Publication

We proposed and fabricated a miniaturized, flexible, and fully integrated electrochemical sensor incorporated with micro-patterned reduced graphene oxide (rGO) and a carbon nanotube (CNT) composite working electrode on a flexible gold substrate. By in situ plating bismuth film, the fabricated sensor exhibited well-defined and separate stripping peaks for cadmium (Cd) and iron (Pb) ions, respectively. The CNT was mixed with the rGO in order to improve the performance of the sensor by increasing the electrode surface area. Several experimental parameters, including an electrolyte environment and electrodeposition conditions, were also carefully optimized to achieve the best stripping performance. Under optimal conditions, high sensitivities of 262 nA/ppbcm² (Cd) and 926 nA/ppbcm² (Pb) along with favorable detection limits of 0.6 ppb (Cd) and 0.2 ppb (Pb) were obtained. The sensor exhibited good linear responses to both ion types in the concentration range of 20 ppb to 200 ppb. Due to the enlargement of the electrode surface area, the determination efficiency toward target ions was significantly enhanced by the developed Au/rGOCNT/Bi modified electrode. The developed sensor shows high sensitivity, stability, and reliability for the detection of the target heavy metal ions. Finally, the fabricated sensor was successfully demonstrated to detect the target metal ions in drinking water samples with satisfactory results.