Polyamide column chromatography is a good way for clean-up
of tea samples, and was used to analyze tea samples. The common
method is a two-step of elution, firstly a washing step with pure
water, then with 100% methanol to recover the FOG from the tea
brew. Considering the difference of polarity of catechins and
FOG, we add one more step of elution to separate them. After
trying a series of the organic solvents, 60% methanol was selected
as the best solution.