scholarly journals Mass Peak Profiling from Selected-Ion Recording Data as a Tool for Regulatory Analyses

1999 ◽  
Vol 82 (6) ◽  
pp. 1443-1457 ◽  
Author(s):  
Andrew H Grange ◽  
G Wayne Sovocool
Keyword(s):  
High Resolution Mass Spectrometry ◽  
High Mass ◽  
Generation Model ◽  
Mass Peak ◽  
Exact Mass ◽  
Temporal Separation ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Elemental Compositions ◽  
Fragment Ions

Abstract Identification of compounds in mixtures of environmental contaminants or synthetic products is essential for regulatory analyses. Exact masses of ions determined by high resolution mass spectrometry provide unique elemental compositions only for low-mass ions (<150 Da). Using mass peak profiling from selected-ion recording data (MPPSIRD) to acquire additional mass spectral data and a profile generation model (PGM) for automated interpretation of the data, provides elemental compositions for ions with m/z up to 600, based on incontestable properties of atoms, their exact masses, isotopic abundances, and valences. In this study, MPPSIRD and a PGM were used to identify intended and unintended products resulting from attempted syntheses of 2 thermolabile, nonionic, phosphorothioate compounds. The products were volatilized from a probe inserted into a VG70-250SE double-focusing mass spectrometer. High mass resolution substituted separation in the mass domain for the temporal separation of most components provided by chromatographic techniques. MPPSIRD and the PGM identified the correct composition for M+• by rejecting all other compositions that were possible within the error limits of the exact mass determinations for M+• MPPSIRD was used with 10 000-24 000 resolution to determine exact masses of ions prominent in mass spectra and to isolate signals from different ions with the same nominal mass. Superposition of volatilization peaks of ions and linked scans (constant magnetic field to electrostatic sector voltage ratio) correlated fragment ions with the molecular ion. The PGM determined the compositions of fragment ions, using the number of atoms of each element in the molecular ion as limits. Fragmentation schemes based on these ions and the tables of exact masses and relative abundances provided a preponderance of evidence for the product identities.

Mass spectral investigations on selenium compounds. II. The behaviour of meta-and para-substituted benzeneseleninic acids and of meta-nitrophenyl selenocyanate under electron impact

1982 ◽  
Vol 35 (7) ◽  
pp. 1365 ◽  
Author(s):  
A Benedetti ◽  
C Preti ◽  
L Tassi ◽  
G Tosi
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
Electron Impact ◽  
Molecular Ions ◽  
Selenium Compounds ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Low Intensity ◽  
Fragment Ions

Substituted benzeneseleninic acids of the type XC6H4SeO2H (X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO2, p-NO2) have been investigated by mass spectrometry. The fragmentation modes and the fragment ions are discussed and compared with those obtained from the mass spectrum of m-nitro-phenyl selenocyanate, O2NC6H4SeCN. Generally, as regards the acids, besides very weak peaks due to the molecular ions, a number of peaks at higher mass numbers and of greater intensity is observed; these peaks are in multiplets typical of the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC6H4SeSeC6H4X. m-Nitrophenyl selenocyanate shows an intense molecular ion peak and the relative fragmentation, while the peak due to the diselenide is of very low intensity.

Mass Spectral Studies of Binuclear Metal Complexes: Copper(I) Carboxylates

1973 ◽  
Vol 51 (17) ◽  
pp. 2999-3005 ◽  
Author(s):  
Denis C. K. Lin ◽  
John B. Westmore
Keyword(s):  
Fragmentation Pathway ◽  
Spectral Studies ◽  
Aryl Group ◽  
Decomposition Products ◽  
Fragmentation Pathways ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Fragment Ions ◽  
Binuclear Metal ◽  
And Migration

The thermal decomposition of twenty-five cupric carboxylates was studied by mass spectrometry. In eleven cases volatile cuprous carboxylates (many of which have not been previously reported) were detected amongst the decomposition products. The cuprous carboxylates from acetic, propionic, n-butyric, isobutyric, difluoroacetic, trifluoroacetic, benzoic, p-fluorobenzoic, p-chlorobenzoic, o-chlorobenzoic, and pentafluorobenzoic acids were all found to be dimeric in the vapor phase. Two basically different fragmentation pathways can be proposed depending upon whether the copper salt is formed from an alkyl- or aryl-carboxylic acid. For the former, the spectra are dominated by even-electron fragment ions formed by initial loss of RCO2•from the molecular ion. For the latter, a parallel fragmentation pathway initiated by loss of CO2 from the molecular ion and migration of the aryl group to the metal is also present.

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

1970 ◽  
Vol 48 (9) ◽  
pp. 1362-1370 ◽  
Author(s):  
C. Reichert ◽  
G. M. Bancroft ◽  
J. B. Westmore
Keyword(s):  
Mass Spectra ◽  
Molecular Ions ◽  
Metal Chelates ◽  
Spectral Studies ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Fragment Ions ◽  
D Orbitals

The mass spectra of the hexafluoroacetylacetonates (hfacac) and trifluoroacetylacetonates (tfacac) of Al(III), Cr(III), Fe(III), Fe(II), Cu(II), and Zn(II) are reported. The main features of the spectra are discussed. Compared with the spectra of the acetylacetonates (acac), substitution of CF3 for CH3 in these complexes leads to more extensive fragmentation of the molecular ions. For example, ions corresponding to loss of •CF3 radicals are more abundant than those corresponding to loss of •CH3 radicals. The appearance potentials (a.p.'s) of the molecular ions and, where possible, of fragment ions formed from the molecular ion by loss of •CF3, •CH3, or ligand radicals are reported. The a.p.'s of the molecular ions are more sensitive to the nature of the ligand than to the metal. Thus, for the metal chelates studied here the a.p.'s of the molecular ions from ML2 and ML3 (L stands for ligand) were 9.95 ± 0.25 V for L = hfacac, 9.05 ± 0.35 V for L = tfacac, and 8.3 ± 0.35 V for L = acac. The energy required to dissociate a •CF3 or •CH3 radical from the molecular ion is sensitive to the nature and valency of the metal M, being low (relatively) for Al(III) and Fe(III), and high (relatively) for Cr(III) (inferred) and Fe(II). This variation is discussed in terms of the effect of substituent, and of interaction of metal d orbitals with the ligands.

Determination of Elemental Compositions from Mass Peak Profiles of the Molecular Ion (M) and the M + 1 and M + 2 Ions

1996 ◽  
Vol 68 (3) ◽  
pp. 553-560 ◽  
Author(s):  
Andrew H. Grange ◽  
Joseph R. Donnelly ◽  
G. Wayne Sovocool ◽  
William C. Brumley
Keyword(s):  
Mass Peak ◽  
Molecular Ion ◽  
Elemental Compositions

scholarly journals Reaktive E=C(p–p)π Systeme, XXXIV Addition von Alkoholen oder primären Aminen an Phosphaalkene F3CP=C(F)OR. Neue Trifluormethylphosphane und -phosphaalkene/Reactive E = C( p – p ) π-Systems, XXXIV Addition of Alcohols or Primary Amines to Phosphaalkenes F3CP= C(F)OR . Novel Trifluoromethylphosphanes and Phosphaalkenes

1993 ◽  
Vol 48 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Gudrun Lange
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Molar Ratio ◽  
Primary Amines ◽  
The Novel ◽  
Experimental Conditions ◽  
Pull System ◽  
Fragment Ions ◽  
New Compounds ◽  
C Nmr

The course of the reactions o f fluorophosphaalkenes F3CP = C (F)OR [R = Me (1), Et (2)] with methanol or ethanol strongly depends on the experimental conditions. Thus at 70 °C a mixture of the 2-phosphapropionic acid ester F3CP (H )CO2R [R = Me (3), Et (4)] and trifluoromethylphosphane H2PCF3 is formed [molar ratio: 3 or 4 /H2 CF3 ≈1/1]. If the precursors F3CP (H )CO2R [R = Me (3), Et) are used as starting materials, the reaction with ROH under the same conditions affords 3 and 4, respectively, (90 to 95% yield) with only traces of H2PCF 3. In the presence o f iPr2NH these precursors react with R′OH to give the novel trifluoromethylphosphaalkenes F3CP = C (OR )OR [R /R′: Me/Me (6); E t/E t (7); Me/Et (8)]. With Et2NH , 3 undergoes an addition/elimination process yielding the interesting push/pull system Et2N(F)C = P-CO2Me (5). 1 and 2 react with primary amines R′NH2 (R′= tBu, Me) with stereoselective formation of the fairly labile phosphaalkenes F3CP = C(OR)NHR′ [R /R′: Me/tBu (9), Et/tBu(10), Me/Me (11)] with trans-positions for CF3 and NHR′.The new compounds 3 -11 were characterized by spectroscopic investigations (1H , 19F, 31P, 13C NMR ; IR, MS) and determination of M+ or typical fragment ions [M+ -OR ] by high resolution mass spectrometry.

scholarly journals The structure of novel C35 pentacyclic terpenes from Acetobacter xylinum

1973 ◽  
Vol 135 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Hans J. Förster ◽  
Klaus Biemann ◽  
W. Geoffrey Haigh ◽  
Neil H. Tattrie ◽  
J. Ross Colvin
Keyword(s):  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Carbon Chain ◽  
Acetobacter Xylinum ◽  
Mass Spectrometric ◽  
Hydroxyl Groups ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
High Resolution Mass ◽  
Resolution Mass

A novel C35 terpene and its monounsaturated analogue were isolated from cultures of Acetobacter xylinum, together with traces of their C36 homologues. These substances were found to be hopane derivatives substituted by a five-carbon chain bearing four vicinal hydroxyl groups. For the parent hydrocarbon the term bacteriohopane is proposed. The elucidation of the structures utilized high-resolution mass spectrometry of the terpenes, degradation to C32 hydrocarbons and detailed mass-spectrometric comparison of these with C32 hydrocarbons synthesized from known pentacyclic triterpenes. High-resolution mass-spectral data of the terpenes are presented. N.m.r. data are in agreement with the proposed structures, which are further supported by the isolation from the same organism of 22-hydroxyhopane and derivative hopene(s).

Differentiation of the Isomeric o-(m- and p-) Nitro-(Chloro- and Bromo-)Benzyl-2,4-(and 2,1-) Disubstituted 2-Thiocytosinium Halides by Electron Impact Ionisation and Fast Atom Bombardment Mass Spectrometry

2009 ◽  
Vol 15 (4) ◽  
pp. 497-506 ◽  
Author(s):  
Tomasz Pospieszny ◽  
Elżbieta Wyrzykiewicz
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Collision Induced Dissociation ◽  
Mass Measurements ◽  
Fragmentation Pathways ◽  
Mass Spectral ◽  
Fragment Ions ◽  
Accurate Mass Measurements ◽  
Impact Ionisation

Electron ionisation (EI) and fast atom bombardment (FAB) mass spectral fragmentations of nine 2,4-(and 2,1-) disubstituted o-( m- and p-)nitro-(chloro- and bromo-)-2-thiocytosinium halides are investigated. Fragmentation pathways, whose elucidation is assisted by accurate mass measurements and metastable transitions [EI-mass spectrometry (MS)], as well as FAB/collision-induced dissociation (CID) mass spectra measurements are discussed. The correlations between the abundances of the (C11H10N4SO2)+1–3; (C11H10N3SCl)+4–6 and (C11H10N3SBr)+7–9 ions and the selected fragment ions (EI-MS), as well as (C18H16N5SO4)+1–3; (C18H16N3SCl2)+4–6 and (C18H16N3SBr2) + 7–9 ions and the selected ions (C7H6NO2)+1–3; (C7H6Cl)+ 4–6; (C7H6Br)+ 7–9 (FAB-MS) are discussed. The data obtained can be used for distinguishing isomers.

scholarly journals Mass spectrometry analysis of polychlorinated biphenyls: Chemical ionization and selected ion chemical ionization using methane as a reagent gas

2000 ◽  
Vol 65 (5-6) ◽  
pp. 431-438 ◽  
Author(s):  
Tatjana Vasiljevic ◽  
Mila Lausevic ◽  
Raymond March
Keyword(s):  
Quantitative Analysis ◽  
Polychlorinated Biphenyls ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Quadrupole Ion Trap ◽  
Mass Spectrometry Analysis ◽  
Fragmentation Pattern ◽  
Gas Chromatograph ◽  
Molecular Ion ◽  
Fragment Ions

In the present paper a quadrupole ion trap mass spectrometer, coupled with a gas chromatograph, was used to compare the electron impact ionization (EI) and chemical ionization (Cl) technique, in terms of their selectivity in polychlorinated biphenyls (PCBs) quantitative analysis. The experiments were carried out with a modified Varian SATURN III quadrupole ion-storage mass spectrometer equipped with Varian waveform generator, coupled with a gas chromatograph with DB-5 capillary column. The disadvantage of using EI in the analysis of PCBs congeners is the extensive fragmentation of the molecular ion. The main fragmentation pattern recorded in the EI mass spectra of PCBs was the loss of a chlorine atom from the molecular ion. Therefore the fragment-ion signal overlapped with the molecular-ion cluster of lower mass congener. The fragmentation reactions of PCBs are suppressed if methane is used as a reagent gas for chemical ionization, but fragment ions are also present in the spectrum as an obstruction for quantitative analysis. The most selective method for PCBs quantitative analysis appears to be Cl with mass-selected C2H5 + ions from methane, which results in a mass spectrum with a negligible amount of fragment ions.

scholarly journals Electron Impact Ionization Mass Spectra of 3-Amino 6-Chloro2-methyl Quinazolin-4-(3H)-one Derivative

2021 ◽  
pp. 1-5
Author(s):  
Osarumwense Peter Osarodion ◽  
◽  
Omotade Treasure Ejodamen ◽  
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Impact Ionization ◽  
Cyclic Compound ◽  
Electron Impact Ionization ◽  
Ionization Mass ◽  
Fragmentation Pattern ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Characteristic Fragmentation

Looking at the previous studies on quinazolinones derivatives, only limited information’s are available on their mass spectral along with the preparation of novel quinazolin-4-(3H)-one derivatives The condensation of Methyl-2-amino-4-Chlorobenzoate with acetic anhydride yielded the cyclic compound 2-methyl 7-Chloro-1, 3-benzo-oxazine-4-one (1) which further produce 3-Amino-2-Methyl 7-Chloro quinazolin-4(3H)-ones (2) via the reaction with hydrazine hydrate. The compounds synthesized were unequivocally confirmed by means of Infrared, Nuclear Magnetic Resonance (1H and 13C), Gas Chromatography-Mass spectrophotometry and Elemental analysis. Discussion: The molecular ion of m/z 235 fragments to give m/z 220 by loss of –NH group. The ion of m/z 220 was broken to give m/z 206 by losing CH2 group and fragment to m/z 177 by loss of HCO. This fragmented to m/z 162 by loss of –CH3 group and then m/z 136 by loss of CN group. The loss of O gave m/z 120 which fragment to give m/z 93 by loss of –HCN and finally gave m/z 65 by loss of CO group. Conclusion: The electron impact ionization mass spectra of compound 2show a weak molecular ion peak and a base peak of m/z 235resulting from a cleavage fragmentation. Compound 2 give a characteristic fragmentation pattern. From the study of the mass spectra of compound 2, it was found that the molecular ion had fragmented to the m/z 220. The final fragmentation led to ion of m/z 93 and ion of mass m/z 65, respectively

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