Polyaniline-poly (methylene blue) nano-rod composites as an electrochemical sensor for sensitive determination of ascorbic acid

Polyaniline-poly (methylene blue) nano-rod composite has been prepared by a chemical oxidative polymerization method. The PANI-PMB composite was characterized by scanning electron microscopy, spectrophotometry, Fourier transforms infrared spectrometry, and X-ray diffraction. The electrochemical performance of the PANI-PMB composite was studied by electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. The prepared nanocomposite was applied for the electrochemical sensing of ascorbic acid. The results show that the PANI-PMB modified carbon paste electrode (PANI-PMB/CPE) had better catalytic activity to the electrochemical oxidation of ascorbic acid compared with PANI/CPE, PMB/CPE and CPE, which was due to the fast electron transfer efficiency of the PANI-PMB composite. Under the optimized experimental conditions, the differential pulse voltammetric peak current was linear with the ascorbic acid concentration in the range from 4 to 110 μM with a detection limit of 1.3 μM. Furthermore, the proposed method has been applied for the determination of ascorbic acid content in vitamin C tablets.