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Merck
  • Analysis of initial reactions of MALDI based on chemical properties of matrixes and excitation condition.

Analysis of initial reactions of MALDI based on chemical properties of matrixes and excitation condition.

The journal of physical chemistry. B (2012-07-18)
Yin-Hung Lai, Chia-Chen Wang, Chiu Wen Chen, Bo-Hong Liu, Sheng Hsien Lin, Yuan Tseh Lee, Yi-Sheng Wang
摘要

This investigation concerns the initial chemical reactions that affect the ionization of matrixes in matrix-assisted laser desorption/ionization (MALDI). The study focuses on the relaxations of photon energy that occur on a comparable time scale to that of ionization, in which the available laser energy is shared and the ionization condition is changed. The relaxations include fluorescence, fragmentation, and nonradiative relaxation from the excited state to the ground state. With high absorption cross section and long excited-state lifetime, photoionization of matrix plays an important role if sufficient laser energy is used. Under other conditions, thermal ionization of the molecule in the ground state is predicted to be one of the important reactions. Evidence of change in the branching ratio of initial reactions with the matrix and the excitation wavelength was obtained with α-cyano-4-hydroxycinnamic acid, sinapinic acid, 2,5-dihydroxybenzoic acid, and 2,4,6-trihydroxyacetophenone. These matrixes are studied by obtaining their mixed crystal absorption spectra, fluorescence properties, laser-induced infrared emission, and product ions. The exact ionization pathway depends on the chemical properties of matrixes and the excitation conditions. This concept may explain the diversity of experimental results observed in MALDI experiments, which provides an insight into the ensemble of chemical reactions that govern the generation of ions.

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Sigma-Aldrich
反式肉桂酸, ≥99%
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2,5-二羟基苯甲酸, 98%
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2,5-二羟基苯甲酸, matrix substance for MALDI-MS, >99.0% (HPLC)
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芥子酸, ≥98%, powder
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反式肉桂酸, 97%
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反式肉桂酸, ≥99%, FG
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龙胆酸 钠盐 水合物, ≥98%
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反式肉桂酸, natural, ≥99%, FCC, FG
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芥子酸, matrix substance for MALDI-MS, ≥99.0% (T)
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反式 -肉桂酸, analytical standard
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芥子酸, matrix substance for MALDI-MS, ≥99.5%, Ultra pure
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2,5-二羟基苯甲酸, matrix substance for MALDI-MS, ≥99.5% (HPLC), Ultra pure