Voltammetric microanalysis of DNA adducts with osmium tetroxide,2,2'-bipyridine using a pyrolytic graphite electrode.
DNA and synthetic polynucleotides modified with a complex of osmium tetroxide with 2,2'-bipyridine (Os,bipy) produce specific voltammetric signals at pyrolytic graphite electrodes. Based on a sufficient potential separation between the peaks of Os,bipy-modified DNA (DNA-Os,bipy) and of free Os,bipy, and using an adsorptive transfer stripping voltammetric procedure involving extraction of free Os,bipy from the electrode by chloroform, DNA-Os,bipy can be determined in an excess of the free reagent. Under certain conditions, 140 pg of DNA-Os,bipy can be detected after a 5 min accumulation period. This analysis displays a more favorable sensitivity and a better selectivity for DNA structure than oxidation of DNA guanine moieties, and offers detection of osmium DNA markers at carbon electrodes.
Fojta
Miroslav
M
Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, CZ-612 65 Brno, Czech Republic.
Havran
Ludek
L
Kizek
René
R
Billová
Sabina
S