Development of a rapid, accurate and efficient HPLC method for simultaneous determination of catechins and theaflavins in black tea

Catechins and theaflavins, as the primary bioactive constituents of black tea, have a significant impact on its color, aroma, and flavor profile. We developed a rapid and precise method using HPLC to detect catechins and theaflavins in black tea. The method employed 0.1% formic acid-acetonitrile (phase A) and 1% formic acid-water (phase B) as mobile phases. Separation occurred on an Agilent SB-C18 column (4.6 mm x 250 mm, 5 mu m), with 20 mu L injection volume. Detection took place at 30 degrees C with a flow rate of 1 mL/min for 55 min.Quantitative determination utilized the external standard method, exhibiting high sensitivity (limit of detection: 0.19 to 5.14 mu g/mL) and a strong linear correlation (R2 >= 0.9993) between concentration range and peak area. Precision, repeatability, and stability were excellent, with relative standard deviations (RSDs) below 5% (n = 5). The average recovery rate of standard addition ranged from 98.02% to 102.57%, with an RSD of less than 3.17% (n = 5). In summary, this straightforward, efficient, and precise approach is well-suited for both qualitative and quantitative analysis of catechins and theaflavins in tea. It overcomes the limitations of previous methods, providing a valuable tool for evaluating the quality and composition of black tea.