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SINGLET‐OXYGEN GENERATION AT GAS‐LIQUID INTERFACES: A SIGNIFICANT ARTIFACT IN THE MEASUREMENT OF SINGLET‐OXYGEN YIELDS FROM OZONE‐BIOMOLECULE REACTIONS
Author(s) -
Kanofsky Jeffrey R.,
Sima Paul D.
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb09570.x
Subject(s) - singlet oxygen , biomolecule , ozone , chemistry , oxygen , photochemistry , singlet state , excited state , organic chemistry , biochemistry , physics , nuclear physics
— Several ozone‐biomolecule reactions have previously been shown to generate singlet oxygen in high yields. For some of these orone‐biomolecule reactions, we now show that the apparent singlet‐oxygen yields determined from measurements of 1270 nm chemiluminescence were artifactually elevated by production of gas‐phase singlet oxygen. The gas‐phase singlet oxygen results from the reaction of gas‐phase ozone with biomolecules near the surface of the solution. Through the use of a flow system that excludes air from the reaction chamber, accurate singlet‐oxygen yields can be obtained. The revised singlet‐oxygen yields (mol 1 O 2 per mol O 3 ) for the reactions of ozone with cysteine, reduced glutathione, NADH, NADPH, human albumin, methionine, uric acid and oxidized glutathione are 0.23 ± 0.02, 0.26 ± 0.02, 0.48 ± 0.04, 0.41 ± 0.01, 0.53 ± 0.06, 1.11 ± 0.04, 0.73 ± 0.05 and 0.75 ± 0.01, respectively. These revised singlet‐oxygen yields are still substantial.