Characterization of Carbon Nanotubes Paste Electrode and its Application as Rutin Sensor

Carbon nanotubes paste electrodes (CNTPE) were prepared using carbon nanotube and mineral oil at different compositions. The carbon nanotubes/mineral oil content in the paste electrode was evaluated using cyclic voltammetry which was 60% (w/w) carbon nanotube. This electrode was characterized by SEM and EIS. The SEM results showed that CNTS structure is not modified by maceration process. From EIS analysis it is possible to observe that the electron transfer reaction is faster in the CNTs presence compared to graphite carbon. CNTPE with 60% (w/w) was used in the determination of rutin in pharmaceutical formulations. Using the differential pulse voltammetric (DPV) procedure, a linear analytical curve was observed in the 1.99x10-7- 9.99x10-6 mol L-1 range with detection limit of 3.39x10-8 mol L-1. The determination of rutin in pharmaceutical formulations showed to be in agreement with the standard spectrophotometric method, AOAC Method, with 95% confidence level and recoveries between 99.2 and 100.5%. The excellent results obtained suggest that the CNTPE 60% (w/w) is suitable for the determination of rutin in pharmaceutical formulations.