Optimization of Value for Sensitive Detection of Uridine and Thymidine Nucleosides by MS.

Liquid chromatography-tandem mass spectrometry has been widely used to quantify modified nucleosides enzymatically released from RNA and DNA. Compared to MS/MS, MS offers higher specificity for analytes in complex sample matrices because coeluting chemical interferences can be more effectively filtered out. To date, the detection of uracil- and thymine-containing nucleosides and their modified derivatives still suffers from poor sensitivity, owing, in part, to their relatively low proton affinities. In this study, we explored various settings of values in the MS analysis of unmodified and chemically modified uridine and thymidine nucleosides on a linear ion trap mass spectrometer. Our results showed that increasing the value led to markedly improved sensitivities for detecting some of these nucleosides using MS. Our work suggests that optimizing the value constitutes a useful approach for the highly sensitive detection of modified nucleosides and other types of analytes by MS.