A comparative study of in- and post-source decays of peptide and preformed ions in matrix-assisted laser desorption ionization time-of-flight mass spectrometry: effective temperature and matrix effect.
In-source decay (ISD) and post-source decay (PSD) of a peptide ion ([Y(6) + H](+)) and a preformed ion (benzyltriphenylphosphonium, BTPP) generated by matrix-assisted laser desorption ionization (MALDI) were investigated with time-of-flight mass spectrometry. α-Cyano-4-hydroxycinammic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) were used as matrices. For both ions, ISD yield was unaffected by delay time, indicating rapid termination of ISD. This was taken as evidence for rapid expansion cooling of hot "early" plume formed in MALDI. CHCA was hotter than DHB for [Y(6) + H](+) while the matrix effect was insignificant for BTPP. The "early" plume temperature estimated utilizing previous kinetic results was 800-900 K, versus 400-500 K for "late" plume. The results support our previous finding that the temperature of peptide ions interrogated by tandem mass spectrometry was lower than most rough estimates of MALDI temperature.
Yoon
So Hee
SH
Department of Chemistry, Seoul National University, Seoul, Korea.
Moon
Jeong Hee
JH
Kim
Myung Soo
MS
D001593:Benzyl Compounds / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry; D005841:Gentisates / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013696:Temperature
D001593:Benzyl Compounds; D003373:Coumaric Acids; D005841:Gentisates; D007477:Ions; D010455:Peptides; C007175:alpha-cyano-4-hydroxycinnamate; C010925:2,5-dihydroxybenzoic acid