Amperometric sensor based on a graphene/copper hexacyanoferrate nano-composite for highly sensitive electrocatalytic determination of captopril

In this work, a bi-layer modified glassy carbon electrode (GCE) was prepared by depositing appropriate amounts of multilayered graphene (GR) on the surface of GCE, followed by electrodepositing copper hexacyanoferrate (CuHCF) nano-particles on the graphene layer. The combination of graphene and CuHCF considerably improved the current response of the GCE towards the oxidation of captopril. Studies showed that the best response of the modified electrode could be achieved within neutral pHs. At a fixed potential under hydrodynamic conditions (stirred solutions), the oxidation current is proportional to the captopril concentration and the calibration plots were linear over the concentration ranges of 0.2 to 5.8μM and 5.8 to 480μM. The detection limit of the method was 0.09μM. The modified electrode was used for electrocatalytic determination of captopril in some real samples. ► A graphene/copper hexacyanoferrate nano-composite (CuHCF/GR) was prepared ► The composite showed improved electrocatalytic response towards captopril oxidation ► The best response was achieved within neutral pHs ► The composite electrode can be used as an amperometric sensor for captopril detection