The fabrication of a carbon nanotube film on a glassy carbon electrode and its application to determining thyroxine

An easy and convenient technique to fabricate a carbon nanotube (CNT) film on a glassy carbon electrode (GCE) is described. In the presence of a hydrophobic surfactant, insoluble multi-walled carbon nanotubes (MWNTs) were dispersed into water to give a homogeneous and stable suspension. After solvent evaporation, a stable and uniform CNT film was achieved on the GCE surface. The MWNT film was characterized by scanning electron microscopy and transmission electron microscopy images. The electrochemical behaviour of thyroxine at the MWNT film-coated GCE was investigated. It was found that this novel CNT film can remarkably enhance the sensitivity of determination of thyroxine. Consequently, a novel electrochemical method was developed for the determination of thyroxine with simplicity and high sensitivity. The analysis method is demonstrated by using human blood serums.