scholarly journals Characterization of Phytoecdysteroid Glycosides in Meadowfoam (Limnanthes alba) Seed Meal by Positive and Negative Ion LC-MS/MS

2008 ◽  
Vol 56 (11) ◽  
pp. 3945-3952 ◽  
Author(s):  
Jan F. Stevens ◽  
Ralph L. Reed ◽  
Jeffrey T. Morré
Keyword(s):  
Negative Ion ◽  
Seed Meal ◽  
Limnanthes Alba

scholarly journals Chemical Evaluation of Eumelanin Maturation by ToF-SIMS and Alkaline Peroxide Oxidation HPLC Analysis

2020 ◽  
Vol 22 (1) ◽  
pp. 161
Author(s):  
Martin Jarenmark ◽  
Peter Sjövall ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu ◽  
Johan Lindgren
Keyword(s):  
Molecular Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Characterization ◽  
Experimental Treatment ◽  
Negative Ion ◽  
Pressure Treatment ◽  
Peroxide Oxidation ◽  
Specific Chemical ◽  
Tof Sims

Residual melanins have been detected in multimillion-year-old animal body fossils; however, confident identification and characterization of these natural pigments remain challenging due to loss of chemical signatures during diagenesis. Here, we simulate this post-burial process through artificial maturation experiments using three synthetic and one natural eumelanin exposed to mild (100 °C/100 bar) and harsh (250 °C/200 bar) environmental conditions, followed by chemical analysis employing alkaline hydrogen peroxide oxidation (AHPO) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Our results show that AHPO is sensitive to changes in the melanin molecular structure already during mild heat and pressure treatment (resulting, e.g., in increased C-C cross-linking), whereas harsh maturation leads to extensive loss of eumelanin-specific chemical markers. In contrast, negative-ion ToF-SIMS spectra are considerably less affected by mild maturation conditions, and eumelanin-specific features remain even after harsh treatment. Detailed analysis of ToF-SIMS spectra acquired prior to experimental treatment revealed significant differences between the investigated eumelanins. However, systematic spectral changes upon maturation reduced these dissimilarities, indicating that intense heat and pressure treatment leads to the formation of a common, partially degraded, eumelanin molecular structure. Our findings elucidate the complementary nature of AHPO and ToF-SIMS during chemical characterization of eumelanin traces in fossilized organismal remains.

Structural Characterization of Monosialo-, Disialo- and Trisialo-gangliosides by Negative Ion AP-MALDI-QIT-TOF Mass Spectrometry with MSn Switching

2012 ◽  
Vol 37 (6) ◽  
pp. 1315-1324 ◽  
Author(s):  
Emi Ito ◽  
Akio Tominaga ◽  
Hiroaki Waki ◽  
Kozo Miseki ◽  
Azusa Tomioka ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Structural Characterization ◽  
Negative Ion

scholarly journals Characterization of ions at Alpine waterfalls

2011 ◽  
Vol 11 (9) ◽  
pp. 25297-25325 ◽  
Author(s):  
P. Kolarž ◽  
M. Gaisberger ◽  
P. Madl ◽  
W. Hofmann ◽  
M. Ritter ◽  
...  
Keyword(s):  
Negative Ion ◽  
Moderate Increase ◽  
Field Campaign ◽  
Ion Gradients ◽  
Austrian Alps ◽  
Positive Ions ◽  
Ion Detector

Abstract. During a three-year field campaign of measuring waterfall generated ions, we monitored five different waterfalls in the Austrian Alps. Most measurements were performed at the Krimml waterfall (Salzburg), which is the biggest and most visited one in Europe and the Gartl waterfall (Mölltal, Carinthia). Smallest ion sizes (0.9–2 nm) were measured with a cylindrical air ion detector (CDI-06) while ion sizes from 5.5 to 350 nm were measured using a modified Grimm SMPS aerosol spectrometer. Measurements showed high negative ion gradients nearby waterfalls whereas positive ions showed only a moderate increase. The most abundant sizes of nano-sized and sub-micrometer ions measured were at 2 nm and of the larger and heavier ones at 120 nm.

scholarly journals Characterization of hydrogen plasma in a permanent ring magnet based helicon plasma source for negative ion source research

2019 ◽  
Vol 61 (6) ◽  
pp. 065003 ◽  
Author(s):  
A Pandey ◽  
Debrup Mukherjee ◽  
Dipshikha Borah ◽  
M Bandyopadhyay ◽  
Himanshu Tyagi ◽  
...  
Keyword(s):  
Hydrogen Plasma ◽  
Plasma Source ◽  
Ion Source ◽  
Negative Ion ◽  
Helicon Plasma ◽  
Ring Magnet

scholarly journals A binary matrix for the rapid detection and characterization of small-molecule cardiovascular drugs by MALDI-MS and MS/MS

2018 ◽  
Vol 10 (6) ◽  
pp. 572-578 ◽  
Author(s):  
Jinlan Dong ◽  
Wenjing Ning ◽  
Daniel J. Mans ◽  
Jamie D. Mans
Keyword(s):  
Small Molecule ◽  
Hydroxycinnamic Acid ◽  
Cardiovascular Drugs ◽  
Maldi Ms ◽  
Negative Ion ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Binary Matrix ◽  
Negative Ion Mode

A mixture of α-cyano-4-hydroxycinnamic acid and 1,5-diaminonaphthalene was discovered as a novel binary matrix for the qualitative analysis of 14 small-molecule (∼250–550 Da) cardiovascular drugs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and MS/MS in either positive or negative ion mode.

ChemInform Abstract: Structural Characterization of the Oligosaccharide Antibiotics Everninomicins by Negative Ion FAB and ESI/MS.

ChemInform ◽  
2001 ◽  
Vol 32 (11) ◽  
pp. no-no
Author(s):  
Birendra N. Pramanik ◽  
Petia A. Shipkova ◽  
Peter L. Bartner ◽  
Larry Heimark ◽  
Yan-Hui Liu ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Negative Ion ◽  
Esi Ms

Plasma characterization of a test setup of RF-driven negative ion source by a Langmuir probe system

2017 ◽  
Vol 858 ◽  
pp. 90-95 ◽  
Author(s):  
Peng Zhao ◽  
Dong Li ◽  
Dezhi Chen ◽  
Kaifeng Liu ◽  
Xiaofei Li ◽  
...  
Keyword(s):  
Langmuir Probe ◽  
Ion Source ◽  
Negative Ion ◽  
Test Setup ◽  
Probe System ◽  
Plasma Characterization

Characterization of Pine Pellet and Peanut Hull Pyrolysis Bio-oils by Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

2012 ◽  
Vol 26 (6) ◽  
pp. 3810-3815 ◽  
Author(s):  
Jacqueline M. Jarvis ◽  
Amy M. McKenna ◽  
Roger N. Hilten ◽  
K. C. Das ◽  
Ryan P. Rodgers ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Electrospray Ionization ◽  
Cyclotron Resonance ◽  
Negative Ion ◽  
Ion Cyclotron Resonance ◽  
Electrospray Ionization Fourier Transform ◽  
Ion Cyclotron ◽  
Peanut Hull
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