The methyl‐modified nucleosides (methyladenosine, methylguanosine, methylcytidine, and methyluridine) occur widely in nucleic acids and serve as biomarkers for a variety of types of diseases. Their isomers have the same parent ions in MS spectra and need further discrimination. Here, electrospray ionization mass spectrometry (ESI‐MS) coupled with collision induced dissociation (CID) was used to distinguish the common isomerides of methyl‐nucleosides. The various fragmentation patterns had been discussed in comparison of the different methyl modified nucleosides and were studied as a function of normalized collision energy. Then, structurally relevant fragments were obtained to efficiently identify characterization of methyl‐nucleoside isomerides by collision induced dissociation. Therefore, this study provides a promising method using CID‐MS for the discrimination of the isomeric methyl nucleosides, which could be useful to quantitative study of methyl nucleosides and detect of unknown methyl nucleosides.

中文翻译：

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碰撞诱导解离串联质谱法鉴别甲基核苷的常见异构体

甲基修饰的核苷（甲基腺苷，甲基鸟苷，甲基胞苷和甲基尿苷）广泛存在于核酸中，并作为多种疾病的生物标记物。它们的异构体在MS光谱中具有相同的母离子，需要进一步区分。在这里，电喷雾电离质谱（ESI-MS）与碰撞诱导解离（CID）结合使用来区分甲基核苷的常见异构体。比较了不同的甲基修饰的核苷，讨论了各种片段化模式，并研究了它们与归一化碰撞能量的关系。然后，获得结构上相关的片段，以通过碰撞诱导解离有效地鉴定甲基核苷异构体的特征。所以，