Developing a new electrochemical enzyme biosensor for highly sensitive determination of heavy metal ions

Aim. This work was purposed to develop a new electrochemical enzyme biosensor for the highly sensitive determination of heavy metal ions. Methods. The electrochemical transducers consisted of two pairs of gold-interdigitated electrodes that connected to the impedimetric measuring device. Urease was immobilized with glutaraldehyde on one electrode pair, while a reference membrane with BSA was prepared similarly. Measurements were conducted in 5 mM PBS (pH 7.35) using differential mode to compensate for non-specific signal variations. Results. The biosensor detected multiple HMIs with high sensitivity and showed high work reproducibility (RSD = 2.28%). EDTA treatment successfully restored enzyme activity, allowing various reuses. The sensor retained 85% activity after 18 months at 4 °C, confirming its long-term stability. Conclusions. This biosensor provides a cost-effective, sensitive, and reusable platform for sensitive HMIs detection in wastewater, offering an alternative to conventional analytical techniques.