Base damage detected by gas chromatography-mass spectrometry with selected ion monitoring

Base damage detected by gas chromatography-mass spectrometry with selected ion monitoring 

in pulse radiolysis studies, attempts are made to detect base-damage radical centres optically. This is not so easy for duplex DNA, because there are many possible structures and optical spectra are rather broad and featureless. 

Considerable success is now being achieved using analytical methods after exposure. The DNA is broken down into monomeric units which are first separated chromatographically, then analysed with a mass spectrometer with selected ion monitoring (SIM). 

The products of hydroxyl radical-mediated DNA scission (Dizda-roglu, 1986 Von Sonntag, 1987) include (Fig. 8.2) 5,6-dihydrothymine, 

One of the best techniques is the combination of gas-chromatography and selective ion monitoring using a mass spectrometer. This is briefly described in Section 7.8. It depends on prior knowledge of the types of modified bases that are expected and their ionization patterns in the mass spectrometer. 

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