Rapid detection of trace Cu using an l-cysteine based interdigitated electrode sensor integrated with AC electrokinetic enrichment.

Copper is an indispensable trace element for human health. Too much or too little intake of copper ion (Cu ) can lead to its own adverse health conditions. Therefore, detection of Cu is always of vital importance. In this work, a simple sensor was developed for rapid detection of trace Cu in water, in which L-cysteine (Cys) as a molecular probe was self-assembled on a gold interdigital electrode to form a monolayer for specific capture of Cu . The interfacial capacitance of interdigital electrode was detected to indicate the target adsorption level under an AC signal working as the excitation to induce directed movement and enrichment of Cu to the electrode surface. This sensor reached a limit of detection of 4.14 fM and a satisfactory selectivity against eight other ions (Zn , Hg , Pb , Cd , Mg , Fe , As , and As ). Testing of spiked tap water was also performed, demonstrating the sensor's usability. This sensor as well as the detection method shows a great application potential in fields such as environmental monitoring and medical diagnosis.