Abstract:
The objective of this study is to create a new electrochemical sensor for the sensitive and
specific detection of heavy metal ions (Cu2+, Ni2+, Pb2+, and Mn2+) in water by immobilizing
multi-functionalized graphene oxide (f-GO) on a TiO2 modified fluorine doped tin oxide
(FTO) glass electrode. Ammonia, thiourea, glucose, and oxalic acid were used to
functionalize the graphene oxide, which was synthesized by modified Hummers process.
The addition of amino, thiol, hydroxyl, and carboxyl functional groups enhanced the binding
affinity for metal ions. FTIR (Fourier Transform Infrared Spectroscopy) was used to validate
successful functionalization. Charge transfer resistance (RCT), which is inversely related to
ion concentration, was estimated using Electrochemical Impedance Spectroscopy (EIS) to
evaluate the performance of the sensor. The sensor shows the lowest RCT with a highest
sensitivity value of 1.04491 × 10-4 Ω-1 ppm-1 cm-2. The estimated detection limits were 2.89
ppm (Ni2+), 1.90 ppm (Pb2+), 3.06 ppm (Cu2+), and 1.78 ppm (Mn2+). Due to its high
selectivity for copper ions, the sensor offers a reliable and cost-effective method for detecting
harmful heavy metal contamination in water samples.
