engleski

A novel amperometric method for antioxidant activity determination using DPPH free radical

A new method for determination of antioxidant activity based on amperometric reduction of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) at the glassy carbon electrode is proposed. All experiments were done in three-electrode electrochemical cell at 140 mV vs. Hg2Cl2│ 3 M KCl using ethanolic solution (j = 40%) and 0.033 M KCl in 0.033 M phosphate buffer pH = 7.4. Obtained linear range for Trolox in 100 µ M DPPH ethanol-water solution was up to 30 µ M with a limit of detection of 0.05µ M. The developed method was applied to the evaluation of antioxidant activity for some water or ethanol soluble pure compounds of antioxidants and for samples of tea, wine and beverages. The good correlation of measurements (R2 = 0.9993) expressed as Trolox equivalent was obtained between proposed amperometric method and classic spectroscopic method.

amperometric detection; antioxidant; DPPH; trolox equivalent

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