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Singlet Oxygen Detection in Skim Milk by Electron Spin Resonance Spectroscopy
Author(s) -
Bradley D.G.,
Lee H.O.,
Min D.B.
Publication year - 2003
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2003.tb05700.x
Subject(s) - chemistry , electron paramagnetic resonance , oxygen , riboflavin , singlet oxygen , nitroxide mediated radical polymerization , skimmed milk , spectroscopy , photochemistry , analytical chemistry (journal) , resonance (particle physics) , nuclear magnetic resonance , chromatography , organic chemistry , biochemistry , physics , food science , radical polymerization , quantum mechanics , particle physics , polymer , copolymer
2,2,6,6‐Tetramethyl‐4‐piperidone (TMPD) can react with singlet oxygen to produce the corresponding nitroxide, 2,2,6,6‐tetramethyl‐4‐piperidone‐1‐oxyl (TAN), which can be detected by electron spin resonance (ESR) spectroscopy. ESR detected the formation of TAN in 5 μM riboflavin phosphate buffer, or skim milk containing 20 mM TMPD during illumination. The effects of illumination, riboflavin, and oxygen on the formation of TAN indicated that the presence of each was required for singlet oxygen formation. The photo reduced riboflavin might reduce TAN to the hydroxylamine of TAN, thus decreasing the paramagnetic TAN signal. Maximum concentration of TAN was obtained at an added 10 mM riboflavin in buffer solution or in skim milk after 15 min of illumination in the presence of oxygen.