Identification of Rubber Polymers by Mass Spectrometry

1963 ◽  
Vol 36 (3) ◽  
pp. 794-798
Author(s):  
J. K. Phillips
Keyword(s):  
Mass Spectrometry ◽  
High Temperature ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Analytical Procedure ◽  
Rubber Compound ◽  
Quantitative Analyses ◽  
The Common ◽  
Textile Polymers ◽  
Qualitative Analyses

Abstract The identity of an elastomer or elastomers in a rubber compound can be determined within a few minutes by the use of a new analytical procedure described in this article. It involves high temperature pyrolysis for two seconds, in vacuo, with an arc imaging furnace and subsequent analysis of the gaseous pyrolyzate with a mass spectrometer. Numerical values derived from the mass spectra of standards permit semi-quantitative analyses of some mixtures of elastomers in cured products. Qualitative analyses have also been made on most of the common textile polymers and a small number of miscellaneous polymers.

39 LIPID FINGERPRINTING OF INDIVIDUAL BOVINE BLASTOCYSTS BY DESORPTION IONIZATION ELECTROSPRAY MASS SPECTROMETRY

2012 ◽  
Vol 24 (1) ◽  
pp. 132 ◽  
Author(s):  
C. R. Ferreira ◽  
L. S. Eberlin ◽  
J. E. Hallett ◽  
R. G. Cooks
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Mass Spectrometer ◽  
Lipid Composition ◽  
Mass Spectra ◽  
Ms Analysis ◽  
Desi Ms ◽  
Complex Lipids

Mass spectrometry (MS) allows the detection and structural characterisation of intact molecules such as fatty acids and complex lipids. Desorption electrospray ionization (DESI) is an ambient ionization technique used for MS analysis and profiling and imaging of drugs, metabolites and lipids directly from biological samples with no sample preparation. With the recent introduction of morphologically friendly DESI-MS solvent systems, it is also possible to acquire DESI-MS data non-destructively. Due to the extractive nature of these solvent combinations, enough ion intensity can be generated to chemically profile samples of microscopic dimensions. The objective of this work was to perform chemical profiling on intact bovine blastocysts by DESI-MS, focusing on lipid distributions. Blastocysts produced in vitro were washed 3 times in PBS + 0.1% polyvinyl alcohol to remove lipids present in the culture medium, were placed in PBS/methanol 50% and stored under –20°C for 1 week. For DESI-MS analysis, the embryos were simply placed in glass slides and allowed to dry at room temperature. Mass spectra were acquired in the negative ion mode at the mass/charge range from m/z 150 to 1000, using as solvents a combination of 1:1 (vol/vol) ethanol:dimethylformamide (DMF) or acetonitrile:DMF. The mass spectrometer used was a LTQ linear ion trap mass spectrometer controlled by Xcalibur 2.0 software (Thermo Fisher Scientific, San Jose, CA, USA). The lipid species detected included deprotonated free fatty acids such as palmitic acid (m/z 255.2), stearic acid (m/z 283.2), arachidonic acid (m/z 311.2) and docosanoic acid (m/z 339.3). Free fatty acid dimers appear in the region from m/z 500 to 650 and complex lipids represented mainly by glycerophospholipid classes appear in the region from m/z 700 to 1000 and include phosphatidylinositols (PI 38:1; m/z 788.7), phosphatidylserines (PS 36:1, m/z 885.7) and also the chlorinated phosphatidylcholines (PC 36:1; m/z 794.7). After recording the mass spectra, embryos could still be observed in the glass slide with evident dehydration due to the action of the organic solvent. Since lipid composition of bovine embryos is closely related to cryosensitivity and due to the limited amount of analytes (each embryo is estimated to have a mass of 15 pg of total lipids) lipid analysis usually involves the pooling of individuals to have a large enough amount of analytes. Traditionally, gas chromatography is used for fatty acid residue analysis in oocytes and embryos pooled are submitted to lipid extraction and derivatization. Mass spectrometry by DESI, however, allows direct analysis of intact and single embryos and the profiling of not only free fatty acids but also complex lipids, represented mainly by 3 glycerophospholipid classes (PC, PI and PS). We envisage that DESI-MS will likely become a routine tool for the analysis of lipid composition in mammalian embryos and will contribute significantly to the development of culture systems that produce embryos with higher cryoresistance. Support from the Purdue University Center for Cancer Research Small Grants Program is gratefully acknowledged.

Thermal decomposition ractions of caledonite and their products

1986 ◽  
Vol 50 (357) ◽  
pp. 521-526 ◽  
Author(s):  
D. J. Morgan ◽  
S. St. J. Warne ◽  
S. B. Warrington ◽  
P. H. A. Nancarrow
Keyword(s):  
Mass Spectrometry ◽  
Phase Transition ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Decomposition Products ◽  
Lead Sulphate ◽  
Ion Fragmentation

AbstractThe thermal decomposition of caledonite has been examined by simultaneous differential thermal analysis, thermogravimetry and mass spectrometry. Structural H2O and CO2 are liberated endothermically between 300 and 400°C leaving a residue of lead sulphate, oxysulphate, and Cu(I) and Cu(II) oxides. A series of sharp endothermic peaks between 850 and 950°C correspond to phase transition and melting reactions of the PbO-PbSO4 mixture. The sulphate anion breaks down above 880 °C. Mass spectra of the gaseous decomposition products show SO2, SO, and O2, although SO is an artefact arising from ion fragmentation of the SO2 within the mass spectrometer. The residue at 1060 °C is composed predominantly of 2PbO · PbSO4 and Cu(I) and Cu(II) oxides.

OESTROGEN IN HUMAN PREGNANCY FAECES

1976 ◽  
Vol 83 (2) ◽  
pp. 410-419 ◽  
Author(s):  
Herman Adlercreutz ◽  
Finian Martin
Keyword(s):  
Mass Spectrometry ◽  
Biologically Active ◽  
Gas Chromatography Mass Spectrometry ◽  
Mass Fragmentography ◽  
Marked Contrast ◽  
Bacterial Enzyme ◽  
Quantitative Analyses ◽  
Normal Women ◽  
Qualitative Analyses ◽  
In Pregnancy

ABSTRACT The oestrogen content of two 24 h pools of pregnancy faeces, obtained from 2 normal women in the 33rd–37th week og gestation, was studied. The qualitative analyses were made by gas chromatography - mass spectrometry and the quantitative analyses by mass fragmentography. The presence of the following oestrogens in pregnancy faeces was established: Oestriol, oestrone, oestradiol-17β, 16-epioestriol, 17-epioestriol, 16α-hydroxyoestrone, 16-oxo-oestradiol-17β, 15α-hydroxyoestrone and 15α-hydroxyoestradiol-17β. In addition, mass fragmentographic evidence was obtained for the presence of 16β-hydroxyoestrone, 2-methoxyoestrone and oestradiol-17α. The total oestrogen excretion determined in the two pools was 786 and 1300 μg per 24 h. Unconjugated oestrogens accounted for 97.8 and 98.6% of these amounts, respectively. Oestriol, oestradiol-17β, 15α-hydroxyoestradiol-17β, 16-epioestriol and oestrone, in that order, were quantitatively the most significant of the oestrogens determined. The remarkably high levels of oestradiol-17β found in faeces show, that in pregnancy, this mode of excretion is as important as urine for the elimination of this biologically active steroid. It is suggested that some of the oestradiol may have been formed through bacterial enzyme action from other oestrogens or neutral steroids. Only trace amounts of ring D α-ketolic oestrogens were found in faeces. This is in marked contrast to the considerable amounts of these steroids found in pregnancy bile and urine.

Determination by mass spectrometry of the structure of bisbenzoylacetoneethylenediimine and its metal chelates

1965 ◽  
Vol 18 (10) ◽  
pp. 1539 ◽  
Author(s):  
SHH Chaston ◽  
SE Livingstone ◽  
TN Lockyer ◽  
JS Shannon
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Metal Chelates ◽  
Methyl Groups ◽  
Rearrangement Reactions

The mass spectra of bisbenzoylacetoneethylenediimine (B) and its cobalt(II), nickel(II), and copper(II) complexes have been rationalized in terms of form (II) for B in which the imino nitrogens are attached to the same carbon atoms as the methyl groups and not to the same carbon atoms as the phenyl groups, as previously proposed in the literature. Compound B is thus NN'-ethylenebis(benzoylisopropylideneimine). Novel ion-rearrangement reactions and examples of changes in metal valency in the mass spectrometer are described.

Mass Spectrometry of Benzyne and Cyclopentadienylideneketene

2010 ◽  
Vol 63 (7) ◽  
pp. 1076 ◽  
Author(s):  
Thomas Monsandl ◽  
Graham Macfarlane ◽  
Robert Flammang ◽  
Curt Wentrup
Keyword(s):  
Mass Spectrometry ◽  
High Temperature ◽  
Mass Spectrometer ◽  
Temperature Regime ◽  
Time Scale ◽  
Ring Opening ◽  
Collisional Activation ◽  
High Temperature Regime ◽  
Line Mass ◽  
On Line

The formation of cyclopentadienylideneketene 2 and benzyne 1 in flash vacuum thermolysis reactions is investigated by on-line mass spectrometry. Compounds 13, 14, and 15 all afford ketene 2, which decomposes to benzyne and CO in the high-temperature regime. Cyclopentadienylideneketene 2 is stable on the microsecond time-scale of neutralization-reionization experiments. Collisional activation mass spectrometry of m/z 76 from 14, 15, and 5 indicates that the C6H4•+ ions most likely undergo ring opening in the mass spectrometer.

The Ion Kinetic Energy Spectra of Benzyl Fluoride and the Isomeric Fluorotoluenes

1974 ◽  
Vol 52 (6) ◽  
pp. 867-869 ◽  
Author(s):  
S. Safe ◽  
W. D. Jamieson ◽  
D. J. Embree
Keyword(s):  
Mass Spectrometry ◽  
Kinetic Energy ◽  
Mass Spectrometer ◽  
Aromatic Compounds ◽  
Mass Spectra ◽  
Energy Spectra ◽  
Model Compounds ◽  
Free Region ◽  
Field Free Region ◽  
Ion Kinetic Energy

One of the classical problems in mass spectrometry is the structure and formation of the C7H7+ and XC7H6+ ions which are generated in the mass spectra of alkylbenzenes and many other aromatic compounds. The intermediacy of both symmetrical tropylium ion structures and unsymmetrical benzyl ions has been postulated using a number of different approaches. We have investigated this problem using ion kinetic energy spectroscopy, a relatively new technique, with the isomeric fluorobenzenes and benzyl fluoride as model compounds. Our results indicated incomplete substituent (i.e. fluorine) scrambling in the first field-free region of the mass spectrometer and thus incomplete equilibration in the decomposing FC7H6+ ions and these conclusions are in contrast to results obtained using other techniques.

scholarly journals Analytical procedure for the determination of tetracyclines in medicated feedingstuffs by liquid chromatography-mass spectrometry

2016 ◽  
Vol 60 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Ewelina Patyra ◽  
Krzysztof Kwiatek
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Mass Spectrometer ◽  
Analytical Procedure ◽  
Liquid Chromatography Mass Spectrometry ◽  
Analytical Column ◽  
Mcilvaine Buffer ◽  
Chromatography Mass Spectrometry ◽  
Feed Samples

Abstract Introduction: The article presents a rapid and simple analytical procedure for determination of four tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in animal medicated feedingstuffs. Material and Methods: Two-gramme samples were extracted by a Na2EDTA-McIlvaine buffer (pH 4)/methanol mixtures (40/60, v/v). The determination was achieved by liquid chromatography using a Zorbax Eclipse XDB C18 analytical column with mass spectrometer detection (LC-MS). Results: Recoveries of the antibiotics from spiked feed samples ranged from 78.2% to 113.5%. The LOD and LOQ for tetracyclines in feeds ranged from 2.8 to 4.2 and from 4.3 to 5.7 mg/kg, respectively. Conclusion: The method was successfully validated and proved to be efficient, precise, and useful for quantification of tetracyclines in medicated feedingstuffs.

The challenge of detecting modifications on proteins

2020 ◽  
Vol 64 (1) ◽  
pp. 135-153 ◽  
Author(s):  
Lauren Elizabeth Smith ◽  
Adelina Rogowska-Wrzesinska
Keyword(s):  
Mass Spectrometry ◽  
Protein Function ◽  
Chemical Properties ◽  
Lysine Acetylation ◽  
Mass Determination ◽  
Post Translational Modifications ◽  
Site Specific ◽  
The Common

Abstract Post-translational modifications (PTMs) are integral to the regulation of protein function, characterising their role in this process is vital to understanding how cells work in both healthy and diseased states. Mass spectrometry (MS) facilitates the mass determination and sequencing of peptides, and thereby also the detection of site-specific PTMs. However, numerous challenges in this field continue to persist. The diverse chemical properties, low abundance, labile nature and instability of many PTMs, in combination with the more practical issues of compatibility with MS and bioinformatics challenges, contribute to the arduous nature of their analysis. In this review, we present an overview of the established MS-based approaches for analysing PTMs and the common complications associated with their investigation, including examples of specific challenges focusing on phosphorylation, lysine acetylation and redox modifications.

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