Determination of Contents of Catechins in Oolong Teas by Quantitative Analysis of Multi-components Via a Single Marker (QAMS) Method

The catechins in oolong tea are related to its flavor and health benefits. In this paper, a new strategy for a quantitative analysis of multi-components via a single marker (QAMS) was developed and validated to analyze six catechins (epigallocatechin, catechin, epicatechin, epigallocatechin gallate, gallocatechin gallate, and epicatechin gallate) in oolong tea by HPLC. Catechin was chosen as the internal reference substance. The relative correction factors (RCFs) between catechin and the other five catechins were investigated for the QAMS calculation using five different types of chromatographic columns. Meanwhile, the content of each of the six analytes was also determined by a conventional external standard method. Finally, the angle cosine value revealed that there was no significant difference between the QAMS method and the external standard method. The QAMS method established in this study solved the problem of the availability and high cost of some standard substances and would be useful for providing an efficient and feasible quality assessment method for oolong tea and other botanic samples.