Sensitive determination of dopamine and uric acid by the use of a glassy carbon electrode modified with poly(3-methylthiophene)/gold nanoparticle composites.

A kind of novel nanocomposites, poly(3-methylthiophene) (P3MT)/gold nanoparticles (AuNPs), were successfully deposited onto the surface of a glassy carbon electrode. A field emission scanning electron microscope (FE-SEM) and electrochemical techniques were used for characterizing this modified electrode. The results showed that the AuNPs were inserted into a P3MT layer uniformly, and formed a porous 3D structure. This modified electrode showed excellent electrocatalytic activity towards the oxidation of ascorbic acid (AA), dopamine (DA) and uric acid (UA); the overlapping anodic peaks of AA, DA and UA were completely divided into three well-defined voltammetric peaks. A further study showed that there existed a linear relationship between the peak current and the concentration of DA in the range of 1.0 x 10(-6) to 3.5 x 10(-5) mol L(-1), and UA in the range of 1.0 x 10(-6) to 3.2 x 10(-5) mol L(-1). The detection limits were 2.4 x 10(-7) mol L(-1) for DA and 1.7 x 10(-7) mol L(-1) for UA. This proposed method was applied to the detection of real samples, and the results were satisfactory.