Stevenson E, Breuker K, Zenobi R
Department of Chemistry, Swiss Federal Institute of Technology (ETH), Universitatstrasse 16, CH-8092 Zurich, Switzerland.
J Mass Spectrom. 2000 Aug;35(8):1035-41. doi: 10.1002/1096-9888(200008)35:8<1035::AID-JMS34>3.0.CO;2-V.
A transfer of energy into the internal modes of the matrix and analyte is expected to occur during matrix-assisted laser desorption/ioniziation (MALDI) processes. Both the physical and thermochemical properties of the MALDI matrix used can influence the ion internal energy and analyte ion fragmentation. Here we report the effect of several MALDI matrices on the relative internal energy of the 2'-deoxyadenylyl-(3',5')-2'-deoxyguanosine (AG) anion. Relative internal energies were probed by low-energy collision-induced dissociation in a Fourier transform ion cyclotron resonance mass spectrometer. Sublimation temperatures of the matrices under study were also determined and found to lie between 409 and 455 K. Analyte ion internal and initial kinetic energies did not correlate with matrix sublimation temperatures. In contrast, a strong correlation between the relative internal energy of the analyte anions and the gas-phase basicity of the matrix anions was found. These results suggest that gas-phase proton transfer reactions play an important role in MALDI analyte ion formation and influence their internal energy and fragmentation behavior. Copyright 2000 John Wiley & Sons, Ltd.
在基质辅助激光解吸/电离（MALDI）过程中，预计会发生能量向基质和分析物内部模式的转移。所使用的MALDI基质的物理和热化学性质都会影响离子的内能和分析物离子的碎片化。在此，我们报告了几种MALDI基质对2'-脱氧腺苷基-(3',5')-2'-脱氧鸟苷（AG）阴离子相对内能的影响。通过傅里叶变换离子回旋共振质谱仪中的低能碰撞诱导解离来探测相对内能。还测定了所研究基质的升华温度，发现其介于409至455 K之间。分析物离子的内能和初始动能与基质升华温度无关。相反，发现分析物阴离子的相对内能与基质阴离子的气相碱度之间存在很强的相关性。这些结果表明，气相质子转移反应在MALDI分析物离子形成中起重要作用，并影响其内能和碎片化行为。版权所有2000 John Wiley & Sons, Ltd.
