Electron spin resonance of spin-trapped radicals of amines and polyamines. Hydroxyl radical reactions in aqueous solutions and γ-radiolysis in the solid state

1982 ◽  
Vol 60 (12) ◽  
pp. 1493-1500 ◽  
Author(s):  
Magdi M. Mossoba ◽  
Ionel Rosenthal ◽  
Peter Riesz
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Room Temperature ◽  
Spin Trap ◽  
Alkyl Chain ◽  
Spin Trapping ◽  
Radical Reactions ◽  
Hydrogen Atoms ◽  
Protonated Amino Group ◽  
Spin Resonance

The reactions of hydroxyl radicals with methylamine, dimethylamine, trimethylamine, diethylamine, sec-butylamine, ethylenediamine, 1,3-diaminopropane, putrescine, cadaverine, 1,7-diaminoheptane, ornithine, spermidine, spermine, agmatine, and arcaine in aqueous solutions have been investigated by spin-trapping and esr. Hydroxyl radicals were generated by the uv photolysis of H2O2 and 2-methyl-2-nitrosopropane (MNP) was used as the spin-trap. The effects of ionizing radiation on the same polyamines in the polycrystalline state were also investigated. The free radicals produced by γ-radiolysis of these solids at room temperature in the absence of air were identified by dissolution in aqueous solutions of MNP. The predominant reaction of [Formula: see text] with amines and polyamines below pH 7 was the abstraction of hydrogen atoms from a carbon that is not adjacent to the protonated amino group. For agmatine and arcaine which contain guanidinium groups abstraction occurred from the α-CH. Dimethylamine was oxidized to the dimethylnitroxyl radical by H2O2 in the dark. γ-Radiolysis of polyamines in the polycrystalline state generated radicals due to H-abstraction from either the α-CH or from a carbon atom in the middle of the alkyl chain. The deamination radical was obtained from ornithine.

Spin trapping of the azide radical with nitroso compounds

1982 ◽  
Vol 60 (12) ◽  
pp. 1597-1597 ◽  
Author(s):  
Walter Kremers ◽  
Grant W Koroll ◽  
Ajit Singh
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Nitroso Compounds ◽  
Spin Traps ◽  
Spin Resonance

Azide radicals (N3·) are formed in aqueous solutions by the reaction of hydroxyl radicals (·OH) with azide anions (N3aq−). Azide radicals have been spin trapped with three nitroso spin traps: nitrosodurene (ND), 2,6-dideutero-3,5-dibromo-4-nitrosobenzene sulfonate (DDNBS), and 2-methyl-2-nitrosopropane (MNP). The electron spin resonance (esr) spectra show the presence of two molecules of the spin traps in the spin-trapped species.

Studies on γ-irradiated aqueous solutions of amino acids with functional groups by the spin-trap high-performance liquid chromatography – electron spin resonance method

1984 ◽  
Vol 62 (9) ◽  
pp. 1722-1730 ◽  
Author(s):  
Naohisa Iguchi ◽  
Fumio Moriya ◽  
Keisuke Makino ◽  
Souji Rokushika ◽  
Hiroyuki Hatano
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
High Performance ◽  
Spin Trap ◽  
Resonance Method ◽  
The Other ◽  
Spin Resonance ◽  
Electron Spin Resonance Method

Aqueous solutions of L-glutamine, L-asparagine, sodium L-glutamate, sodium L-aspartate, L-serine, and L-threonine were γ-irradiated in the presence of a spin trap, 2-methyl-2-nitrosopropane. Stable spin adducts produced in the irradiated solutions were analyzed by the spin-trap hplc–esr method. The spin adducts of the following short-lived radicals were found and identified: H2NCOCH2CH2ĊHCOO− (1), [Formula: see text] and [Formula: see text] for L-glutamine; [Formula: see text] (2) for L-asparagine; −OOCCH2CH2ĊHCOO− (3) and [Formula: see text] for sodium L-glutamate; −OOCCH2ĊHCOO− (4) and [Formula: see text] (5) for sodium L-aspartate; [Formula: see text] and HOCH2ĊHCOO− (6) for L-serine; CH3CH(OH)ĊHCOO− (7) and [Formula: see text] for L-threonine. The free radicals, 1, 3, 4, 6, and 7, were due to the reaction of the hydrated electron [Formula: see text] with these amino acids and the other adducts were due to the attack of hydroxyl radical (•OH). The two diastereomeric pairs of spin adducts of the short-lived radicals, 2 and 5, could be individually separated by the technique utilized.

Electron spin resonance studies of the reactions of sorbate with nitrite in the presence of a spin trap

1982 ◽  
Vol 60 (12) ◽  
pp. 1598-1601 ◽  
Author(s):  
Avinash Joshi ◽  
Dennis M Hinton ◽  
George C Yang
Keyword(s):  
Electron Spin Resonance ◽  
Double Bond ◽  
Sodium Nitrite ◽  
Spin Trap ◽  
Spin Trapping ◽  
Potassium Sorbate ◽  
Radical Product ◽  
Rapid Decomposition ◽  
Esr Spectrum ◽  
Spin Resonance

An esr spectrum was generated when a spin trap, t-nitroso butane (tNB), was added to potassium sorbate solution at pH of 6.4. This spectrum can be explained by the abstraction of allylic hydrogen by NO2, generated by the decomposition of tNB, followed by spin trapping of the radical product. With increasing concentration of NO2, which was accomplished by either the addition of sodium nitrite or by lowering the pH to cause rapid decomposition of tNB, a different esr spectrum was observed. This spectrum can be accounted for by a radical formed by addition of NO2 to the 4,5 double bond of the sorbate and subsequent trapping by tNB.

scholarly journals Photolysis of Hydrogen Peroxide, an Effective Disinfection System via Hydroxyl Radical Formation

2010 ◽  
Vol 54 (12) ◽  
pp. 5086-5091 ◽  
Author(s):  
Hiroyo Ikai ◽  
Keisuke Nakamura ◽  
Midori Shirato ◽  
Taro Kanno ◽  
Atsuo Iwasawa ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Bactericidal Activity ◽  
Laser Light ◽  
Irradiation Time ◽  
Spin Trapping ◽  
Oral Bacteria ◽  
Test Species ◽  
Spin Resonance ◽  
Resonance Spin ◽  
The Relationship

ABSTRACT The relationship between the amount of hydroxyl radicals generated by photolysis of H2O2 and bactericidal activity was examined. H2O2 (1 M) was irradiated with laser light at a wavelength of 405 nm to generate hydroxyl radicals. Electron spin resonance spin trapping analysis showed that the amount of hydroxyl radicals produced increased with the irradiation time. Four species of pathogenic oral bacteria, Staphylococcus aureus, Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Enterococcus faecalis, were used in the bactericidal assay. S. mutans in a model biofilm was also examined. Laser irradiation of suspensions in 1 M H2O2 resulted in a >99.99% reduction of the viable counts of each of the test species within 3 min of treatment. Treatment of S. mutans in a biofilm resulted in a >99.999% reduction of viable counts within 3 min. Other results demonstrated that the bactericidal activity was dependent on the amount of hydroxyl radicals generated. Treatment of bacteria with 200 to 300 μM hydroxyl radicals would result in reductions of viable counts of >99.99%.

Electron spin resonance study of spin-trapped azide radicals in aqueous solutions

1980 ◽  
Vol 58 (15) ◽  
pp. 1592-1595 ◽  
Author(s):  
Walter Kremers ◽  
Ajit Singh
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Sodium Azide ◽  
Electron Spin Resonance Study ◽  
Spin Traps ◽  
Spin Resonance ◽  
Hyperfine Splittings ◽  
Spin Resonance Study

Organic spin traps have been used to study the formation of azide radicals during the reaction of azide anions with hydroxyl radicals. The azide radicals have been successfully trapped with three spin traps: 5,5-dimethylpyrroline-1-oxide (DMPO), phenyl-N-tert-bulyl nitrone (PBN), and 4-pyridyl-N-tert-butyl nitrone (PyBN). The azide radicals produced from 15N sodium azide have also been trapped. The hyperfine splittings of the resulting radicals have been determined.

Homolytic Scission of Interunitary Bonds in Lignin Induced by Ultrasonic Irradiation of MWL Dissolved in Dimethylsulfoxide

Holzforschung ◽  
2000 ◽  
Vol 54 (4) ◽  
pp. 357-364 ◽  
Author(s):  
Aki Yoshioka ◽  
Teruyuki Seino ◽  
Masayoshi Tabata ◽  
Mitsuo Takai
Keyword(s):  
Ultrasonic Irradiation ◽  
Spin Trap ◽  
Spin Trapping ◽  
Spin Adduct ◽  
Dmso Solution ◽  
Picea Jezoensis ◽  
Spin Resonance ◽  
Spin Trapping Technique ◽  
Secondary Carbon ◽  
Stable Nitroxide

SummaryAn electron spin resonance (ESR) method combined with a spin trapping technique was applied to trap and characterize unstable radicals which were generated by ultrasonic irradiation of the dimethylsulfoxide (DMSO) solution of a softwood, Yezo Spruce (Picea jezoensiscarr.) lignin. It was found that an unstable secondary carbon radical, ~CH • in the solution was trapped as the stable nitroxide spin adduct when the DMSO solution was subjected to ultrasonic irradiation in the presence of a spin trapping reagent: 2,4,6-tri-tert-butylnitrosobenzene (BNB) at 50°C for 30 min. This means that the alkyl phenyl ether bonds, ~CH-O-phenyl, known as interunitary bonds in lignins were homolytically cleaved by the ultrasonic irradiation, although the phenoxy radical Ph-O •, called guaiacoxy radical, i.e. the counter radical of the secondary carbon radical, was not trapped by the BNB spin trap. This suggests that the trapping of the guaiacoxy radical, having a methoxy group in anortho-position, by the BNB molecule, carrying two bulky butyl groups in theortho-positions, is sterically hindered.

Sign in / Sign up

Export Citation Format

Share Document