Determination of mercury cation using electrode modified with phosphorothioate oligonucleotide

• PTO-modified electrodes for the determination of mercury cation were developed.
• PTO was immobilized by adsorption on glassy carbon electrode.
• Methylene blue was used as a redox marker for the generation of current signal.
• High selectivity towards mercury cation and lower detection limit of 2.34 × 10−11 mol L−1 were observed.

A novel electrochemical biosensor for the determination of mercury ion is described. The receptor layer was formed on glassy carbon electrode by adsorption of phosphorothioate oligonucleotide (PTO). The presence of sulfur atom in the backbone of modified nucleotide allows for strong interaction with Hg2+. The optimized sensor distinguishes itself with high selectivity towards mercury ions and lower detection limit of 2.34 × 10−11 mol L−1. For tested PTO sequence, it was possible to determine the linear response in the Hg2+ concentration range of 10−11–10−7 mol L−1.

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