The Establishment And Application Of DAD-HPLC Method For Six Major Catechins In Tea

The article uses RP-HPLC system to explore and optimizate the HPLC separation and detection conditions for the target catechins standards and samples, and these factors include the choice by which eluent method, the optimization of the mobile phase type and proportion, pH value, types of additives, injection volume and so on. The final separate conditions can separate the target catechins from the complex matrix of tea samples whose conditions are the wave length at210nm, pH value3.0with RP-gradient eluent method.The sample extraction is aimed at the total contents of six kinds of target catechins.At high temperature condition the extraction contents of the target catechins are usually high but they are easy to be oxidated. According to the characteristics, the pretreatment method of the tea samples is optimized. This pretreatment method uses a certain concentration of the aqueous solution of anti-oxidants ascorbic acid to inhibit the oxidation of the target catechins in order to improve the extraction rate. The experimental results show that the total contents of target substance are375.80μg/mL which is higher than the national standard method as well as traditional methods.Method validation is a very important part of the testing and improving methods, including peak of specificity, accuracy, precision, linearity, range, limit of detection, limit of quantification and stability studies. The results show that within the scope of the method in the verification, the validation target are all well and different actual tea samples are analyzed on this basis.This method can satisfy the qualitative and quantitative requirements.This paper establishes and develops a DAD-HPLC analysis and detection method for the6kinds of target catechins in tea, and this method has certain reference value for them.