Engineered photoelectrochemical platform for rational global antioxidant capacity evaluation based on ultrasensitive sulfonated graphene-TiO2 nanohybrid.

Dietary antioxidants as health promoters for human beings have attracted much attention and triggered tremendous efforts in evaluation of the antioxidant capacity. Unfortunately, no versatile detection system has been designed to date. Due to the possible synergistic effect among antioxidant components in a diversified system, to isolate and quantify an individual antioxidant via a chromatography approach limits the scope for global antioxidant activity assay. Quality inspections with a spectroscopy strategy to any colored food are far from satisfactory. Herein, a photoelectrochemical (PEC) platform with an ultrasensitive titanium dioxide decorated sulfonated graphene (SGE-TiO2) based transducer was introduced for antioxidant monitoring. Under an open circuit potential (zero potential), with extraordinary response, excellent reproducibility and stability, this PEC sensor could be successfully applied for rational analysis of the global antioxidant capacity. Such a highly efficient strategy showed advantages such as simplicity, convenience, high sensitivity and universality, which were also applicable to the detection of colored system. Moreover, the PEC sensor could be employed for practical evaluation of antioxidant capacity of teas. The concerned mechanism was further proposed and adequately discussed. This straightforward yet powerful approach provides a general format for dietary antioxidant assessment in foodstuff industries.