Quantitative 31P NMR detection of oxygen-centered and carbon-centered radical species

Argyropoulos, Dimitris S.; Li, Hongyang; Gaspar, Armindo R.; Smith, Kamilah N.; Lucia, Lucian A.; Rojas, Orlando J.

doi:10.1016/j.bmc.2006.02.009

Cited by 36 publications

(41 citation statements)

References 23 publications

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“…12 these results differ from those of Khramstov et al, 11 where the authors studied the trapping of a methyl radical with DEPMPo. the nitroxide methyl radical adduct after decay was detected by .…”

Section: Carbon-centered Radicalscontrasting

confidence: 91%

“…In many case the products of the decomposition reactions are the corresponding hydroxylamine c and nitrone d. these species (c and d) are actually 31 P NMr detectable and the chemical shift of the phosphorous atom has been shown to be related to the nature of the radical being trapped. [12][13][14] Moreover, compounds c and d could be characterized by gas chromatography-mass spectrometry (Gc-MS) thus elucidating and confirming their structures. During this work, we determined the chemical structure of the DIPPMPo radical adducts after the decay reactions by subjecting the diamagnetic species to gas chromatographymass spectrometry techniques and we studied their fragmentation pathways.…”

Section: Europeanmentioning

confidence: 94%

“…this technique was termed "NMr spin trapping" by Khramtsov et al 11 31 P NMr could be exploited to perform quantitative analyses in the presence of a suitable internal standard and qualitative analyses since the chemical shift of the 31 P atom was found to be strongly dependent on the nature of the adducts. [11][12][13][14] to further confirm the identity of the spin adducts, complementary analytical techniques that provide additional information about the structure of such adducts need to be used. Mass spectrometry (MS) has been shown to be a suitable tool to identify and verify spin adducts.…”

Section: Europeanmentioning

confidence: 99%

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Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance

Zoia

Argyropoulos

2010

Eur J Mass Spectrom (Chichester)

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All rights reserved EuroPEAN JourNAL of MASS SPEctroMEtry for many years, spin traps have been used to decrease the reactivity of free radicals in order for them to be identified and detected by electron paramagnetic resonance (EPr) spectrometry, thereby allowing the acquisition of abundant information on the production of such species in biological, biochemical and chemical systems. [1][2][3][4] During this technique, a highly reactive free radical typically reacts with a double bond of a diamagnetic compound (the spin trap) to form a more stable radical (the spin adduct) which can be detected by EPr spectrometry. [5][6][7][8][9] Nitrones are the most frequently used compounds as spin trapping agents, and the spin adducts being, in this case, a nitroxide. recent accounts 10 have demonstrated that phosphorus-containing spin traps give rise to radical adducts that have longer half-lives compared Characterization of free radical spin adducts of 5-diisopropyloxy-phosphoryl-5-methyl-1-pyrroline-N-oxide using mass spectrometry and 31 P nuclear magnetic resonance 5-Diisopropyloxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO) was used to trap a variety of free radicals and the stable compounds generated by the natural decomposition of the initially formed spin adducts were characterized by 31 P nuclear magnetic resonance (NMR) and mass spectrometry. Initially, the starting spin trap DIPPMPO was completely characterized using GC-MS and its fragmentation pathway was studied in detail. Then, DIPPMPO was used to trap an oxygen-centered free radical (the hydroxyl radical • OH) and two carbon-centered free radicals (methyl • CH 3 and 1-phenyl-ethanol-1-yl • CCH 3 (OH)Ph radicals). The 31 P NMR signals were thus assigned and the structures of adducts were studied and confirmed by mass spectrometry. Overall, the fragmentation pathways of the radical adducts proceed mainly via the loss of the diisopropyloxy(oxido)phosphoranyl radical. For the specific case of trapping•OH radicals, it is possible to visualize the rearrangement of the nitroxide radical adduct to its nitrone form as invoked in the literature. This spin trapping technique, coupled with 31 P NMR and MS, provides a tool for the identification of short-lived and low molecular weight free radicals present in a variety of processes.

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Section: Carbon-centered Radicalscontrasting

confidence: 91%

Section: Europeanmentioning

confidence: 94%

Section: Europeanmentioning

confidence: 99%

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Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance

Zoia

Argyropoulos

2010

Eur J Mass Spectrom (Chichester)

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“…The shifts of the 31 P atom of the different species emerging from various reactions between DIPPMPO and carbon-centred radical species are well documented in the archival literature [14,17,18]. Much less is known, however, concerning the products that emerge from radical recombination reactions between DIPPMPO and nitrogen-centred radicals, that occur in, e.g., commercially available ammonia-based alkaline bleaching systems.…”

Section: Introductionmentioning

confidence: 99%

“…A well-studied spin trap system is the 5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO)/ 31 P NMR system; this system is well-known for the analysis of oxygen centred radicals [16,17].…”

Section: Introductionmentioning

confidence: 99%

Identification and quantification of radical species by 31P NMR-based spin trapping — A case study: NH4OH/H2O2-based hair bleaching

Crestini

Marsh

Bianchetti

et al. 2015

Microchemical Journal

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The 31 P NMR-spectroscopy-based spin trap technique involving 5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO) was used to achieve quantitative analyses of the radical species that are generated in different bleaching solutions. These solutions comprised a mixture of an ammonium salt and hydrogen peroxide. This spin trap-based approach was also applied, with modifications, to the study of bleaching systems of human hair. The obtained results clearly revealed the subtle differences in both the nature and the amounts of the radical species generated in different bleaching solutions, and when allowed to react on hair samples. Generally, the main species involved in the oxidation processes were superoxide and amino radicals. Their amounts, however, showed a significant variation upon the kind of bleaching system and nature of the hair, i.e., virgin or dyed hair.

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Pyrrole‐Assisted and Easy Oxidation of Cyclic α‐Amino Acid‐ Derived Diketopiperazines under Mild Conditions

et al. 2011

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A new procedure for the aerobic oxidation of a-amino acids acylated by pyrrole-carboxylic acid with triplet dioxygen is introduced. The reaction is general for a variety of pyrrole-amino acid derivatives and represents a very practical and controllable method for the selective preparation of a-hydroperoxy-or a-hydroxy-a-amino acid diketopiperazines with molecular dioxygen. Furthermore, the non-catalyzed direct oxidation of amino acid derivatives at the a-position with molecular dioxygen represents a fundamental question.

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Quantitative 31P NMR detection of oxygen-centered and carbon-centered radical species

Cited by 36 publications

References 23 publications

Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance

Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance

Identification and quantification of radical species by 31P NMR-based spin trapping — A case study: NH4OH/H2O2-based hair bleaching

Pyrrole‐Assisted and Easy Oxidation of Cyclic α‐Amino Acid‐ Derived Diketopiperazines under Mild Conditions

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Quantitative 31P NMR detection of oxygen-centered and carbon-centered radical species

Cited by 36 publications

References 23 publications

Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and 31P Nuclear Magnetic Resonance

Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and 31P Nuclear Magnetic Resonance

Identification and quantification of radical species by 31P NMR-based spin trapping — A case study: NH4OH/H2O2-based hair bleaching

Pyrrole‐Assisted and Easy Oxidation of Cyclic α‐Amino Acid‐ Derived Diketopiperazines under Mild Conditions

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Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance

Characterization of Free Radical Spin Adducts of 5-Diisopropyloxy-Phosphoryl-5-Methyl-1-Pyrroline-N-Oxide Using Mass Spectrometry and ³¹P Nuclear Magnetic Resonance