Laser mass spectrometry of polyglycols: comparison with other mass spectral techniques

1985 ◽  
Vol 57 (11) ◽  
pp. 2041-2046 ◽  
Author(s):  
David E. Mattern ◽  
David M. Hercules
Keyword(s):  
Mass Spectrometry ◽  
Laser Mass Spectrometry ◽  
Spectral Techniques ◽  
Mass Spectral

scholarly journals Mass Spectrometry-Based Characterization of New Spirolides from Alexandrium ostenfeldii (Dinophyceae)

Marine Drugs ◽  
2020 ◽  
Vol 18 (10) ◽  
pp. 505
Author(s):  
Joyce A. Nieva ◽  
Jan Tebben ◽  
Urban Tillmann ◽  
Sylke Wohlrab ◽  
Bernd Krock
Keyword(s):  
Mass Spectrometry ◽  
High Resolution Mass Spectrometry ◽  
Molecular Ions ◽  
Ring System ◽  
The Other ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Alexandrium Ostenfeldii ◽  
Different Strains

Spirolides belong to a group of marine phycotoxins produced by the marine planktonic dinophyte Alexandrium ostenfeldii. Composed of an imine moiety and a spiroketal ring system within a macrocylcle, spirolides are highly diverse with toxin types that vary among different strains. This study aims to characterize the spirolides from clonal A. ostenfeldii strains collected from The Netherlands, Greenland and Norway by mass spectral techniques. The structural characterization of unknown spirolides as inferred from high-resolution mass spectrometry (HR-MS) and collision induced dissociation (CID) spectra revealed the presence of nine novel spirolides that have the pseudo-molecular ions m/z 670 (1), m/z 666 (2), m/z 696 (3), m/z 678 (4), m/z 694 (5), m/z 708 (6), m/z 720 (7), m/z 722 (8) and m/z 738 (9). Of the nine new spirolides proposed in this study, compound 1 was suggested to have a truncated side chain in lieu of the commonly observed butenolide ring in spirolides. Moreover, there is indication that compound 5 might belong to new spirolide subclasses with a trispiroketal ring configuration having a 6:5:6 trispiroketal ring system. On the other hand, the other compounds were proposed as C- and G-type SPX, respectively. Compound 7 is proposed as the first G-type SPX with a 10-hydroxylation as usually observed in C-type SPX. This mass spectrometry-based study thus demonstrates that structural variability of spirolides is larger than previously known and does not only include the presence or absence of certain functional groups but also involves the triketal ring system.

INFLUENCE OF CLIPPING HEIGHT ON THE NEUTRAL CARBOHYDRATE LEVELS OF ROOT EXUDATES OF ALFALFA PLANTS GROWN UNDER GNOTOBIOTIC CONDITIONS

1972 ◽  
Vol 52 (4) ◽  
pp. 643-649 ◽  
Author(s):  
R. A. HAMLEN ◽  
F. L. LUKEZIC ◽  
J. R. BLOOM
Keyword(s):  
Root Exudates ◽  
Dry Weight ◽  
Root Tissue ◽  
Minor Components ◽  
Flower Buds ◽  
Total Sugars ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Mature Leaves ◽  
Carbohydrate Levels

Influence of clipping height on neutral carbohydrate levels in root exudates of alfalfa grown gnotobiotically was investigated by gas-chromatographic and mass-spectral techniques. Exudates were obtained from plants that were lightly clipped (removal of flower buds), intermediately clipped (15 cm), and severely clipped (removal of all but four mature leaves). Glucose, inositol, sucrose, and four unidentified (U) components were detected. Fluctuations in the level of sugars were observed in exudates from two sampling periods. Glucose and U1 were most concentrated under light clipping. Levels of inositol and sucrose were maximum under intermediate clipping. Amounts of U3 were greatest from severely clipped plants, whereas levels of U5 remained constant at all cuttings. Concentration of U4 was lowest under severe clipping. U2, present in exudates from seedling plants, was not detected. Quantities of sugars released per gram of dry weight of root tissue were greater under severe clipping. U1 was the major component, with glucose, inositol, and sucrose minor components of the total sugars.

scholarly journals Mass spectral and theoretical investigations of the transient proton-bound dimers on the cleavage processes of the peptide GHK and its analogues

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4077-4086
Author(s):  
Jinhu Wang ◽  
Cheng Wang ◽  
Han Zhang ◽  
Yang Liu ◽  
Tiesheng Shi
Keyword(s):  
Mass Spectrometry ◽  
Theoretical Calculations ◽  
Mass Spectral ◽  
Protonated Peptides ◽  
Fragmentation Mechanisms ◽  
Theoretical Investigations

Fragmentation mechanisms of the singly protonated peptides GHK, GHKH and HGHK have been investigated by mass spectrometry and theoretical calculations.

Solid state chemical ionization for characterization of organic compounds by laser mass spectrometry

Talanta ◽  
1989 ◽  
Vol 36 (1-2) ◽  
pp. 117-124 ◽  
Author(s):  
Kesagapillai Balasanmugam ◽  
Somayajula Kasi Viswanadham ◽  
David M. Hercules
Keyword(s):  
Mass Spectrometry ◽  
Solid State ◽  
Organic Compounds ◽  
Chemical Ionization ◽  
Laser Mass Spectrometry ◽  
State Chemical

scholarly journals Desorption/Ionization Fluence Thresholds and Improved Mass Spectral Consistency Measured Using a Flattop Laser Profile in the Bioaerosol Mass Spectrometry of SingleBacillusEndospores

2005 ◽  
Vol 77 (22) ◽  
pp. 7448-7454 ◽  
Author(s):  
Paul T. Steele ◽  
Abneesh Srivastava ◽  
Maurice E. Pitesky ◽  
David P. Fergenson ◽  
Herbert J. Tobias ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectral ◽  
Desorption Ionization ◽  
Bioaerosol Mass Spectrometry ◽  
Laser Profile
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