Determination of Polyphenol in Water Chestnut Peel by Folin-Ciocalteu Method

According to GB/T8313-2008(determination of total polyphenols in tea),the total polyphenols(TP) content in water chestnut peel was analyzed by spectrophotometry with Folin-Ciocalteu reagent and standard of Gallic acid.The method of GB / T8313-2008 was improved and verified in the aspects of wavelength,reagent,stability,linearity and reproducibility,respectively.The regressive equation of standard curve was y=0.012x-0.001(r=0.999 4).The optimal determination conditions could be well calculated according to the absorption at 765 nm by reacting 0.20 mL 1 mol.L-1 Folin-Ciocalteu with 0.15 mL 10% Na2CO3 for 80 min at 25℃.In this method,the TP contents in water chestnut peel and RSD were 4.86% and 1.03%(n=6),respectively.The average recovery was 99.5%(RSD=0.269%,n=6).As a result,the improved method was convenient,fast,accurate and reliable for the determination of TP in water chestnut peel.