1. Department of Material and Chemical Engineering, Guilin University of Technology, Guilin 541004, China 2. Department of Resource and Environmental Science, Guangxi Normal University, Guilin 541004, China
Abstract：In HCl-NaAc buffer solution, the hydroxy free radical from the Fenton reaction is captured by excess KI and releases I-3. The I-3 combines with Rhodamine B(RhB, λmax=554 nm), Rhodamine 6G(Rh6G, λmax=526 nm), Rhodamine S(RhS, λmax=526 nm), and butyl Rhodamine B(b-RhB, λmax=556 nm) to form association particles, so the absorbance at max wavelength decreases. The concentration of hydroxy free radical (calculated by the concentration of hydrogen peroxide) is proportional to the decreased absorbance of the systems of RhB, Rh6G, RhS, b-RhB in the range of 0.136-0.680 μg·mL-1, 0.034-0.680 μg·mL-1, 0.034-0.680 μg·mL-1, 0.034-0.680 μg·mL-1, respectively. Based on this fact, a new method for the determination of scavenging percentage of hydroxy free radical with antioxidant was developed. The resistance to oxidation of four substances and six kinds of tea extract were measured with satisfactory results.
