Observation and prevention of an artefactual formation of oxidized DNA bases and nucleosides in the GC-EMS method

摘要: Gas chromatography coupled to electron impact mass spectrometry (GC-EIMS) analysis following hydrolysis of DNA is a widely used assay for the detection oxidized nucleobases and nucleosides. However, evidence was recently provided an oxidation guanine residues hydrolysed during silylation prior GC-EIMS analysis. This reaction accounts overestimation yield 8-oxo-7,8-dihydroguanine by GC-EIMS. In present work, we showed that adenine, cytosine, thymine thymidine also give rise derivatives derivatization. inferred from measurement amount 5-formyluracil, 5-hydroxymethyluracil, 5-hydroxycytosine (5-OHCyt), 8-oxo-7,8-dihydroadenine (8-OxoAde) 5-hydroxymethyl-2'-deoxyuridine (5-HMdUrd) in series experiments based on use purified bases Isotopically labelled 5-HMdUrd were as internal standards control quantitative aspect reaction. Support artefactual comparison 8-OxoAde 5-OHCyt detected within native gamma-irradiated HPLC-EC To prevent formation silylation, approach HPLC prepurification developed remove precursors measured sample. The HPLC/GC-EIMS successfully applied quantitation calf thymus DNA. addition, dose-dependent isolated exposed ionizing radiation achieved using same approach.