The analytical potential of mass spectrometry will be developed for applications involving analytical and structural studies of nucleic acid-derived materials. Thermospray LC/MS studies will be extended to include microcolumn LC techniques which will permit post-column reactions and solvent manipulations prior to vaporization. Tandem mass spectrometry, employing low-energy collision-induced dissociation of model nucleosides and nucleotides will be studied with regard to mode of primary ionization, optimization of sensitivity, and efficient utilization of tandem scan functions for sample-limited measurements. Emphasis will be placed on methods for microscale characterization of constituents of unknown structure directly in mixtures. Applications of the methods developed will be made to model mixture systems, including detection of modified nucleosides in enzymatic hydrolysates of nucleic acids.