Quantification of Pt bound to DNA using total-reflection X-ray fluorescence (TXRF)

Total-reflection X-ray fluorescence (TXRF), has been applied to a study of DNA platination kinetics of calf thymus in vitro, investigating the interca lation sequences of three Pt-containing medicines (cis-diamminedichloroplat inum(II) (cis-DDP), Pt-Berenil, and K2PtCl4) in DNA. The in vivo study was focused on the introduction process of the cis-DDP and the Pt-Berenil in He La cells. To quantify the amount of Pt bound to the DNA, TXRF needs a sampl e volume less than or equal to 1100 mu l. Pt concentrations from 3 to 30 ng ml(-1) were determined with a relative standard deviation between 2 and 8% . TXRF is shown as an alternative analytical technique for studying metal t races in a biochemical process.