Synthesis electroactive polyurea with aniline-pentamer-based in the main chain and its application in electrochemical sensor

The electrochemical oxidation of ascorbic acid (vitamin C, AA) on the surface of carbon paste electrode (CPE) modified with electroactive polyurea (EPU) was studied by using cyclic voltammetry. EPU, with aniline-pentamer-based in the main chain, was synthesized from oligoaniline and p-phenylenediamine by oxidative coupling polymerization. The well-defined molecular structure of the oligoaniline was confirmed by LC-Mass, 1H NMR and FTIR spectroscopy. The in situ chemical oxidation of the reduced form of soluble, EPU in N-methyl-2-pyrrolidone was monitored by UV–visible absorption spectra. Moreover, the electroactivity of the EPU was evaluated by performing electrochemical cyclic voltammetry studies. A linear relationship between the concentration of AA added and the change of peak current obtained, as shown by the linear calibration curve of the amperometric response of the CPE modified with EPU sensor to the concentration of AA (R2 = 0.996, n = 10). The limit of detection for the EPU-CPE was estimated 6.1 μM at signal/noise of 3.

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