Publication

In this study, a hydrothermally treated chemically modified graphene (CG) and cationic polyelectrolyte (poly(diallyldimethylammonium chloride, PDDA) composite was successfully synthesized by using an ultrasonication technique. Several batches were prepared and tested for optimal loading of PDDA on the CG surface and for optimization of the electrochemical characteristics. The 0.2% of PDDA loading composite showed better response than the other composites and was used to fabricate a multi-sensing electrode. Platinum nanoparticles (PtNPs) were anchored on the composite-modified working electrode by using the seed-mediated growth method to fabricate a highly selective and sensitive sensor for ascorbic acid (AA), dopamine (DA) and uric acid (UA) detection. The as-fabricated hybrid electrode sensor showed excellent catalytic activity with high sensitivity of 200.65, 635.48 and 88.11 μA/mMcm², wide detection range of 0.001–3.4, 0.0005-0.31 and 0.001-0.62 mM and short response time of 4, 4 and 5 s, for AA, DA and UA, respectively. The limits of detection, stability and reproducibility of the multi-sensors were also examined. In addition, biomolecule levels in human urine were investigated for the practical assessment of the proposed electrochemical sensor. The obtained results imply that the nanostructured electrode with high surface area and electrocatalytic activity offers great commitment for use in nonenzymatic electrochemical sensor applications.