Determination of oil-soluble tea polyphenols in oil by solid phase extraction and Folin-Ciocalteu colorimetry

Objective To establish a simple and accurate method for determination of oil-soluble tea polyphenols. Methods The oil-soluble tea polyphenols in oil were extracted by solid phase extraction column, and then eluted by acid methanol. The oil-soluble tea polyphenols were transformed into water-soluble tea polyphenols by saponification, and then determined by Folin-Ciocalteu colorimetry. Results The linear equation of this method was Y=0.0007X-0.0381, R2=0.9566. The recoveries were 82.7%～84.8% and the relative standard deviations(RSDs) were about 5%, which can satisfied the routine analysis. Conclusion This method is simple, and need no complex analysis instrument. The analysis results are reliable and it can be used for the determination of oil-soluble tea polyphenols in edible oil.