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Keywords:

  • biosensors;
  • catalysis;
  • electrochemistry;
  • H2O2 reduction;
  • polyaniline;
  • Prussian blue;
  • uric acid

Abstract

Polyaniline/Prussian blue (PANI-PB) composite was electrochemically deposited on a platinum electrode. The properties of the PANI-PB-modified electrode were exploited in terms of its response toward H2O2 sensing by using cyclic voltammetry, and were found to be more effectual than the PANI-modified electrode in the low-potential range. The PANI-PB-modified electrode was further used for the bioanalysis of uric acid by immobilization of the enzyme uricase. The electrode was characterized at various stages of modification by scanning electron microscopy (SEM), IR spectroscopy, and cyclic voltammetry. The biosensor gave a linear response for uric acid in the concentration range 10–160 μM with a sensitivity of 160 μA mM−1 cm−2. The main advantage of the PANI-PB composite electrode is its low working potential (0 V vs. Ag/AgCl) for the estimation of uric acid, which enables the elimination of plausible interfering effects caused by analytes present in real samples. The biosensor was selective to uric acid and did not respond to analytes such as ascorbic acid, glucose, and urea. The sensor electrode retained its selectivity and sensitivity for seven days if stored at −18 °C. The biosensor also displayed a satisfactory performance for the detection of uric acid in human blood serum samples.