Targeted comparative proteomics by liquid chromatography/matrix-assisted laser desorption/ionization triple-quadrupole mass spectrometry

2006 ◽  
Vol 20 (5) ◽  
pp. 904-910 ◽  
Author(s):  
Jeremy E. Melanson ◽  
Kenneth A. Chisholm ◽  
Devanand M. Pinto
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Laser Desorption ◽  
Comparative Proteomics ◽  
Triple Quadrupole ◽  
Laser Desorption Ionization ◽  
Quadrupole Mass ◽  
Desorption Ionization ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Gas-Phase Reactivity of Acylphenols in Electrospray and Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

2009 ◽  
Vol 15 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Isabelle Schmitz-Afonso ◽  
Vincent Guérineau ◽  
Alessandra Maia-Grondard ◽  
Khalijah Awang ◽  
Marc Litaudon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution Mass Spectrometry ◽  
Laser Desorption ◽  
Ion Source ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Acylphenols from Myristica crassa were identified based on liquid chromatography high-resolution mass spectrometry and liquid chromatography tandem mass spectrometry (MS/MS) experiments. Two types of compound were found in the extract of the plant: monomeric (malabaricone B and C) and dimeric compounds (C–C bonded biphenyl and C–C bonded phenyl–linear carbon chain). Evidence of formation of covalent dimeric ions during the electrospray ionization and matrix-assisted laser desorption ionization (MALDI) processes was established. [2M–3H]− dimeric ions were detected on the mass spectra of each monomeric compound during high-performance liquid chromatography separation. The MS/MS spectra of those species were compared to the MS/MS spectra obtained for the dimeric compounds synthesized by the plant. Fragmentation pathways were studied for the two classes of dimer. The dimeric ions formed in the ion source were C–C bonded biphenyl compounds. Further evidence was obtained from MALDI experiments: increase in the extraction delay time leads to an increase of the dimeric ions relative abundance. Their formation is based on the high reactivity of phenols or phenolate ions which are easily oxidized yielding phenoxy radicals.

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