Abstract: Rh6G can produce its characteristic fluorescence with its excitation and emission wavelength at 350nm and 549nm,respectively. Rh6G was oxidized by hydroxyl radical rapidly and its fluorescence were quenched. Extractives of vegetable mighteliminate hydroxyl radical in solution, hence its weakening effect of fluorescence of solution will be minimized. Based on thisprinciple, a new method was developed to determine the eliminating ratio of hydroxyl radical in vegetables. The antioxidativeactivities of 14 kinds of vegetbles were thus determined. The results showed that the antioxidative activity of Spinach was thestrongest, followed by Rape,Chinese leeks, Coriander and Potherb musterd. All of them had green leaves.

Key words: fluorescent spectrophotometry, vegetable, hydroxyl radical, Rh6G