Electroanalytical quantification of total dsDNA extracted from human sample using, an ionic liquid modified, carbon nanotubes paste electrode

• A paste electrode was prepared by mixing carbon nanotubes with an ionic liquid.
• The electrode was used to investigate the direct electrochemical behavior of dsDNA.
• The presence of IL greatly enhances the peak currents of guanine and adenine.
• dsDNA extracted from human buccal swabs was quantified using the new electrode.
• Detection limit of dsDNA is 16 pM, by applying differential pulse voltammetry.

Direct electrochemistry of dsDNA has been achieved by using an ionic liquid 1-butyl-4-methylpyridinium hexafluorophosphate modified carbon nanotubes paste electrode (IL-CNTPE). Oxidation peaks appeared at 0.93 and 1.26 V (vs. Ag/AgCl) on the IL- CNTPE after preconcentration of dsDNA in pH 5.0 acetate buffer, which were attributed to the oxidation of guanine and adenine residues on the dsDNA molecule structure. Based on the signal of guanine, under the optimal conditions, very low levels of dsDNA can be detected after 60 s accumulation with detection limits of 0.249 mg L− 16 pM. Additionally, human DNA from a healthy volunteer is determined by use of the IL-CNTPE and it is found to be 40 ± 2, 14 pM.

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