Enhancement of functional surface and molecular dynamics at Pt-rGO by spacer 1,6-hexanediamine for precise detection of biomolecules: uric acid as a specimen

The enhancement of a functional surface and molecular migration through reduced graphene oxide (rGO) with consequent detection of low-concentration uric acid (UA) is presented. We observed excellent molecular migration in an organic-inorganic composite, in which 1,6-hexanediamine (HA) was incorporated in rGO-platinum (Pt) matrices to obtain HA-rGO-Pt. The rGO, Pt and HA precursor played the roles of conductive template, electrocatalyst, and spacer group. As a sensing probe on a glassy carbon electrode (surface area 0.0316 cm2), the material afforded precise uric acid (UA) detection with a linear dynamic range (LDR) and sensitivity of 0.1 nM-0.1 mM UA and 24.2089 mu A mu M-1 cm-2. The signal to noise ratio was 3, and the lower limit of detection (LOD) was 39.22 +/- 1.96 pM. The high sensitivity and rapid detection of UA was possible due to the improved hydronium ion conductivity (similar to 10-5-10-4 S cm-1) and moderate electron conductivity. This strategy of widening the molecular migration track might be considered as a facile way to adopt graphene-based composites for various applications, including sensing and catalysis. Hexanediamine (HA) was incorporated in rGO-platinum (Pt) matrices to obtain HA-rGO-Pt with an improved molecular migration track. The HA-rGO-Pt could detect very low concentrations uric acid as the uric acid could migrate through the layers of rGO.