Quantitative reproducibility of mass spectra in matrix-assisted laser desorption ionization and unraveling of the mechanism for gas-phase peptide ion formation

2013 ◽  
Vol 48 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Sung Hee Ahn ◽  
Kyung Man Park ◽  
Yong Jin Bae ◽  
Myung Soo Kim
Keyword(s):  
Gas Phase ◽  
Mass Spectra ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Ion Formation ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Updating Evidence for Cationization of Polymers in the Gas Phase during Matrix-Assisted Laser Desorption/Ionization

2005 ◽  
Vol 11 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Scott D. Hanton ◽  
Kevin G. Owens ◽  
Cynthia Chavez-Eng ◽  
Anne-Mette Hoberg ◽  
Peter J. Derrick
Keyword(s):  
Gas Phase ◽  
Mass Spectra ◽  
Secondary Ion Mass Spectrometry ◽  
Laser Desorption ◽  
Bottom Layer ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Delayed Extraction ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Matrix-assisted laser desorption/ionization (MALDI) techniques have been developed to determine the chemical structure of a variety of industrial polymers. Despite the enormous popularity and power of MALDI, the details of the cationization mechanisms of the process are currently rather poorly understood. The MALDI cationization of polymer analytes was investigated previously by Hoberg and co-workers.1 They used layered samples to explore the role of gas-phase cationization in MALDI of polymers. This paper seeks to extend the work initiated by Hoberg and co-workers and update the results of the earlier work. The new experiments take advantage of a MALDI instrument with delayed extraction and show that separation in the initial acceleration region of the mass spectrometer is not a key component of cationization. Investigations of tri-layer samples by time-of-flight secondary ion mass spectrometry (ToF-SIMS) also show that there is considerable interaction among the layers. These interactions, specifically the solubility of the salts in the solvents, account for the presence of the bottom layer cation in the mass spectra. The absence of the top layer cation in the mass spectra is due to the inability of the polymer oligomers to penetrate that layer during desorption.

Non-linear photoelectron effect contributes to the formation of negative matrix ions in UV-MALDI

2016 ◽  
Vol 18 (29) ◽  
pp. 19574-19587 ◽  
Author(s):  
E. Alonso ◽  
R. Zenobi
Keyword(s):  
Electron Capture ◽  
Laser Desorption ◽  
Negative Ion ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Ion Formation ◽  
Positive Ions ◽  
Non Linear ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

The mechanism of negative ion formation in matrix-assisted laser desorption/ionization (MALDI) is less well understood than that of positive ions: electron capture, disproportionation, and liberation of negatively charged sample molecules or clusters have been proposed to produce the initial anions in MALDI.

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