Fabrication of nanocomposite electrochemical sensors with poly(3,4-ethylenedioxythiophene) conductive polymer and Au nanoparticles adsorbed on carboxylated nanocrystalline cellulose

Au nanoparticles (AuNPs) were prepared by reducing HAuCl₄ with NaBH₄, and then adsorbed uniformly on the surface of carboxylated nanocrystalline cellulose (CNCC). The obtained AuNPs/CNCC particles were doped into a conductive polymer of poly(3,4-ethylenedioxythiophene) (PEDOT) to yield a highly conductive nanocomposite, which was deposited onto a glassy carbon electrode (GCE) by an electrochemical method. The PEDOT/AuNPs/CNCC nanocomposite showed low electrochemical impedance and good electrocatalytic activity toward ascorbic acid. Based on this novel nanocomposite material, an amperometric sensor was developed for the detection of ascorbic acid with a detection limit as low as 0.29 μM. When operated at -0.15 V, the sensor detected ascorbic acid in the range of 0.88 μM to 15000 µM.