Amperometric Enzyme Carbon Paste-Based Biosensor for Quantification of Hydroquinone and Polyphenolic Antioxidant Capacity

作者：Sys Milan^*; Pekec Bruna; Kalcher Kurt; Vytras Karel

来源：International Journal of Electrochemical Science, 2013, 8(7): 9030-9040.

• carbon paste electrode
• amperometry
• biosensor
• tyrosinase
• antioxidant capacity
• hydroquinone
• red wine analysis

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.

• 出版日期2013-7