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

KeyWord:dark tea  high performance liquid chromatography(HPLC)  fingerprint  random forests  producing area  discriminate analysis

Abstract:

      A fingerprint method was established for the analysis of Hunan Anhua dark tea by high performance liquid chromatography(HPLC).Samples were extracted with water at 90 ¡æ thermostat water bath for 20 min.The analysis was performed on a C18 column(5 ¦Ìm,4.6 mm¡Á250 mm)using methanol-water(containing 0.1% phosphoric acid) as mobile phase by gradient elution at a flow rate of 1.0 mL/min.The detection wavelength was set at 270 nm.The compounds in the dark tea were well separated,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 component 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 Anhua dark tea and other dark teas were visually represented,and some important components were also discovered.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.