Reduction of nitro blue tetrazolium by CO/sub 2//sup -/ and O/sub 2//sup -/ radicals

Journal Article · Thu Apr 17 04:00:00 EST 1980 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100445a006· OSTI ID:5218579

Bielski, B H.J.; Shiue, G G; Bajuk, S

The reduction of nitro blue tetrazolium (NBT/sup 2 +/) by CO/sub 2//sup -/ and O/sub 2//sup -/ has been studied by the stopped-flow method and the pulse-radiolysis technique. Both reductants form the tetrazolinyl radical, and the rate constants are k/sub NBT/sup 2 +/ + CO/sub 2//sup -// = (6.4 +- 0.2) x 10/sup 9/ M/sup -1/ s/sup -1/ and k/sub NBT/sup 2 +/ + O/sub 2//sup -// = (5.88 +- 0.12) x 10/sup 4/ M/sup -1/ s/sup -1/. In the absence of other reactants, the tetrazolinyl radicals (NBT/sup +/.) disappear by a pH-dependent second-order disproportionation reaction to produce monoformazan (MF/sup +/) and nitro blue tetrazolium (NBT/sup 2 +/) ions. The tetrazolinyl radical (NBT/sup +/.) has an absorption maximum at 405 nm with a pH-independent molar extinction coefficient epsilon/sub 405nm/ = 15,000 +- 350 M/sup -1/ cm/sup -1/. Monoformazan (MF/sup +/) has an absorption maximum at 530 nm; its molar extinction coefficient varies from epsilon/sub 530 nm/ = 25,400 +- 1200 M/sup -1/ cm/sup -1/ at pH 9.5-11.0 to epsilon/sub 530nm/ = 12,800 +- 640 M/sup -1/ cm/sup -1/ at pH 5.7-6.7. Mechanisms for the overall reaction are discussed.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 5218579
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 84:8; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ABSORPTION SPECTRA
AZOLES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DATA
DATA FORMS
DECOMPOSITION
ELECTRONS
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
INFORMATION
ISOLATED VALUES
KINETICS
LEPTONS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION KINETICS
REDUCTION
SPECTRA
SUPEROXIDE RADICALS
TETRAZOLES
TETRAZOLIUM