A hydrogel electrochemical electrode for simultaneous measurement of cadmium ions and lead ions

It is a challenging task to simultaneously, sensitively, reliably and conveniently measure heavy metal ions. In this work, a gelatin and carbon fiber composite-based (CF/GLN) hydrogel electrode was developed for Cd2+ and Pb2+ detection. The affecting factors for electrochemical behavior have been explored, including the curing time of gelatin and glutaraldehyde, the weight ratio of gelatin, the weight ratio of carbon fiber in gelatin. To enhance the selectivity and sensitivity of the hydrogel electrode, the zinc nanoparticles (ZnNPs) were modified onto the surface of the hydrogel electrode, as well as the modification condition of the ZnNPs was optimized. The experimental results showed that the ZnNPs@CF/GLN hydrogel electrode exhibited good electrochemical performance and higher electrocatalytic behavior response to Cd2+ and Pb2+. The wide linear range (0.1 mu M to 10 mu M for Cd2+, 0.05 mu M to 10 mu M for Pb2+) and the low detection limit (60 nM for Cd2+, 25 nM for Pb2+, S/N = 3) were obtained. Furthermore, to demonstrate the feasibility of the sensor, the amounts of Cd2+ and Pb2+ in real human serum samples were tested by differential pulse voltammetry (DPV), which showed a good recovery rate and practical applicability.

Automated summary

A novel hydrogel electrode for simultaneous detection of Cd2+ and Pb2+ was developed, showing good electrochemical performance and sensitivity in experiments. By optimizing the modification conditions, the selectivity and detection limit of the hydrogel electrode can be improved, making it suitable for detecting heavy metal ions in real human serum samples.