Preparation in-situ of carbon nanotubes/polyaniline modified electrode and application for ascorbic acid detection

• The CNTs/PANI chemically modified electrode is prepared in-situ without any binder.
• The obtained modified electrode detection limit to ascorbic acid is 1 × 10− 7 mol L− 1.
• The obtained modified electrode detection linear range to ascorbic acid is 1.0 × 10− 6–4.5 × 10− 4 mol L− 1.

A novel grown in-situ carbon nanotube/polyaniline chemically modified electrode (GSCNT/PANI-CME) was synthesized for the electrochemical detection of ascorbic acid (AA). First, nickel catalyst was obtained by direct current electrochemical deposition on a graphite electrode (GE) surface. Second, CNTs were grown in-situ to obtain CNTs chemically modified electrode (GSCNTs-CME) by catalytic chemical vapor deposition. Third, the grown CNTs were acid treated to carboxylate and remove nickel particles. Finally, PANI was prepared in-situ by electrochemical polymerization on the GSCNTs-CME to obtain GSCNTs/PANI-CME. The obtained electrodes were characterized by scanning electron microscopy and cyclic voltammetry. The results showed that CNTs grew uniformly on the GE surface and the original tubular structure was remained. PANI was uniformly coated on the surface of CNTs in the obtained composite, which was a typical three-dimensional network structure. The GSCNTs/PANI-CME exhibited an excellent electrocatalytic activity to AA. The oxidation peak current was increased linearly with the concentration of AA in the range from 1.0 × 10− 6 mol L− 1 to 4.5 × 10− 4 mol L− 1, with a detection limit of 1.0 × 10− 7 mol L− 1 (S/N = 3). The experimental data showed that the obtained electrode was selective, stable and reproducible. The recoveries were between 97.4% and 102.1%.