RESUMO
Objective::A new-type electrochemical sensor was developed by electrodepositing gold nanoparticle on the surface of glassy carbon electrode (GCE) modified by Nafion-multi-wall carbon nanotube (MWNTs) by the potentiostatic method, and used for the detection of rutin in practical samples. Method::The electrochemical properties of the sensor in potassium ferricyanide-potassium ferrocyanide system were studied by electrochemical impedance spectroscopy and cyclic voltammetric method, in order to explore the electrochemical performance of the sensor. The electrochemical behavior of rutin on the surface of the sensor was studied by the cyclic voltammetric method, and the factors affecting the performance of the sensor were optimized. The content of rutin was determined by differential pulse voltammetric methods. Result::The optimized conditions were -0.25 V of the deposition potential of gold nanoparticle, 20 s of the deposition time, pH 3.0, and 6 μL of 1 g·L-1 carbon nanotube. Under the conditions, a good linear relationship between reduction peak current and rutin concentration was obtained from 5.0 ×10-9 to 7.0 ×10-7 mol·L-1, and the detection limit was 3.6×10-9 mol·L-1. Conclusion::The developed sensor has a good electrical conductivity and stability, and is highly sensitive and simple for the detection of rutin, with a low detection limit. It has been successfully applied to the detection of rutin in Sophorae Immaturus Flos with the recoveries between 97.6%and 104.4%, which provides a new method for the determination of rutin and a new idea for the quality control of Chinese medicinal materials.