Fujii Kentaro, Akamatsu Ken, Yokoya Akinari
Radiation Risk Analysis Laboratory, Japan Atomic Energy Research Institute, 2-4 Shirakatashirane, Tokai, Ibaraki 319-1195 Japan.
Int J Radiat Biol. 2004 Nov-Dec;80(11-12):909-14. doi: 10.1080/09553000400017721.
To compare the molecular decomposition of 2-deoxy-D-ribose induced by 0.6 keV electron irradiation or by 0.5keV ultrasoft X-ray irradiation.
A thin film of 2-deoxy-D-ribose was irradiated by two radiation sources: low-energy (approximately 0.6 keV) electrons and ultrasoft X-rays (approximately 0.5 keV). The positive ions that were desorbed from the sample during the irradiation were measured using a quadrupole mass spectrometer. The spectral changes in the X-ray absorption near edge structure (XANES) were also examined after the irradiation.
The ions that were desorbed from 2-deoxy-D-ribose due to electron irradiation were mainly H+, CHx+, C2Hx+, CO+, CHxO+, C3Hx+, C2HxO+ and C3sHO+ (x=1, 2, and 3) ions. These ions were the same as those observed in desorption due to ultrasoft X-ray irradiation. The XANES spectral changes induced by electron irradiation showed C-O bond cleavage in the molecule and C=O bond formation in the surface residues. These results show that intensive molecular decomposition of the furanose ring structure was induced by both types of irradiation. It is inferred that these irradiation products are primarily produced by secondary electrons (several tens of eV), which are thought to be generated by both types of irradiation when they are applied to the 2-deoxy-D-ribose sample.
比较0.6 keV电子辐照或0.5 keV极软X射线辐照诱导的2-脱氧-D-核糖的分子分解情况。
用两种辐射源对2-脱氧-D-核糖薄膜进行辐照：低能（约0.6 keV）电子和极软X射线（约0.5 keV）。使用四极质谱仪测量辐照过程中从样品解吸的正离子。辐照后还检查了X射线吸收近边结构（XANES）的光谱变化。
由于电子辐照从2-脱氧-D-核糖解吸的离子主要是H⁺、CHₓ⁺、C₂Hₓ⁺、CO⁺、CHₓO⁺、C₃Hₓ⁺、C₂HₓO⁺和C₃H₀⁺（x = 1、2和3）离子。这些离子与极软X射线辐照解吸中观察到的离子相同。电子辐照引起的XANES光谱变化表明分子中的C-O键断裂以及表面残留物中C=O键形成。这些结果表明两种辐照均诱导了呋喃糖环结构的强烈分子分解。据推测，这些辐照产物主要由二次电子（几十电子伏特）产生，当这两种辐照应用于2-脱氧-D-核糖样品时，二次电子被认为是由它们两者产生的。
