抄録
Fluorometric determination for hydrogen peroxide based on the formation of thiochrome was studied. Thiochrome is oxidation product of thiamine and gives intense fluorescence. Though bromine cyanide or pottasium ferricyanide has been generally used as oxidizing agent of thiamine, it was proved that hydrogen peroxide was useful as oxidizing agent. Then, hydrogen peroxide can be determined from the quantity of produced thiochrome. The analytical procedure was as follows ; to a sample solution containing a proper quantity of hydrogen peroxide, 1 ml of thiamine (30μg/ml), peroxidase (10 units/ml), and sodium hydroxide solution (20%) were added. The mixture was stood for 30 minutes at room temperature and saturated with sodium sulfate. Ten ml of isobutanol was further added and shaken to extract thiochrome produced here. Fluorescence intensity of the separated isobutanol after treatment with sodium sulfate was measured (λEx ; 375 nm, λEm ; 430 nm). The calibration curve was linear up to H2O2 0.2μg/tube. On the basis of the proposed method, remaining hydrogen peroxide in Japanese noodle (udon) could be determined with the recovery of 90.6% and coefficient of variation of 1.1%.
