Mass Spectrometric Studies on Organic Selenium-Oxygen Compounds. 1. Mass Spectra of Methyl p-Chlorobenzene Selenonate and Methyl p-Bromobenzene Selenonate.

The high-resolution mass spectra of benzo[b]thiophen, some alkyl and aryl derivatives, and the sulphone and 2,3-dihydrosulphone have been obtained; compositions of all significant ions in the spectra have been determined. Fragmentations of the unoxidized compounds are dominated by losses of C2H2 and CS units, while the sulphones undergo initial isomerization to cyclic sulphinates followed by expulsion of SO and fragments containing a C-O bond. Structures have been suggested for most of the ions observed.

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Gas-Liquid Chromatographic-Mass Spectrometric Confirmation of Endosulfan and Endosulfan Sulfate in Apples and Carrots

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/64.5.1208 ◽

1981 ◽

Vol 64 (5) ◽

pp. 1208-1210

Author(s):

Perry S Wilkes

Keyword(s):

Mass Spectra ◽

Chemical Ionization ◽

Mass Range ◽

Mass Spectrometric ◽

Chromatographic Retention ◽

Gas Liquid Chromatography ◽

Endosulfan Sulfate ◽

Gasliquid Chromatography ◽

Liquid Chromatographic ◽

Chromatographic Mass

Abstract A gas-liquid chromatography-mass spectrometric (GLC-MS) procedure is described for the confirmation of endosulfan I, endosulfan II, and endosulfan sulfate in apples and carrots. After extraction, cleanup, and determination by electron capture gasliquid chromatography using current AOAC methodology, residues are confirmed by GLC-MS. The chemical ionization (CI) mode is used with methane as a reagent gas. Each residue is confirmed by a scan of only 4 regions of its mass spectrum rather than the full mass range. The 4 mass regions for the 2 endosulfan isomers are 274-280, 340-346, 368-374, and 404-412 atomic mass units (amu). For endosulfan sulfate, the mass regions are 286-294, 322-330, 384-392, and 420-428 amu. Four ions and their chlorine isotopic distributions are detected for each compound by this scanning technique. This method was developed by using carrots and apples to which had been added 0.1 ppm (50% of the current legal tolerance on carrots) of each of the 3 pesticides. The gas chromatographic retention times and the mass spectra of the 4 mass regions specified for the 3 pesticides were compared to those of reference standards injected under identical GLC-MS conditions and were used as the basis for confirming identity of the 3 compounds.

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Mass Spectrometric Behaviour of Carboxylated Polyethylene Glycols and Carboxylated Octylphenol Ethoxylates

European Journal of Mass Spectrometry ◽

10.1255/ejms.540 ◽

2003 ◽

Vol 9 (3) ◽

pp. 165-173 ◽

Cited By ~ 8

Author(s):

Magdalena Frańska ◽

Agnieszka Zgoła ◽

Joanna Rychłowska ◽

Andrzej Szymański ◽

Zenon Łukaszewski ◽

...

Keyword(s):

Mass Spectrometry ◽

Alkali Metal ◽

Mass Spectra ◽

Secondary Ion Mass Spectrometry ◽

Metal Cations ◽

Mass Spectrometric ◽

Polyethylene Glycols ◽

Alkali Metal Cations ◽

Secondary Ion

The mass spectrometric behaviour of mono- and di-carboxylated polyethylene glycols (PEGCs and CPEGCs) and carboxylated octylphenol ethoxylates (OPECs) is discussed. The tendency for ionisation (deprotonation, protonation and cationisation by alkali–metal cations) of carboxylated PEGs was compared with that of non-carboxylated analogues by using both secondary-ion mass spectrometry (SIMS) and electrospray ionisation (ESI). The fragmentation of the PEGCs and CPEGCs is discussed and also compared with their neutral analogues, PEGs. B/E linked-scan mass spectra were recorded, using secondary-ion mass spectrometry as a method for ion generation, for deprotonated and protonated molecules as well as for molecules cationised by alkali–metal cations. The fragmentation behaviour of PEGs is found to be different from that of CPEGCs, The presence of carboxyl groups may be confirmed not only by the determination of molecular weights of the ethoxylates studied, but also on the basis of the fragment ions formed. The metastable decomposition of the [OPEC-H]− ions proceeds through the cleavage of the bond between the octylphenol moiety and the ethoxylene chain and leads to the octylphenoxyl anions. It permits determination of the mass of the hydrophobic moiety of the studied carboxylated alkylphenol ethoxylate. ESI mass spectra recorded in the negative-ion mode were found to be more suitable than SI mass spectra for the determination of the average molecular weight of carboxylated ethoxylates.

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Unexpected cytosine–AuCl4− interaction under electrospray ionization mass spectrometry conditions—Formation of cytosine–Au(I) complexes

European Journal of Mass Spectrometry ◽

10.1177/1469066719893233 ◽

2019 ◽

Vol 26 (3) ◽

pp. 225-229

Author(s):

Magdalena Frańska ◽

Emilia Konował

Keyword(s):

Electrospray Ionization ◽

Gas Phase ◽

Mass Spectra ◽

Mass Spectrometric ◽

Negative Ion ◽

Ionization Mass ◽

Ionization Source ◽

Full Scan ◽

Negative Ion Mode ◽

Product Ion Spectra

The interaction of cytosine with AuCl4−, under electrospray ionization mass spectrometric conditions, is discussed. On the basis of respective full scan mass spectra and product ion spectra, obtained in positive and negative ion mode, it has been deduced that cytosine is very prone to form Au(I)-containing complexes. The complexes may be formed in the gas phase by decomposition of Au(III)-containing complexes and also in the electrospray ionization source as a result of the occurrence of redox process. It has also been found that the interaction of cytosine with Au+ is stronger than that with Cu+ or Ag+, although taking into account the electrostatic attraction, it is not expected.

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Comparison of Gas Chromatographic/Mass Spectrometric and Liquid Chromatographic/Mass Spectrometric Methods for Confirmation of Coumaphos and Its Oxygen Analog in Eggs and Milk

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/66.6.1358 ◽

1983 ◽

Vol 66 (6) ◽

pp. 1358-1364

Author(s):

Kevin D White ◽

Zhao Min ◽

William C Brumley ◽

Richard T Krause ◽

James A Sphon

Keyword(s):

Mass Spectra ◽

Chemical Ionization ◽

Negative Ions ◽

Mass Spectrometric ◽

Ionization Mass ◽

Organophosphate Insecticide ◽

Ion Detection ◽

Oxygen Analog ◽

Liquid Chromatographic ◽

Chromatographic Mass

Abstract A comparison of a liquid chromatographic (LC)/mass spectrometric (MS) procedure for confirming coumaphos, an organophosphate insecticide, and its oxygen analog in milk and eggs with a capillary gas chromatographic (GO/MS method is presented. For the confirmation of coumaphos and its oxygen analog, multiple ion detection of both positive and negative ions from the chemical ionization mass spectra was used. Samples of milk and eggs fortified with the 2 compounds at the 0.1,0.01, and 0.005 ppm levels were analyzed. The major finding is the relatively greater efficiency of the LC/MS interface compared with the GC/MS capillary injector.

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Massenspektrometrische Untersuchungen an Borchelaten der Pyridin- und Chinolin-Reihe und deren N-Oxiden / Mass Spectrometric Investigations on Boron Chelates of the Pyridine and Quinoline Type and their N-Oxides

Zeitschrift für Naturforschung B ◽

10.1515/znb-1973-7-810 ◽

1973 ◽

Vol 28 (7-8) ◽

pp. 440-445 ◽

Cited By ~ 11

Author(s):

Eberhard Hohaus ◽

Wolfgang Riepe

Keyword(s):

Carboxylic Acid ◽

Mass Spectra ◽

Membered Ring ◽

Mass Spectrometric ◽

Ring Closure ◽

Boron Chelates ◽

Boron Chelate

Mass spectra of chelate-6-rings (N-oxide-chelates) are similar to those of comparable chelate-5-rings after elimination of oxygen from the fragment ion (M-C6H5). It is assumed that the fragment ion [(M-C6H5)-O] exists as a five-membered ring.However, there are two exceptions which are: The diphenyl boron chelate of pyridine-2-carboxylic acid anilide N-oxide with O-B-O-coordination and the difluorine boron chelate of 8-hydroxyquinoline N-oxide. The stable fragment OBX (X = C6H5F) is eliminated directly from the fragment ion (M-X). It is assumed the ring closure in [(M-X)-O] obviously is less favoured. The preparation of both 5-ring-chelates using the components is impossible, too.

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