Separation of catechin compounds by retention theory in RP-HPLC

An efficient optimization method was used to separate catechin compounds by RP-HPLC. In this work, the binary mobile phase of water and acetonitrile was used with the buffer of acetic acid (AA). The elution profiles were calculated by the plate theory based on the linear and quadratic equations of retention factor, lnk = Ink(w) + SF, lnk = L + MF + NF2, k = A + B/F, where F was the vol.% of acetonitrile. We modified the retention theory to calculate the elution profile in both isocratic and gradient modes. The final calculated results showed that the first mobile phase composition was water in 0.1% AA/acetonitrile in 0.1% AA, 90/10 vol.%, followed 30 min later by the second composition of mobile phase, which was linearly changed to 70/30 vol.%. In the experimental conditions, the agreement between the experimental data and the calculated values was relatively good. Catechin compounds from Korean and Chinese green tea as potential powers of anticancer and antioxidant components were target materials in this work. The full content of the catechin compounds of EGC, (+) C, EC, EGCG, and ECG in Chinese green tea extracted was 249.92 mg/g, so it was 2.15 times of that from Korean tea.