نتایج جستجو برای: mass spectrometer source

تعداد نتایج: 885953  

2010
M-J Cheng V. Cvicek Luther W. Beegle

Introduction: NASA's Cassini Cassini's Ion and Neutral Mass Spectrometer (INMS) has returned a wealth of data on the composition of Titan's upper atmosphere and the plumes of Enceladus. However the encounter velocity (up to 17.73 km/sec) of the spacecraft with the plume or atmosphere has profound effects on the fragmentation of the observed molecules. Measured compositional changes of H 2 O, H ...

2017
Rui Su Xinchen Wang Changming Hou Meiling Yang Keke Huang Huanwen Chen

Rapid qualitative and quantitative analysis of solid samples (e.g., pharmaceutical preparations) by using a small and low-resolution mass spectrometer without MS/MS function is still a challenge in ambient pressure ionization mass spectrometric analysis. Herein, a practically efficient method termed microwave-enhanced in-source decay (MEISD) using microwave plasma torch desorption ionization co...

Journal: :The Analyst 2016
K M Evans-Nguyen J Gerling H Brown M Miranda A Windom J Speer

A microwave plasma was used for direct ambient ionization mass spectrometry of solid substrates, rapidly yielding atomic spectra without sample digestion or pre-treatment. Further, molecular spectra for the organic components of the substrate were obtained simultaneously, in an ambient ionization format. Initial characterization of the microwave plasma coupling to an ion trap mass spectrometer ...

Journal: :Journal of the American Society for Mass Spectrometry 2004
Joo Yeon Oh Jeong Hee Moon Myung Soo Kim

A tandem time-of-flight mass spectrometer for the study of photodissociation of biopolymer ions generated by matrix-assisted laser desorption ionization was designed and constructed. A reflectron with linear and quadratic (LPQ) potential components was used. Characteristics of the LPQ reflectron and its utility as the second stage analyzer of the tandem mass spectrometer were investigated. Perf...

1999
Shigeo MARUYAMA Masamichi KOHNO Shuhei INOUE

Chemical reaction of small silicon cluster ions Sin (11 ≤ n ≤ 20) with ethylene was studied with a newly implemented Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Silicon clusters were generated by a pulsed laser-vaporization supersonic-expansion cluster beam source directly connected to FT-ICR spectrometer. Injected and size selected silicon clusters were thermalized to...

Journal: :Journal of the American Society for Mass Spectrometry 2000
C A Srebalus J Li W S Marshall D E Clemmer

A combinatorial tripeptide library having the general form D-Glu-Xxx-Xxx-CONH2 has been synthesized using a standard mix and split synthetic protocol that is expected to produce 676 components. All components of the mixture were analyzed using a new high-resolution ion mobility/time-of-flight mass spectrometer coupled with an electrospray ionization source. In this approach ions are separated b...

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