Simultaneous sensing of copper, lead, cadmium and mercury traces in human blood serum using orthorhombic phase aluminium ferrite

We report a facile, one-step solid-state synthesis of aluminium ferrite (AFO) for simultaneous sensing of heavy metal ions (HMIs) namely cadmium (Cd2+), lead (Pb2+), copper (Cu2+) and mercury (Hg2+) in human blood serum. The nanoflake morphology and orthorhombic phase formation of the as-synthesised AFO were revealed through field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) pattern, respectively. The AFO modified glassy carbon electrode (AFO/GCE) exhibits distinct peak potentials for all HMIs with peak separation potential (Delta E-p) of 190 mV, 494 mV and 304 mV for Cd2+ -Pb2+, Pb2+ -Cu2+ and Cu2+ -Hg2+, respectively. Low limits of detection (LOD) of values 1.5 nM, 4 nM, 1.6 nM and 0.5 nM were observed for Hg2+ , Cd2+ , Pb2+ and Cu2+, respectively which are well below the limits of unsafe concentrations of HMIs reported for human blood. The excellent sensitivity and low LOD can be attributed to the octahedral sites of the AFO perovskite structure with Fe2+/Fe3+ oxidation states which favours the delocalization of charge accumulations at the electrode surface. The sensor is successfully in determination of HMIs in simulated human blood serum using standard addition technique with an excellent recovery percentage. This strategy outlined here can be effectively used for developing various sensing platforms for bioanalytical applications.