A label-free electrochemical aptasensor for the analysis of the potassium ion

Herein, a simple and novel electrochemical method for the detection of potassium ions (K(+)) was developed. In the presence of potassium ions, the potassium ions aptamer will form a G-quadruplex complex. Thus, further addition of hemin in the presence of potassium ions will lead to the formation of a recombined G-quadruplex. Then the electroactive label, hemin, will give an electrochemical response. The linear range of the method covered a large variation of K(+) concentration from 0.1 nM to 0.1 μ M and the detection limit of 0.1 nM was obtained. Moreover, this assay was able to detect K(+) with high selectivity and had great potential applications.