title: Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization.
abstract: The ion-to-neutral ratios of four commonly used solid matrices, α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI.
authors: Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan.
authors: I-Chung
authors: IC
authors: Lu
authors: Kuan Yu
authors: KY
authors: Chu
authors: Chih-Yuan
authors: CY
authors: Lin
authors: Shang-Yun
authors: SY
authors: Wu
authors: Yuri A
authors: YA
authors: Dyakov
authors: Jien-Lian
authors: JL
authors: Chen
authors: Angus
authors: A
authors: Gray-Weale
authors: Yuan-Tseh
authors: YT
authors: Lee
authors: Chi-Kung
authors: CK
authors: Ni