"25310" . "I, S" . "RIV/00216275:25310/13:39896383" . . "60254" . "CS - St\u00E1tn\u00ED svaz Srbska a \u010Cern\u00E9 Hory" . "Kalcher, Kurt" . "Amperometric Enzyme Carbon Paste-Based Biosensor for Quantification of Hydroquinone and Polyphenolic Antioxidant Capacity"@en . . "S\u00FDs, Milan" . . "7" . "[553F074B537E]" . . "8" . "Pekec, Bruna" . "11"^^ . . "Vyt\u0159as, Karel" . "RIV/00216275:25310/13:39896383!RIV14-MSM-25310___" . . . "http://www.electrochemsci.org/papers/vol8/80709030.pdf" . . . "Amperometric Enzyme Carbon Paste-Based Biosensor for Quantification of Hydroquinone and Polyphenolic Antioxidant Capacity" . "1452-3981" . "Amperometric Enzyme Carbon Paste-Based Biosensor for Quantification of Hydroquinone and Polyphenolic Antioxidant Capacity"@en . . . . . . "An amperometric biosensor for the determination of hydroquinone and other polyphenolic antioxidants is presented, based on a carbon paste electrode on which tyrosinase is immobilized in a Nafion (R) film. In a 0.1 M phosphate buffer (pH 7.0 and 25 +/- 1 degrees C), the antioxidant capacity can be expressed as the concentration equivalent of p-hydroquinone (HQ), according to an amperometric response of polyphenolic antioxidants with the carbon paste sensor at -0.24 V vs. Ag/AgCl/3 M KCl. In the range of low HQ concentrations (up to 120 mu mol L-1), the corresponding calibration curve follows the equation I [mu A] = -0.0426 -0.0113 c(HQ) [mu mol L-1] with a correlation coefficient R = 0.999. The limit of detection (LOD for S/N = 3) was estimated as 1.6 mu mol L-1, the repeatability was 1.2 % RSD (c = 90 mu M, n = 5 measurements). The biosensor can be applied to determine the phenolic antioxidant capacity in plants and food samples in the absence of higher concentrations of ascorbic acid."@en . "Amperometric Enzyme Carbon Paste-Based Biosensor for Quantification of Hydroquinone and Polyphenolic Antioxidant Capacity" . . . "4"^^ . "An amperometric biosensor for the determination of hydroquinone and other polyphenolic antioxidants is presented, based on a carbon paste electrode on which tyrosinase is immobilized in a Nafion (R) film. In a 0.1 M phosphate buffer (pH 7.0 and 25 +/- 1 degrees C), the antioxidant capacity can be expressed as the concentration equivalent of p-hydroquinone (HQ), according to an amperometric response of polyphenolic antioxidants with the carbon paste sensor at -0.24 V vs. Ag/AgCl/3 M KCl. In the range of low HQ concentrations (up to 120 mu mol L-1), the corresponding calibration curve follows the equation I [mu A] = -0.0426 -0.0113 c(HQ) [mu mol L-1] with a correlation coefficient R = 0.999. The limit of detection (LOD for S/N = 3) was estimated as 1.6 mu mol L-1, the repeatability was 1.2 % RSD (c = 90 mu M, n = 5 measurements). The biosensor can be applied to determine the phenolic antioxidant capacity in plants and food samples in the absence of higher concentrations of ascorbic acid." . . . "International Journal of Electrochemical Science" . "red wine analysis; hydroquinone; antioxidant capacity; tyrosinase; biosensor; amperometry; carbon paste electrode"@en . "2"^^ . "000323547600010" . . . .