A Disposable Copper (II) Ion Biosensor Based on Self-Assembly of L-Cysteine on Gold Nanoparticle-Modified Screen-Printed Carbon Electrode

A disposable copper (II) ion biosensor based on self-assembly of L-cysteine on gold nanoparticle-modified screen-printed carbon electrode was fabricated. The electrode was modified by attaching gold nanoparticles onto the surface of screen-printed carbon electrode through seed mediated growth method followed by self-assembly of L-cysteine. As demonstrated by differential pulse voltammetry, the sensor exhibited high sensitivity to copper (II) ion down to ppb (parts per billion) levels. Optimization of various experimental parameters such as pH, buffer concentration, and preconcentration time, which influenced the performance of the biosensor, was investigated. The sensor demonstrated a wide linear response range from 10 to 0.005 ppm (r = 0.9870), with a lower detection limit of 8 ppb using 10min of preconcentration time. The sensor based on screen-printed electrode provides a cost-effective means of application of copper ion sensor for the detection of ppb level of copper ions in water.