Matrix-assisted laser desorption ionization time-of-flight mass spectrometry of DNA-Pt(II) complexes

Matrix-assisted laser desorption ionization (MALDI) time-of-flight mass spectrometry has been used to characterize the reaction products of the 18-mer deoxyribonucleotide d(AACGGTTAACCGTTAATT) with [Pt(NH3)3(H2O)]2+ and cis-[Pt(NH3)2(H2O)2]2+. Characteristic peaks corresponding to different monofunctional adducts (18-mer+n[Pt(NH3)3]) (n = 1, 2, 3 and 4) have been observed with the triamino-monoaqua complex. With the diamino-diaqua cis-Pt complex, formation of a chelate (18-mer+[Pt(NH3)2]) involving two adjacent guanines has been demonstrated. A good correlation between MALDI and polyacrylamide gel electrophoresis results is observed.