engleski

Electrochemical determination of total polyphenols content in apple peel extracts

The aim of this study was to examine electrochemical properties of quercetin (a flavonoid widely distributed in fruits and vegetables, e.g. apples, broccoli, red onions, plums etc.) in different electrolytes and to use quercetin as a standard for electrochemical detection of total polyphenols content in apple peel extracts. Electrochemical properties of quercetin were studied in three different electrolytes (KCl, NaCl, LiCl) by differential pulse voltammetry (Ic = 0.34 mol dm-3). Measurements were conducted in a three electrode voltammetric cell in an aqueous media. Glassy carbon was used as a working electrode, platinum wire as counter electrode and Ag/AgCl electrode as a reference electrode. Inert atmosphere was acomplished by system purging with high purity argon Ar 5 (fi(Ar) = 99.999 %), before each measurement. Differential pulse voltammograms of quercetin revealed three oxidation peaks in all three electrolytes, which were associated with oxidation of five -OH groups of quercetin. The first oxidation peak of quercetin was chosen for quantification of total polyphenols content since linear dependence of Ip vs. quercetin concentration was found in all three electrolytes. The best calibration diagram (R2= 0.9924) was obtained in 0.34 mol dm-3 KCl solution in quercetin concentration range from 1.0∙10-6 mol dm-3 to 1.6∙10-5 mol dm-3. So this diagram was used for quantification of total polyphenols in apple peel extracts.

apple peel extracts ; differential pulse voltammetry ; quercetin ; total polyphenols content determination

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