Original scientific paper
https://doi.org/10.5599/jese.2012.0024
Development of an electrochemical sensor for the determina-tion of the total antioxidant capacity in berries based on boron doped diamond
Bruna Pekec
; Institute of Chemistry, Department of Analytical Chemistry, Karl-Franzens University, Graz, Austria
Birgit Feketefoldi
; Joanneum Research Forschungsgesellschaft mbH - Materials, Weiz, Austria
Volker Ribitsch
; Joanneum Research Forschungsgesellschaft mbH - Materials, Weiz, Austria
Astrid Ortner
; Institute of Pharmaceutical Science, Department of Pharmaceutical Chemistry, Karl-Franzens University, Graz, Austria
Kurt Kalher
; Institute of Chemistry, Department of Analytical Chemistry, Karl-Franzens University, Graz, Austria
Abstract
Many antioxidants can be electrochemically oxidized using graphite-based electrodes; nevertheless problems arise due to the strong adsorption of redox species at the sensing area. We have demonstrated that boron doped diamond (BDD) electrodes do not show this property, which can be exploited for the design of a new amperometric sensor for the quantification of antioxidants as “total antioxidant capacity” (AOC). As reference substances hydroquinone (HQ) and 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) were studied in more detail. The supporting electrolyte was a phosphate buffer solution (PBS, 0.1 mol/L, pH 7.0). The limits of detection (LOD) were 1.5 mg/L and 2.5 mg/L for HQ and Trolox, respectively. The repeatability was 3 % RSD for concentration of 200 mg/L HQ. The method could be applied for the determination of AOC in different berry samples, such as strawberry, blueberry, grape and bramble. A comparison with a standard photometric assay showed good correlation between both methods. The BDD sensor features good reproducibility without fatiguing over at least two months of operation.
Keywords
Boron doped diamond electrode; total antioxidant capacity; amperometric sensor; berry extracts
Hrčak ID:
96896
URI
Publication date:
6.2.2013.
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