Electrochemistry of deoxyribonucleic acid-cetyltrimethylammonium complex with considering O2 effect

The electrochemistry of deoxyribonucleic acid-cetyltrimethylammonium complex (DNA-CTMA) film is studied by cyclic voltammetry. DNA-CTMA film is electroactive, but the electrochemical redox processes are not reversible. The experimental results indicate that O2 can oxidize both guanine in CH2Cl2 and deprotonated guanine in aqueous NaOH electrolyte. O2 is responsible for the negative shift of the oxidation potential of guanine. The exclusion of O2 can protect guanine from chemical oxidation and result in reliable evaluation of HOMO (highest occupied molecular orbital) level based on the onset oxidation potential of DNA-CTMA. The HOMO level of DNA-CTMA is derived to be 5.68 eV from the cyclic voltammetry.