Base Peak Chromatogram (BPC)

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

Field desorption mass spectrometry of carboxylic acids: characteristic spectra and analysis of mixtures and impure samples

1978 ◽  
Vol 56 (10) ◽  
pp. 1372-1377 ◽  
Author(s):  
Gordon Walter Wooo ◽  
Emily Jane Oldenburg ◽  
Pui-Yan Lau ◽  
Donna Lee Wade
Keyword(s):  
Carboxylic Acids ◽  
Dicarboxylic Acids ◽  
Cross Product ◽  
Molecular Ions ◽  
Base Peak ◽  
Field Desorption ◽  
Technical Grade ◽  
Molecular Ion ◽  
Field Desorption Mass Spectrometry ◽  
Anode Temperature

Field desorption mass spectra were obtained for a variety of saturated and unsaturated carboxylic acids containing 12 or more carbons. At best anode temperature molecular ions were dominant and small peaks representing [M + 1]+, [2M + 1]+, [M − 17]+, and [Formula: see text] were present in several compounds. At higher temperatures several novel ions were found, including one corresponding to [2M + 1 – 18]+ which may represent anhydride formation. In a mixture of cis-5-eicosenoic and elaidic acids each molecular ion desorbed as expected but at higher temperatures the three possible anhydride ions appeared, with the cross product [M1 + M2 + 1 − H2O]+ as the base peak. Isomeric hydroxystearic acids (2-OH, 12-OH, 17-OH) gave predominantly ions in the molecular ion region with some differences in spectra which may relate to structure. Apparent polyester formation has been observed in 3-hydroxypropanoic acid where ions of the general formula [xM − (x − 1)H2O + H]+ with x = 2, 3, … 13 were found. Several other hydroxyacids show dimer formation and lactic acid has ions up to x = 5 in the above formula. Two of four technical grade dicarboxylic acids tested were seriously contaminated by sodium ions and gave useful spectra only after extraction by dibenzo-18-crown-6 ether. After this treatment both adipic and azelaic acid have [M + 1]+ as base peak, although adipic acid decarboxylates readily ([Formula: see text] = 74%) Other technical grade acids showed the presence of homologues and related structures as impurities.

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.

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.

Synthese, Schwingungs- und Massenspektren von Et2Sn(O2PR2)2 (R = Me, Ph); Kristallstruktur von Et2Sn(O2PPh2)2 / Synthesis, Vibrational Spectra and Mass Spectra of Et2Sn(O2PR2)2 (R = Me, Ph); Crystal Structure of Et2Sn(O2PPh2)2

1996 ◽  
Vol 51 (8) ◽  
pp. 1111-1116 ◽  
Author(s):  
Abdel-Fattah Shihada ◽  
Frank Weller
Keyword(s):  
Crystal Structure ◽  
Vibrational Spectra ◽  
Mass Spectra ◽  
Structure Refinement ◽  
Base Peak ◽  
Trans Position ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Environment ◽  
In Trans

Et2Sn(O2PPh2)2 has been synthesized by the reaction of (Et2ClSn)2O with Ph2POCl in toluene and by the treatment of (Et2ClSn)2O or Et2SnCl2 with HO2PPh2 in methanol. The reaction of Et2SnO with HO2PMe2 in toluene was used to prepare Et2Sn(O2PMe2)2. An X-ray diffraction study of Et2Sn(O2PPh2)2 (space group P1̅, Z = 1, a = 559,9( 1), b = 983,7(1), c = 1262,4(l)pm, α = 81,85( 1 )°, β = 79,79( 1)°, γ = 75,00(1)°; structure refinement with 2662 independent reflections, R = 0.055) shows that the structure is polymeric and the O2PPh2 ligands function as double bridges between the tin atoms leading to the formation of centrosymmetric Sn2O4P2 eight-membered rings. The ethyl groups are in trans-position in the resulting octahedral environment around tin. The I. R. and Raman spectra of Et2Sn(O2PR2)2 (R = Ph, Me) have been discussed and assigned. The mass spectra of Et2Sn(O2PR2)2 show Sn(O2PR2)+ as the base peak.

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

Spectres de masse d'hydrazino-2 benzo- et naphtothiazoles et d'hydrazones des méthyl-3 benzo- et naphtothiazolinones-2

1975 ◽  
Vol 53 (23) ◽  
pp. 3677-3680 ◽  
Author(s):  
Jean-Claude Richer ◽  
Philippe Lapointe ◽  
Martine Beljean ◽  
Michel Pays
Keyword(s):  
Mass Spectrum ◽  
Mass Spectra ◽  
Base Peak ◽  
Molecular Ion ◽  
Ion Fragmentation ◽  
Fragment Ions ◽  
Sampling Probe ◽  
Electron Impact Mass ◽  
Impact Mass ◽  
Hydrazone Form

Electron impact mass spectra are reported for the hydrazones of 3-methyl-2-benzothiazolinone (1), of 4-, 5-, 6-, and 7-chloro-3-methylbenzo-2-thiazolinones (2, 3, 4, and 5) and of 3-methyl-naphtho[2,1-d]-2-thiazolinone (6), as well as for 2-hydrazinobenzothiazole (7), for 4-, 5-, 6-, and 7-chloro-2-hydrazinobenzothiazoles (8, 9, 10, and 11) and for 2-hydrazinonaphtho[2,1-d]thiazole (12). The results obtained in the two series are compared. The 2-hydrazone and 3-methyl-benzo-2-thiazolinone and its derivatives all form a base peak corresponding to the molecular ion; fragmentation proceeds mainly by successive losses of·NH2, HCN, HCN, and then CS. Initial losses of N2H2, NH·, and NH3 are minor fragmentation routes.In the case of 2-hydrazinobenzothiazole and its derivatives, the base peak is still that of the molecular ion; however, the relative proportions of the various fragment ions vary with the position of sampling probe inside the apparatus. Thus it is concluded that the observed mass spectrum is that of a mixture of the possible hydrazone-hydrazine tautomers. The principal fragmentations involve the initial loss of NH3 (leading to a stabilized ion), of NH2· (probably from the hydrazone form), and of N2H2.(Journal Translation)

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.

scholarly journals Microwave-Assisted Synthesis of Para-Nitrophenol Using Calcium Nitrate

2021 ◽  
Vol 37 (1) ◽  
pp. 243-246
Author(s):  
Ivy Joyce Arenas Buan ◽  
Dyanne Jane Cid Duldulao
Keyword(s):  
Phenyl Ring ◽  
Calcium Nitrate ◽  
High Yield ◽  
Microwave Assisted Synthesis ◽  
Vibration Modes ◽  
Base Peak ◽  
Environmental Threats ◽  
Microwave Assisted ◽  
Environmentally Safe ◽  
Microwave Assisted Method

Conventional process of nitrating phenolic compounds involves the use of excess corrosive reagents that impose environmental threats. Rapid and environmentally friendly microwave-assisted nitration of phenol has been employed to limit the use of corrosive nitric acid and sulfuric acid. In this study, phenol is reacted to calcium nitrate and acetic acid, which served as nitrating agents. The solution is irradiated under microwave to complete the nitration process. This microwave-assisted- synthesis is a rate- enhanced process that showed complete nitration in a short reaction time of 1 min with a high yield of 89%. Bands of phenyl ring, OH, CO, and nitro groups observed in the FTIR spectra correspond to the vibration modes of para-nitrophenol. GCMS analysis showed a retention time of 7 min for the product with 139m/z base peak with matches that confirms the synthesis of para- nitrophenol. This microwave-assisted method can be employed as an efficient, environmentally safe, and rapid alternative nitration method for the synthesis of para-nitrophenol.

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