The Mass Spectra of Some Organophosphorus Pesticide Compounds

1966 ◽  
Vol 49 (5) ◽  
pp. 1027-1045
Author(s):  
Joseph N Damico
Keyword(s):  
Alkyl Group ◽  
Mass Spectra ◽  
Organophosphorus Pesticide ◽  
Ester Group ◽  
Base Peak ◽  
Mass Measurements ◽  
Model Compounds ◽  
Hydrogen Migration ◽  
Accurate Mass Measurements ◽  
Individual Parent

Abstract The mass spectra of 23 pentavalent organophosphorus pesticide esters were investigated. Rearrangements and fragmentation by simple cleavage are postulated from analogy with similar compounds, from the presence of chlorine atoms with their readily-recognizable isotopic distribution when applicable, from elemental compositions determined by accurate mass measurements, and, in a few cases, from model compounds. The compounds are divided into four groups: phosphorodithioates, phosphorothionates, phosphorothiolates, and phosphates. The base peaks are formed by rearrangements and simple cleavage. Rearrangement ions are formed by (I) hydrogen migration from the alkyl ester group to the thiophosphite-oxygen skeleton; (2) migration of hydrogen from the Z moiety (aryl or alkyl group) to the phosphorus-oxygen skeleton; (3) migration of hydrogen from the Z moiety to the thiophosphite-oxygen skeleton; (4) migration of hydrogen from the ester group bonded to phosphorus to the Z moiety; and (5) alkyl migration to the Z moiety. The base peak does not characterize the different groups or compounds within a group. However, beta-cleavage (relative to the Z moiety) producing relatively intense peaks (with the charge on the Z moiety) is characteristic of a given group. These data may be useful in identifying metabolites isolated from crops field sprayed with an individual parent organophosphorus pesticide.

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.

Mass spectral studies of some desaurins and related 3,5-bismethylene-1,2,4-trithiolanes

1968 ◽  
Vol 46 (3) ◽  
pp. 365-375 ◽  
Author(s):  
Peter Yates ◽  
Thomas R. Lynch ◽  
L. S. Weiler
Keyword(s):  
Carbonyl Group ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Spectral Studies ◽  
Mass Measurements ◽  
Metastable Peak ◽  
Fragmentation Pathways ◽  
Mass Spectral ◽  
Accurate Mass Measurements ◽  
Doubly Charged

The mass spectra of three desaurins and four related 3,5-bismethylene-1,2,4-trithiolanes have been interpreted with the aid of metastable peak assignments and accurate mass measurements. Strong molecular ion peaks are observed in the case of the aryl desaurins but not in that of their trithiolane counterparts. A variety of fragmentation pathways are postulated for the molecular ions, including cleavage on either side of a carbonyl group and elimination of a molecule of acylthioketene. In the case of the desaurins the latter process results in the formation of acylthioketene molecular ions, which could be distinguished from the doubly charged desaurin molecular ions. In the case of two of the trithiolanes, it is proposed that the ions resulting from loss of acylthioketene from the molecular ions undergo a novel type of McLafferty rearrangement and loss of carbon suboxysulfide to give aryl mercaptan molecular ions.

Some Aspects of the Mass Spectra of.N-Nitrosamines

1971 ◽  
Vol 49 (9) ◽  
pp. 1367-1371 ◽  
Author(s):  
J. W. ApSimon ◽  
J. D. Cooney
Keyword(s):  
Mass Spectra ◽  
Accurate Mass ◽  
Mass Measurements ◽  
Molecular Ion ◽  
Accurate Mass Measurements ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns

The mass spectra of seven cyclic N-nitrosamines were examined for characteristic fragmentation patterns. Accurate mass measurements on three of the compounds indicated that the M-17 and M-30 peaks resulted from molecular ion losses of •OH and •NO respectively. The loss of • OH was rationalized in terms of a McLafferty-type rearrangement.

Organophosphorus compounds. VII. Electron-impact fragmentations of esters of phosphonic acids

1966 ◽  
Vol 19 (7) ◽  
pp. 1187 ◽  
Author(s):  
JL Occolowitz ◽  
JM Swan
Keyword(s):  
Electron Impact ◽  
Phosphorus Atom ◽  
Mass Spectra ◽  
Organophosphorus Compounds ◽  
Ester Group ◽  
Base Peak ◽  
Phosphonic Acids ◽  
Hydrocarbon Group ◽  
Carbon Fragment ◽  
Hydro Carbon

The mass spectra of some dialkyl and diaryl esters of a variety of alkyl-, alkenyl-, alkynyl-, and aryl-phosphonic acids are discussed. The spectra are in many cases similar to those observed for simple dialkyl alkylphosphonates, but with some important differences depending on the nature of the hydrocarbon group attached directly to the phosphorus atom. Some unusual rearrangements are observed, involving migration of a hydro-carbon fragment from the ester group to the hydrocarbon moiety attached to phosphorus, with simultaneous expulsion of a phosphinyl radical. Thus diethyl vinylphosphonate gives an ion [C4H7]+; diethyl 2-phenylvinylphosphonate gives a base peak at m/e 131 due to PhCH=CHCHCH3; diphenyl 2-phenylvinylphosphonate gives an ion [C14H12O]+', and from this, an ion [C14H10]+ which can be formulated as the molecular ion of phenanthrene.

scholarly journals Contributions to the Interpretation of Mass Spectra of the TEOS Methoxy-Transesters. Linked Scans, Accurate Mass Measurements and M+1, M+2 Isotopic Effects

2020 ◽  
Vol 71 (8) ◽  
pp. 39-54
Author(s):  
Virgil Badescu
Keyword(s):  
Mass Spectra ◽  
Structural Formula ◽  
Molecular Ions ◽  
Accurate Mass ◽  
Mass Measurements ◽  
Electronic Impact ◽  
Accurate Mass Measurements ◽  
Fragmentation Reactions ◽  
Double Focusing ◽  
Isotopic Effects

The aim of this article is the study of the fragmentation reactions of the methoxy-transesters of tetraethoxysilane (TEOS), with structural formula (CH3O)x(C2H5O)ySi, initiated by electronic impact in the ionization chamber of a double focusing mass spectrometer. The initiation centers of fragmentation reactions for the neutral and ionized TEOS methoxy-transesters were established by quantum calculations of net atomic charges. The ions of the mass spectra of the TEOS methoxy-transesters were obtained experimentally by the B/E and B/E(1-E)1/2 linked scans. Thus, there can be written the fragmentation pathways for the primary events by B/E linked scan (cleavage of methoxy and ethoxy groups) and eliminations of neutral molecules (acetaldehyde, ethylene, formaldehyde, molecular hydrogen) by B/E(1-E)1/2 linked scan. Accurate mass measurements at high resolution (5000), double bond equivalent (DBE) for the molecular ions and fragmentation ions of the TEOS methoxy-transesters and M+1, M+2 isotopic effects were used to confirm their identification. The reaction pathways and accurate mass in mass spectrum of dimethoxydiethoxysilane (TR2M) are detailed.

Structure Revision of Protoaculeine B, a Posttranslationally Modified N-Terminal Residue in the Peptide Toxin Aculeine B

2020 ◽  
Author(s):  
Raku Irie ◽  
Kei Miyako ◽  
Satoko Matsunaga ◽  
Ryuichi Sakai ◽  
Masato Oikawa
Keyword(s):  
Mass Spectra ◽  
Chemical Reactivity ◽  
Model Compounds ◽  
Structural Revision ◽  
Structure Revision ◽  
Peptide Toxin ◽  
One Step ◽  
Marine Peptide ◽  
Synthetic Models ◽  
Long Chain

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

scholarly journals Fast atom bombardment mass spectra of the .BETA.-blocker nipradilol with nitrate ester group-tandem mass spectrometry (MS/MS) and B/E constant linked scanning.

1990 ◽  
Vol 38 (12) ◽  
pp. 3389-3394 ◽  
Author(s):  
Michiaki YONEDA ◽  
Kazuo TSUJIMOTO ◽  
Mamoru OHASHI ◽  
Masami SHIRATSUCHI ◽  
Yasushi OHKAWA ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Beta Blocker ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Ester Group ◽  
Tandem Mass ◽  
Nitrate Ester
Sign in / Sign up

Export Citation Format

Share Document