1,720,989 research outputs found
Mass spectrometric study of 5,6- and 5,7-dihydroxytryptamines and their biological precursors.
No full text[C2O2](+center dot) ions of unusual structure
No full textThe structure of the C2O2+· ion, obtained by electron impact ionization of C3O2, is reported. A double-focusing instrument was used to carry out metastable ion and collisional spectroscopic studies. Comparison of the data showed that a C2O2+· species structurally different from those originating from other precursors is obtained by ionization of C3O2. A four-membered ring is proposed as the possible structure of the C2O2+· ion
HYDROXYINDOLE INTERMEDIATES IN THE PROCESS OF MELANOGENESIS - A MASS-SPECTROMETRIC STUDY
No full text
Mass Spectrometry of Some Fluornated Alcohols
No full textThe 70 eV electron impact mass spectrometric behaviour of some fluorinated alcohols, i.e. 2-fluoroethanol, 2,2,2,-trifluoroethanol, 2,2,3,3-tetrafluoropropan-1-ol and 1,3-difluoropropan-2-ol, was studied in detail by means of mass-analysed ion kinetic energy spectrometry, deuterium-labelling experiments and comparison with unfluorinated analogues. Composite metastable peaks related to HF losses were rationalized by invoking the presence of two concurrent decomposition pathways, the first consisting in a 1,2-elimination and the second requiring the implication of hydroxyl hydrogen. This last process and other decomposition routes suggest the presence of H bridging between the hydroxyl oxygen atom and fluorine
Matrix Assisted Laser Desorption/Ionization capabilities in the study of non-enzymatic protein glycation.
No full textStructural investigation of the hydroxy-propynal molecular ion
No full textA formyl ketenyl platinum derivative, trans-μ1-(PCy3)2(H)Pt[C(CHO)CO] (where Cy represents a cyclohexyl group), when reacted with HCl, gives a C3H2O2 species among the reaction products. The structure was investigated mass spectrometrically by study of the reactions of metastable ions, and the information gained was combined with data from theoretical calculations to rationalize the structure of the C3H2O2 molecule
ON THE GAS-PHASE REACTION OF C3O2+CENTER-DOT WITH C3O2
No full textThe gas-phase, ion molecule reaction between C3O2+ and C3O2 has been studied by both double-focusing and ion trap mass spectrometry, rationalized by the formation of a dimeric, odd electron cation [C6O4](+.) which decomposes extensively through sequential CO losses giving rise to [C5O3](+.) and [C4O2](+.) ions. The thermodynamics of this process have been investigated by means of ab initio calculation performed on the above species using different basis sets (STO-3G, 3-21G and 6-31G*)
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