Iwahashi H, Parker C E, Mason R P, Tomer K B
Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709.
Rapid Commun Mass Spectrom. 1990 Sep;4(9):352-4. doi: 10.1002/rcm.1290040912.
Radical adducts of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) with hydroxyl, methanol-derived, and ethanol-derived radicals were detected by a combination of liquid chromatography with either electron paramagnetic resonance or thermospray mass spectrometry (LC/EPR or LC/TSP-MS) in the Fenton system (with methanol or ethanol). One radical adduct was observed in the reaction of DMPO with the hydroxyl radical or the methanol-derived radical, while two adducts were detected in the reaction of DMPO with ethanol-derived radicals. The LC/TSP-MS spectra showed quasi-molecular ions [M + H]+ at m/z 146 and m/z 160 for the methanol-derived and ethanol-derived radical adducts, respectively, and an apparent molecular ion M+ at m/z 130 for the hydroxyl radical adduct. Use of methyl-D3 alcohol (CD3OH) and ethyl-D5 alcohol (CD3CD2OH) indicated that carbon-centered radicals are formed. Experiments with partially deuterated ethanol (CD3CH2OH and CH3CD2OH) indicated that the two adducts observed in the reaction of DMPO with ethanol-derived radicals correspond to the two diastereomeric adducts of DMPO with the alpha-hydroxyethyl free radical.
在芬顿体系（含甲醇或乙醇）中，通过液相色谱与电子顺磁共振或热喷雾质谱联用（LC/EPR或LC/TSP-MS）检测了5,5-二甲基-1-吡咯啉N-氧化物（DMPO）与羟基、甲醇衍生自由基和乙醇衍生自由基的自由基加合物。在DMPO与羟基自由基或甲醇衍生自由基的反应中观察到一种自由基加合物，而在DMPO与乙醇衍生自由基的反应中检测到两种加合物。LC/TSP-MS光谱显示，甲醇衍生和乙醇衍生自由基加合物的准分子离子[M + H]+分别在m/z 146和m/z 160处，羟基自由基加合物的表观分子离子M+在m/z 130处。使用甲基-D3醇（CD3OH）和乙基-D5醇（CD3CD2OH）表明形成了以碳为中心的自由基。用部分氘代乙醇（CD3CH2OH和CH3CD2OH）进行的实验表明，在DMPO与乙醇衍生自由基的反应中观察到的两种加合物对应于DMPO与α-羟乙基自由基的两种非对映体加合物。
