Soft X-Ray-Induced Decomposition of Amino Acids: An XPS, Mass Spectrometry, and NEXAFS Study
Soft X-Ray-Induced Decomposition of Amino Acids: An XPS, Mass Spectrometry, and NEXAFS Study
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DOI：
10.1667/rr3114.1
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发表时间：
2004-03
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影响因子：
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通讯作者：
Y. Zubavichus;O. Fuchs;L. Weinhardt;C. Heske;E. Umbach;J. Denlinger;M. Grunze
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文献类型：
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作者：
Y. Zubavichus;O. Fuchs;L. Weinhardt;C. Heske;E. Umbach;J. Denlinger;M. Grunze
Zubavichus， Y., Fuchs， O., Weinhardt， L., Heske， C., Umbach， E., Denlinger， J. D.和Grunze， M.软x射线诱导氨基酸分解：XPS，质谱和NEXAFS研究。Radiat。Res. 161, 346-358（2004）。采用X射线光电子能谱法（XPS）和质谱法研究了超高真空软X射线（k α镁X射线源）照射下丙氨酸、丝氨酸、半胱氨酸、天冬氨酸和天冬氨酸5种氨基酸的分解。对比分析了XPS线形状、化学计量和残余气体组成的变化，表明分子有多种分解途径。原始分子的脱水、脱羧、脱羰基、脱氨和脱硫，同时伴有H2、H2O、CO2、CO、nh3和H2S的解吸，其速率取决于特定的氨基酸。半胱氨酸在碳、氧、氮k壳层和硫L2、3edge的NEXAFS光谱与XPS和质谱数据相补充，表明样品暴露于强软x射线同步加速器束下导致C-C和C-N双键和三键的形成。定性上，所研究的氨基酸辐射稳定性排序为：丝氨酸<丙氨酸<天冬氨酸<半胱氨酸<天冬酰胺。
Abstract Zubavichus, Y., Fuchs, O., Weinhardt, L., Heske, C., Umbach, E., Denlinger, J. D. and Grunze, M. Soft X-Ray-Induced Decomposition of Amino Acids: An XPS, Mass Spectrometry, and NEXAFS Study. Radiat. Res. 161, 346–358 (2004). Decomposition of five amino acids, alanine, serine, cysteine, aspartic acid, and asparagine, under irradiation with soft X rays (magnesium KαX-ray source) in ultra-high vacuum was studied by means of X-ray photoelectron spectrometry (XPS) and mass spectrometry. A comparative analysis of changes in XPS line shapes, stoichiometry and residual gas composition indicates that the molecules decompose by several pathways. Dehydration, decarboxylation, decarbonylation, deamination and desulfurization of pristine molecules accompanied by desorption of H2, H2O, CO2, CO, NH3and H2S are observed with rates depending on the specific amino acid. NEXAFS spectra of cysteine at the carbon, oxygen and nitrogen K-shell and sulfur L2,3edges complement the XPS and mass spectrometry data and show that the exposure of the sample to an intense soft X-ray synchrotron beam results in the formation of C-C and C-N double and triple bonds. Qualitatively, the amino acids studied can be arranged in the following ascending order of radiation stability: serine < alanine < aspartic acid < cysteine < asparagine.