Fluorometry of hydrogen peroxide using oxidative decomposition of folic acid
Hydrogen peroxide (H2O2) is one of the most important reactive oxygen species. In the present study, a fluorometry method for detecting H2O2 utilizing folic acid was evaluated. Folic acid was decomposed by H2O2 in the presence of Cu(II) into pterine-6-carboxylic acid, leading to strong fluorescence enhancement. In the absence of the metal ion, superoxide and H2O2 could not decompose folic acid. Also, H2O2 plus sodium hypochlorite (a source of singlet oxygen) could not induce fluorescence enhancement. These results demonstrate that H2O2 can be selectively detected using folic acid plus Cu(II). The limit of detection (LOD; at S/N=3) for H2O2 is 0.5 μM. This method based on the fluorescence enhancement of folic acid was applied in order to determine small amounts of H2O2 generated through the autooxidation of semicarbazide (generation rate: ∼0.01 μM min−1), a carcinogenic compound.
KeywordsHydrogen peroxide Reactive oxygen species Fluorometry Folic acid Copper(II) ion
The author wishes to thank Professor Motoshi Nakamura (Faculty of Engineering, Shizuoka University) for his helpful discussion. This work was supported by a Grant-in-Aid for Scientific Research on Priority Areas (417) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese Government.
- 3.Soh N (2006) Anal Bioanal Chem (accepted)Google Scholar
- 4.Lei W, Duerkop A, Lin Z, Wu M, Wolfbeis OS (2003) Microchim Acta 143:269–274Google Scholar
- 9.Cadet J, Douki T, Gasparutto D, Ravanat JL (2003) Mutat Res 531:5–23Google Scholar
- 12.Hirakawa K, Mori M, Yoshida M, Oikawa S, Kawanishi S (2004) Free Radical Res 38:439–447Google Scholar
- 24.Hirakawa K, Midorikawa K, Oikawa S, Kawanishi S (2003) Mutat Res 536:91–101Google Scholar