| Electrogenerated chemiluminescence (also called electro-chemiluminescence and abbreviated ECL) is the process whereby species generated at electrodes undergo high-energy electron-transfer reactions to form excited states that emit light. ECL has been proven to be a novel and scientific analytical technique as it combines the advantage of chemiluminescence and electrochemistry. The ECL technology has been extensively applied in many fields because of its good reproducibility, high sensitivity, a wide range of analytical applications, low detection limit, convenience in operation, fast analyzing speed and good stability ect.Firstly, according to the previous literature, Ru(phen)3(PF6)2 and Os(phen)3(PF6)2 were synthesized. Compared with its luminescence properties, Ru(phen)3(PF6)2 that has a greater luminous intensity than Os(phen)3(PF6)2, what's more, luminous intensity were not obvious change when Os(phen)3(PF6)2 reacted with thymine. On the contrary, luminous intensity got further enhancement when Ru(phen)3(PF6)2 reacted with thymine (T). Ru(phen)3(PF6)2 was employed to quantitative determination of mercury (?) ions in the paper due to its excellent electrochemical luminescence performance.Secondly, a new method for determination of mercury (?) ions has been established based on ECL of Ru(phen)32+/thymine. The oxidation potential of Ru(phen)32+is E= 1.13 V and thymine has a oxidation potential that is E=0.53 V. Therefore, thymine is equal to the ECL reactant to react with Ru(phen)32+ to further enhance the ECL intensity. Due to the strong coordination effects of Hg+ and T, the complex T-Hg2+-T can be generated. It can make the concentration of T to be reduced in the Ru(phen)32+/thymine system so that the ECL intensity decreases. According to the change of the luminous intensity, the concentration of mercury (?) ion could be detected in a certain range. The experimental results indicate that the ECL of Ru(phen)32+/thymine was used to detect mercury (?) ion with a linear range of 1.0×10-9to 1.0×10-5 mol/L at bare glass carbon (GC) electrode in 0.1 mol/L phosphate butter (pH= 8), and the detection limit can be reached to 1.0×10-9 mol/L (S/N= 3) within a relative standard deviation of 5%, showing that this method not only has good reproducibility and stability, but also can be used for detection of mercury (?) ions.Finally, in order to further reduce the detection limit of mercury (?) ions, graphene oxide (GO) modified GC electrode were utilized to detect mercury (?) ions. The graphene oxide has a larger surface area and unique high conductivity, hence, GO can improve the sensitivity of electrochemical detection to reach the purpose of reducing mercury (?) ions detection limit. The linear range is 1.0×10-11 to 1.0×10-7 mol/L at GO-modified electrode, and the detection limit can be reduced further to 1.0×10-11 mol/L. Compared with bare GC electrode, the detection limit of mercury (?) ions drops by two orders of magnitude. Determination of mercury (?) ions has a lower detection limit by using the GO-modified electrode. Therefore, the result is satisfactory. |
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