Direct electrochemistry of double strand DNA on ionic liquid modified screen-printed graphite electrode

An ionic liquid modified screen-printed graphite electrode (SPE) was used for direct electrochemistry of herring sperm double strand DNA (dsDNA) by voltammetry. Due to the high conductivity of ionic liquid n-octylpyridinum hexafluorophosphate (OPPF), this electrode exhibited excellent electrochemical activity for the oxidation of dsDNA. Two irreversible oxidation peaks were obtained at the developed electrode, which corresponded to the oxidation of guanine and adenine residues present in the dsDNA. The basic electrochemical behavior of dsDNA at the OPPF modified SPE was carefully investigated. Combined with the differential pulse voltammetry, this electrode exhibited a good linear range from 20 μg mL−1 to 120 μg mL−1 with a detection limit of 5 μg mL−1 for the direct determination of dsDNA. Furthermore, the OPPF modified electrode displayed high reproducibility and stability for the dsDNA determination.

Research highlights
► Develop an ionic liquid doped screen-printing ink.
► Good electrochemical performance of ionic liquid modified electrode.
► Electrochemical determination of DNA on ionic liquid modified screen-printed graphite electrode.