与欧氏距离评价

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

以Acquity UPLC TMBEHC C18柱作色谱柱,硝基苯为内标,乙腈-0.1%甲酸水溶液为流动相,检测波长254nm,采用超高效液相色谱(UPLC)法测定了10种烟用香精6批次样品、稀释品和掺兑品,而后采用相对保留值和相对峰面积法对所有成分的保留时间和色谱峰进行处理,建立了烟用香精UPLC指纹图谱,再用夹角余弦、相关系数与欧氏距离法对UPLC指纹图谱进行处理,并通过比较各批次香精样品的夹角余弦、相关系数与欧氏距离接近程度评价这些香精质量的稳定性。结果表明:夹角余弦、相关系数和欧氏距离都能够在一定程度上反映出烟用香精的质量变化,而夹角余弦和相关系数的差异不大,且比较相似,但在小量浓度变化上表现不明显,而欧氏距离则能反映香精浓度和种类的变化。

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-O. 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.