Ultra sensitive determination of Cadmium (II) using Ag-Au BMNPs–aptamer–modified glassy carbon electrodes (GCE)

Purpose The purpose of this study is determination of cadmium using silver-gold bimetallic nanoparticles (Ag-Au BMNPs) and an aptamer modified glassy carbon electrode. Design/methodology/approach The maximum response of modified electrode was obtained with, 50 mV pulse amplitude, 20 mV/s scan rate in phosphate buffer of pH 4.0. Ag-Au BMNPs, as the mediators improved electron transmit during the entire electron transfer process and the aptasensor response. Herein, the authors used aptamer as the capture probe to prepare an aptasensor with enhanced stability. Findings The proposed aptasensor exhibited a wide linearity to cadmium in the range of 0.001–0.100 µg/L with a low detection limit of 0.005×10 −3 µg/L. The glassy carbon electrodes with Ag-Au BMNPs showed a lower detection limit. Originality/value This aptasensor has good reproducibility, stability and repeatability and is cost-effective to regenerate. The specificity and selectivity of the novel modified electrode is tested in the presence of other interfering metal ions such as Fe 2+ , Mn 2+ , Mg 2+ , Sb 3+ and Bi 3+ . The aptasensor shows 10 times more sensitivity and selectivity for Cd 2+ ions.