A novel electrochemical micro-titration method for quantitative evaluation of the DPPH free radical scavenging capacity of caffeic acid

Abstract In this report, the stoichiometric ratio ( R ) for interaction of diphenylpicrylhydrazyl (DPPH) radicals with antioxidant was employed as an evaluation index DPPH radical scavenging activity antioxidants. This related only to relationship and had no initial amount sample volume, which could offer a solution problem poor comparability EC 50 values under different conditions. A novel electrochemical micro-titration method proposed determination antioxidant. model verified using caffeic acid scavenger, determined be in range 2.003–2.046. The calculated were 0.513, 1.011, 1.981 × 10 –5 mol/L 2.10, 4.05, 8.02 –7 moL added radicals, respectively. showed differences from conventional method, but better precision reliability, used smaller sample.