Optimization of an HPLC method for analyses of 32P-postlabeled DNA adducts

A further development of an HPLC method to analyze 32P-postlabeled DNA adducts is presented. The method is based on on-line detection of 32P radioactivity after separation by reversed-phase chromatography. The method has an advantage in that the postlabeling mixture can be injected directly into the HPLC system without any prior purification, with the background radioactivity on a low level. The analysis includes the whole range of substances from orthophosphate to non-polar DNA adducts, which makes it possible to analyze normal nucleotides and ATP together with DNA adducts. The analytical system has a high reproducibility and separates complex mixtures of DNA adducts. The slightly lower sensitivity compared to the TLC method is compensated for by the possibility of injecting large amounts of DNA into the system without affecting the analytical properties. The system can be applied to different DNA adducts as well as complex mixtures of DNA adducts.