Abstract

EL-KOSASY, A. M.; HUSSIEN, L. A.  and  ABDEL-RAHMAN, M. H.. New Approach for Measuring Antioxidant Activity Via a Graphite Sensor. Port. Electrochim. Acta [online]. 2014, vol.32, n.5, pp.395-403. ISSN 0872-1904.  https://doi.org/10.4152/pea.201405325.

An ion selective membrane sensor from dioctyl phthalate as a plasticizer in a polymeric matrix of polyvinyl chloride (PVC) and β-cyclodextrin as an ionophore was constructed and evaluated according to IUPAC recommendations. Linear Nernstian response of DPPH^• within the concentration ranges of 10^-6 to 10^-2 mol L^-1 was obtained with average recovery 99.87 ± 0.617. Nernstian slope of 58.5 mV/decade with excellent selectivity over the pH range of 3-8 was observed. The suggested method was standardized using butylated hydroxyl anisole (BHA). The 50% radical scavenging activity (IC50) determined by the proposed sensor correlated well with that of the common spectrophotometric method based on scavenging of 2,2-diphenyl-1picrylhydrazyl (DPPH^•). An algorithm implemented in Microsoft Visual Basic® 6.0 was used for calculating (IC50) values which are 7.38 μg/mL ± 0.35, 89.98 μg/ mL ± 0.45 and 1.45 mg/ mL ± 1.50 for BHA, Paracetamol and Dipyridamole, respectively. The proposed sensor represents a simple and reproducible tool for measuring DPPH^• scavenging activity of Paracetamol and Dipyridamole in bulk powder, pharmaceutical formulations and simulated intestinal fluid (SIF) without sophisticated separation techniques.

Keywords : Sensor; antioxidant; Paracetamol; Dipyridamole.

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