Edmonds C G, Vestal M L, McCloskey J A
Nucleic Acids Res. 1985 Nov 25;13(22):8197-206. doi: 10.1093/nar/13.22.8197.
Nucleosides dissolved in aqueous buffered solutions undergo ionization during direct introduction of the solution into a mass spectrometer using a thermospray interface. The principal ions formed represent the protonated molecule, the corresponding protonated free base, and sugar. In addition to potential utility for characterization of new nucleosides, the technique can be used to monitor nucleosides separated from enzymatic hydrolysates by liquid chromatography. The selectivity of chromatographic detection is significantly greater than with UV absorbance alone so that independent detection of components of unresolved chromatographic peaks is usually possible. Detection limits, with signal/noise greater than 10 for most nucleosides, are approximately 0.1-1 ng per component for selected ion monitoring and 10-50 ng for full-scan mass spectra. Examples are given from the detection of modified nucleosides in enzymatic hydrolysates of 0.05 A260 units (2.5 micrograms) of rabbit liver tRNAVal and of unfractionated H. volcanii tRNA.
溶解于水性缓冲溶液中的核苷，在使用热喷雾接口将溶液直接引入质谱仪的过程中会发生离子化。形成的主要离子代表质子化分子、相应的质子化游离碱和糖。除了在表征新核苷方面具有潜在用途外，该技术还可用于监测通过液相色谱从酶解产物中分离出的核苷。色谱检测的选择性明显高于单独使用紫外吸收，因此通常可以对未分离的色谱峰的组分进行独立检测。对于大多数核苷，信号/噪声大于10时，选择离子监测的检测限约为每个组分0.1 - 1 ng，全扫描质谱的检测限为10 - 50 ng。文中给出了从0.05 A260单位（2.5微克）兔肝tRNAVal和未分级的火山口嗜热栖热菌tRNA的酶解产物中检测修饰核苷的示例。
