A Microelectrode Sensor Chip for Detecting Mercury and Arsenic with Wide Concentration Ranges

Traditional detection methods such as atomic absorption spectroscopy offer high sensitivity and accuracy for heavy metal ion detection; however, they are often limited to laboratory environments due to bulky equipment and complex procedures. To meet the demand for rapid on-site detection, this study employs electrochemical analysis and utilizes Micro-Electro-Mechanical Systems (MEMS) technology to fabricate a microelectrode sensor chip for the electrochemical detection of heavy metal ions, Hg(II) and As(III). Nano-gold particles were electrodeposited on the sensing area of the working electrode of this chip using a constant-potential deposition method. Uniform distribution of the nanoparticles was obtained, which enhanced the effective specific surface area and electrochemical activity of the working electrode. Therefore, wide detection concentration ranges for Hg(II) of 5 to 1000 µg/L and for As(III) of 5 to 5000 µg/L were displayed, with detection limits of 1.4 µg/L and 2.4 µg/L, respectively. Moreover, the sensor exhibited satisfactory reproducibility, stability and anti-interference capability. These characteristics enable the developed microelectrode sensor chip to be utilized in the monitoring of a diverse range of pollution sources.