Electrochemical determination of nitrite and iodate by use of gold nanoparticles/poly(3-methylthiophene) composites coated glassy carbon electrode

A promising electrochemical sensor was fabricated by electrodeposition of gold nanoparticles on poly(3-methylthiophene) (P3MT)-modified glassy carbon electrode (GCE), forming a nano-Au/P3MT composites-modified GCE (nano-Au/P3MT/GCE). Field emission scanning electron microscope (FE-SEM) and electrochemical techniques were used for the characterization of these composites. It was found that nano-Au/P3MT layer was very uniform, and formed a kind of nanoporous structure. Electrochemical experiments showed that this proposed nano-Au/P3MT composites-modified electrode exhibited excellent electrocatalytic properties for nitrite and iodate. Amperometry revealed that there existed a good linear relationship between peak current with the concentration in the range of 10–1000 μM and the detection limit of 2.3 μM for nitrite and in the range of 5–500 μM and the detection limit of 1.4 μM for iodate. The proposed method has been used as an amperometric detector for analysis of nitrite and iodate in iodized table salt and results were satisfactory. The nano-Au/P3MT composites-modified electrode had good storage stability, reproducibility and anti-interference ability for promising practical application.