Laser desorption-ionization FT-ICR mass spectrometry: DNA-adduct bases, nucleosides and nucleotides

DNA-adduct formation is of particular importance in the evaluation of exposure to carcinogens, since it may be the critical initial event that ultimately results in adverse effects, e.g. tumor formation; such manifestations may not be observed until months or years following exposure. We have been investigating DNA-adduct formation following exposure of experimental animals to certain carcinogens, e.g. diethylnitrosamine and ethylcarbamate. Bases such as 7-ethylguanine, O6-ethylguanine and 1,N6-ethenoadenine, from DNA adducts can be monitored with HPLC and characterized by mass spectrometry. Nucleosides, nucleotides and other high molecular weight compounds from DNA adducts often have very low vapor pressures and are thermally unstable. Such compounds cannot be directly analyzed by conventional mass spectrometry. Using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry with IR laser desorption/ionization (LD/I), molecular or pseudomolecular ions of these compounds can be obtained fairly easily. LD/I of these and other involatile and thermally sensitive compounds will be discussed. © 1990.

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Author David E. Hinton Environmental Sciences and Policy