| Hollow titania nanoshells (HTNSs), synthesized by SiO2-sacrificed template method, was devoted to intensify the electrochemiluminescence (ECL) of luminol. The size, shell-thickness and the crystal phase which were all important factors about the efficiency can be controlled by adjusting the template size, precursor concentration and calcination temperature, respectively. The structure of HTNSs was characterized by transmission electron microscopy, scanning electron microscopy and X-ray diffraction spectroscopy, etc. After the optimization, the HTNSs was modified onto the surface of indium tin oxide (ITO) coated glass to act as a working electrode of a flow injection analytic system. The experimental results demonstrated a150times high ECL emission than on bare ITO.The research also revealed that the ECL of luminol on this modified electrode showed very sensitive responses toward hydrogen peroxide with a detection limits of4.62×10-10M at pH8.0phosphate buffer solution. The modified electrode was used to determinate antioxidants by quenching. With resveratrol as index the gross antioxidant content of garlic were determined by521,892,2006(mg resveratrol/kg garlic), with satisfactory recoveries between87.6%and108.3%. Compared with the Phosphomolybdenum method, it demonstrated the feasibility of electrochemiluminescence. Besides the discussion on the intensifying mechanism of the HTNSs for ECL of luminol, it was successfully applied to evaluate the gross antioxidant activity of garlic. |
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