Detection of chemically induced DNA damage by derivative square wave voltammetry

Damage of DNA films after reaction with styrene oxide was detected using de rivative square wave voltammetry. Double-stranded (ds) DNA films with initi ally low backgrounds developed oxidation peaks for DNA bases during incubat ion with styrene oxide. Films were prepared on pyrolytic graphite (PG) elec trodes by casting mixtures of DNA with the poly(ester sulfonic acid) ionome r Eastman AQ38S or by covalent binding of DNA onto oxidized PG. While both types of films gave oxidation peaks in the region 0.6-1.1 V vs SCE after in cubations with styrene oxide, DNA/AQ films gave the best signal-to-backgrou nd ratios. Damage of DNA by reaction with styrene oxide under the electrode incubation conditions was confirmed by capillary electrophoresis. Total in tegrals of oxidation peaks increased with time of incubation with styrene o xide. Relative peak heights depended on the type of DNA in the order calf t hymus ds DNA > salmon sperm ds DNA > supercoiled ds DNA > highly polymerize d calf thymus ds DNA.