Ion Intensity and Thermal Proton Transfer in Ultraviolet Matrix-Assisted Laser Desorption/Ionization
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- 作者：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
- 刊名：Journal of Physical Chemistry B
- 出版年：2014
- 出版时间：April 17, 2014
- 年：2014
- 卷：118
- 期：15
- 页码：4132-4139
- 全文大小：352K
- 年卷期：v.118,no.15(April 17, 2014)
- ISSN：1520-5207
文摘
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.