Fabrication of an electrochemical sensor based on nanostructured polyaniline doped with tungstophosphoric acid for simultaneous determination of low concentrations of norepinephrine, acetaminophen and folic acid

摘要

Nanostructured polyaniline (PANI) doped with tungstophosphoric acid (TPA) was prepared; its structure was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). An electrochemical sensor was fabricated in a simple way by modification of carbon paste electrode with this nanostructured material (CPE-PANI/TPA). Because of the catalytic activity of TPA and the unique properties of PANI, this sensor was used for catalytic determination of norepinephrine (NE), acetaminophen (AC) and folic acid (FA), individually and simultaneously. Cyclic voltammetry experiments showed that the oxidation potential of these substances shifted to negative values and their oxidation current increased sharply by use of this sensor rather than by use of bare carbon paste electrode. Linear dynamic ranges and detection limits were obtained respectively as 8.0 × 10~(- 8)-2.0 × 10~(- 3) M and 5.0 × 10~(- 8) M for NE, 9.0 × 10~(- 7)-1.9 × 10~(- 3) M and 2.0 × 10~(- 7) M for AC and 2.0 × 10~(- 6)-2.1 × 10~(- 3) M and 3.0 × 10~(- 7) M for FA by differential pulse voltammetry. The proposed electrochemical sensor was used for the determination of these substances in pharmaceutical and blood serum samples.