Ion intensity and thermal proton transfer in ultraviolet matrix-assisted laser desorption/ionization

I. Chung Lu, Chuping Lee, Hui Yuan Chen, Hou Yu Lin, Sheng Wei Hung, Yuri A. Dyakov, Kuo Tung Hsu, Chih Yu Liao, Yin Yu Lee, Chien-Ming Tseng, Yuan Tseh Lee, Chi Kung Ni*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The ionization mechanism of ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI) was investigated by measuring the total cation intensity (not including sodiated and potasiated ions) as a function of analyte concentration (arginine, histidine, and glycine) in a matrix of 2,4,6-trihydroxyacetophenone (THAP). The total ion intensity increased up to 55 times near the laser fluence threshold as the arginine concentration increased from 0% to 1%. The increases were small for histidine, and a minimal increase occurred for glycine. Time-resolved fluorescence intensity was employed to investigate how analytes affected the energy pooling of the matrix. No detectable energy pooling was observed for pure THAP and THAP/analyte mixtures. The results can be described by using a thermal proton transfer model, which suggested that thermally induced proton transfer is crucial in the primary ion generation in UV-MALDI.

Original languageEnglish
Pages (from-to)4132-4139
Number of pages8
JournalJournal of Physical Chemistry B
Issue number15
StatePublished - 17 Apr 2014

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