Method for detecting mercury ions through gold electrode modified by polythymidine DNA

The invention provides a method for detecting mercury ions through a gold electrode modified by polythymidine DNA, which is characterized in that polythymidine DNA molecule is taken as a recognition element for mercury ions, the gold electrode modified by polythymidine DNA is prepared, then mercury ions in an aqueous solution is detected by the prepared gold electrode, wherein alkali base T in DNA molecule is capable of specifically binding with mercury ions to form a stable T-Hg-T structure. The intensity of an electrochemical signal is relative with the concentration of mercury ions in the solution, so that the concentration of mercury ions in the aqueous solution can be calculated. According to the invention, the method for detecting mercury ions has the advantages of no pollution on environment, good selectivity on mercury ions, eliminated interference of most metal ions, high sensitivity, simple required apparatus and low cost, and is suitable for being applicable to such humble situations as fields