Intensity Relative to Base Peak (in Mass Spectrometry)

2016 ◽  
Author(s):  
Kermit K. Murray ◽  
Robert K. Boyd ◽  
Marcos N. Eberlin ◽  
G. John Langley ◽  
Liang Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Base Peak

Quantitative Confirmation of Dimethoate Residues in Wheat Plants by Single Ion Mass Spectrometry

1979 ◽  
Vol 62 (4) ◽  
pp. 782-785
Author(s):  
Young W Lee ◽  
Neil D Westcott
Keyword(s):  
Mass Spectrometry ◽  
Internal Standard ◽  
Wheat Plant ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Plant Sample ◽  
Minimum Detectable Concentration ◽  
Mass Spectrometric Method ◽  
Base Peak ◽  
Detectable Concentration

Abstract A gas chromatographic-single ion mass spectrometric method was developed for determining dimethoate residues in wheat plants. The base peak (m/e 87) of dimethoate was chosen as the single ion peak, and methyl stearate was used as an internal standard for this analysis. The minimum detectable concentration of dimethoate by this method was about 0.1 ppm for a 20 g wheat plant sample. The recoveries of dimethoate were about 89% at 0.13 ppm and >96% at 0.5-1 ppm.

Naphtho[1,8-bc]thiophens. II. Mass spectrometry

1968 ◽  
Vol 21 (1) ◽  
pp. 171 ◽  
Author(s):  
DG Hawthone ◽  
QN Porter
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Electron System ◽  
Complete Analysis ◽  
Base Peak ◽  
Aromatic System ◽  
Chemical Research ◽  
Fragment Ions ◽  
The Stability ◽  
Derivatives Of

II.* MASS SPECTROMETRY By D. G. HAWTHORN,E~$ and Q. N. PORTER^ [Manzlscript received March 6, 19671 The high-resolution mass spectra of some derivatives of naphtho[l,S-be]- thiophen have been analysed. The base peak in the spectra is usually the naphtho- [1,8-bclthienylium cation (mle 171) or one of its substitution products; this emphasizes the stability of this species. Structures are suggested for most of the other ions observed in the spectra. INTRODUUTION In Part I, which dealt with the synthesis of naphtho[l,8-bclthiophen derivatives, the mass spectra of the 2-methyl-2H- (I; R = CH,) and 2-phenyl-2H- (I; R = Ph) compounds were briefly described. It was suggested that in each case the cleavage shown gave the ion of mle 171, for which the naphthothienylium cation structure ac was proposed. (1) ac; m/e 171 In this paper we present a complete analysis of the spectra of these compounds, and of some related naphtho[l,8-bclthiophen derivatives. For reasons outlined in Part I of this series, it is not possible to write structures for fragment ions from aromatic and heteroaromatic molecules with the confidence with which this can be done for many less-aromatic systems. In writing ionic structures to formalize the observed spectra, the following principles have been used: (i) Where the formation of an odd-electron system is involved, the ion is, if possible, written as a radical cation derivable from an aromatic system. There is * Part I, Aust. J. Chem., 1966, 19, 1909. t Department of Organic Chemistry, University of Melbourne, Vic. 3052. $ Present Address: Division of Applied Mineralogy, CSIRO Chemical Research Labora- tories, Melbourne, Vic. 3001. Aust. J. Chem., 1968, 21, 171-83

scholarly journals ANALISIS, IDENTIFIKASI PRECURSOR DAN HASIL DEGRADASI SENYAWA SENJATA KIMIA MENGGUNAKAN TEKNIK GAS CHROMATOGRAPHY MASS SPECTROMETRY– ELECTRON IONISASI (GCMS-EI)

2014 ◽  
Vol 16 (1) ◽  
pp. 1-9
Author(s):  
Evita Boes
Keyword(s):  
Mass Spectrometry ◽  
Phosphonic Acid ◽  
Retention Time ◽  
Soil Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Identification System ◽  
Chemical Weapon ◽  
Base Peak ◽  
Mass Spectral ◽  
Chromatographic Mass

Telah dilakukan analisis, identifikasi precursor dan hasil degradasi senyawa senjata kimia  diethyl methylphosphonat (DEMP), methyl phosphonic acid (MPA) dalam sampel air dan  dimethyl methyl phosphonat (DMMP), ethyl phosphonic acid (EPA) dalam sampel tanah. Contoh yang dianalisa merupakan contoh senyawa tributilphosphat  (TBP)  40 ug/mL dan poliethilene glycol  56,24 ug/mL ditambahkan sebagai background dan sampel tanah kering yang berpasir. Identifikasi dilakukan dengan  metode  kromatografi gas spektrometri massa - elektron ionisani (GCMS-EI). Ekstraksi fasa organik  pada pH netral, sililasi dari fasa air yang diuapkan,  di mana triethylamine/methanol-sililasi dan  kation exchange-sililasi digunakan untuk ekstraksi senyawa - senyawa precursor dan hasil degradasi sebelum diinjeksikan ke GCMS. Dari hasil analisis diperoleh  waktu retensi  8,9 dan 10,97  menit  masing - masing untuk  diethyl methylphosphonat dan bis(trimethylsilyl) methylphosphonate dalam sampel air sedangkan dalam sampel tanah  6,62 dan 12,06 menit untuk dimethyl methylphosphonat  dan bis(trimethylsilyl) ethylphosphonate. Total Ion Chromatography (TIC) yang dihasilkan dari GCMS dievaluasi dengan menggunakan    Library Data Base NIST (National Institute of Standards and Technology), dan AMDIS (Automated Mass Spectral Deconvolution and Identification System). Spektrum yang dihasilkan memberikan nilai base peak pada m/z = 97  untuk  diethyl methylphosphonate , m/z = 225 untuk  bis(trimethylsilyl) methylphosphonate, m/z = 94 untukdimethyl methylphosphonate dan m/z = 239 untuk bis(trimethylsilyl) ethylphosphonate sedangkan  retention index (RI) yang dihitung digunakan untuk  mengonfirmasi masing-masing senyawa precursorKata kunci : precursor, degradsi senyawa senjata kimia, base peak , waktu retensi,  Total Ion KromatografiAnalysis, precursoridentification have been done and  degradation compoundsof chemical weapon diethyl methylphosphonat , methyl phosphonic acid in water matrices, dimethyl methylphosphonat and ethyl phosphonic acidin soil samples. Water used for extracting those  compounds was an example of simulation that contain tributilphosphat  (TBP)  40 ug/mL and poliethylene glycol  56,24 ug/mL which added as a background and  dry sandy soil samples. Identification was done  by using Gas Chromatographic Mass Spectrometry – Electron Ionization (GCMS-EI) method. Neutral organic extraction, evaporated water - silylation, triethylamine/methanol-silylation and cation exchanged-silylation were performed to extract the precursor’s compounds from the samples, before being analyzed by gas chromatography mass spectrometry .The result of the analysis by  Gas Chromatographic  Mass Spectrometry  method showed that the retention time (in min) was 8,9 and 10,97 for diethyl methylphosphonat and bis(trimethylsilyl) methylphosphonate in the water sample , while the retention time in soil sample was 6,62 and  12,06 for dimethyl methylphosphonat and bis(trimethylsilyl) ethylphosphonate . The result of Total Ion Chromatography (TIC) from GCMS was evaluated using NIST (National Institute of Standards and Technology) database library and AMDIS (Automated Mass Spectral Deconvolution and Identification System). The spectrum’s result gave the value of base peak, which are m/z = 97for diethyl methylphosphonat, m/z= 225 for bis(trimethylsilyl) methylphosphonate , m/z = 94 for dimethyl methylphosphonat and m/z = 239 for bis(trimethylsilyl) ethylphosphonate. On the other hand, the retention indice (RI) calculation was used to get the confirmation of each compounds of precursors. Key word : precursor, degradation of chemical weapon,  base peak, retention time, totalion chromatography.

Polymerization in situ Accompanying Field Desorption Mass Spectrometry

1975 ◽  
Vol 53 (22) ◽  
pp. 3500-3502 ◽  
Author(s):  
Gordon Walter Wood ◽  
Donna Lee Wade
Keyword(s):  
Mass Spectrometry ◽  
Water Loss ◽  
Condensation Polymerization ◽  
Base Peak ◽  
Field Desorption ◽  
Desorption Mass Spectrometry ◽  
Hydroxycarboxylic Acids ◽  
Field Desorption Mass Spectrometry

Field desorption mass spectrometry of hydroxycarboxylic acids results in ions corresponding to condensation polymerization with water loss. The phenomenon is particularly marked with 3-hydroxypropanoic acid where at high anode temperatures the base peak corresponds to 6M – 5H2O and ions up to 13M – 12H2O are observed.

Fast Atom Bombardment Mass Spectrometry of Arene-Chromium Complexes: Cr(η6-C6-Ph6)2, Cr{η6-PhPh[Cr(CO)3]}2 and Fe(η-C5H4-η6-PhCr(CO)3)n(η-C5H4Ph)2-n (N = 0-2)

1992 ◽  
Vol 45 (7) ◽  
pp. 1095 ◽  
Author(s):  
MI Bruce ◽  
NN Zaitseva
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Base Peak ◽  
Chromium Complexes ◽  
Ferrocene Derivatives

The fast atom bombardment mass spectra of several high molecular weight η- arene -chromium complexes have been measured and analysed. Interesting features include the observation of loss of C2Ph2 from [Cr(C6Ph6)2]+ to give [Cr(C10Ph10)]+ as the base peak, which appears to be derived from pentaphenylcyclopentadiene; the ready loss of Cr(CO)3 moieties from complexes containing this group; and the formation of ions containing CrFe groups in the spectra of the ferrocene derivatives.

Copper-Induced Oligomerization of Peptides: A Model Study

2007 ◽  
Vol 13 (5) ◽  
pp. 331-337 ◽  
Author(s):  
Gitta Schlosser ◽  
Raluca Stefanescu ◽  
Michael Przybylski ◽  
Manuela Murariu ◽  
Ferenc Hudecz ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Metal Ion ◽  
Ion Binding ◽  
Ionization Mass ◽  
Copper Binding ◽  
Base Peak ◽  
Metal Ion Binding ◽  
Model Study ◽  
Alkaline Conditions ◽  
Singly Charged

In this work, copper-binding of the tetraglycine peptide (Gly–Gly–Gly–Gly) was studied by electrospray ionization mass spectrometry. Experiments were performed under alkaline conditions, in the presence of ethanolamine (pH 10.95). We observed that the presence of copper(II) ions induces the aggregation of the peptide and the formation of copper-bound complexes with higher molecular mass is favored, such as the oligomer complexes [3M + 2Cu – 3H]+ and [4M + 3Cu – 5H]+. At 1:1 peptide–copper(II) ion ratio, the singly charged [3M + 2Cu – 3H]+ oligomer complex is the base peak in the mass spectrum. Metal ion-induced oligomerization of neurotoxic peptides is well known in the literature; however, there are very few examples in which such oligomerization was directly observed by mass spectrometry. Our results show that application of short peptides can be useful to study the mechanism of metal ion binding and metal ion-induced oligomerization of peptides.

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