高效液相色谱指纹图谱及随机森林应用于湖南安化黑茶水溶性成分的研究

Investigation on Fingerprint of Hunan Anhua Dark Tea's Water-soluble Components by High Performance Liquid Chromatography and Random Forest

建立了适用于湖南安化黑茶的高效液相色谱指纹图谱分析方法。样品用水在90℃恒温水浴中浸提20min,以C18色谱柱(250 mm×4.6 mm,5μm)分离,甲醇-0.1%磷酸溶液为流动相梯度洗脱,检测波长为270nm,流速为1.0 m L/min,黑茶的各种组分得到较好分离,共确定18个色谱峰作为安化黑茶的特征指纹峰,并通过对照品分析对其中12个峰进行确证。运用相似度评价、主成分分析、正交偏最小方差判别分析(Orthogonal partial least squares discriminant analysis,OPLS-DA)和随机森林法对78个黑茶样品指纹图谱进行了化学模式识别研究和变量重要性判定。结果表明联合指纹图谱分析法和随机森林法可有效区分湖南安化黑茶和其他产地的黑茶。该方法操作简单,精密度、稳定性和重现性良好,为安化黑茶的鉴别和质量控制提供了实验依据。

A fingerprint method was established for the analysis of Hunan Anhua dark tea by high per- formance liquid chromatography （HPLC）. Samples were extracted with water at 90℃C thermostat water bath for 20 min. The analysis was performed on a C18 column （5 μm, 4. 6 mm ×250mm）using methanol -water（containing 0. 1% phosphoric acid） as mobile phase by gradient elution at a flow rate of 1.0 rnL/min. The detection wavelength was set at 270 nm. The compounds in the dark tea were well sep- arated, and 18 common peaks in chromatograms were selected as characteristic peaks, in which 12 peaks were identified by the standards. Four pattern recognition methods, similarity evaluation, principal com- ponent analysis, OPLS - DA and random forest were used to analyze HPLC chromatograms of 78 batches of dark tea samples which originated from Hunan province and other provinces. The differences between An- hua dark tea and other dark teas were visually represented, and some important components were also dis- covered. The results showed that different origins of dark tea had an obvious difference. The proposed method is simple and of good precision, stability and repeatability. This investigation could provide the fundamental data for identification and quality-assessment of Hunan Anhua dark tea.