Low-cost potentiometric paper-based analytical device based on newly synthesized macrocyclic pyrido-pentapeptide derivatives as novel ionophores for point-of-care copper(<scp>ii</scp>) determination

A simple, cost-effective, portable and disposable paper-based analytical device is designed and fabricated for copper(II) determination. All solid-state ion-selective electrodes (ISEs) for copper and a Ag/AgCl reference electrode were constructed and optimized on the paper substrate. The copper electrodes were built using carbon nano-tube ink as a conductive substrate and an ion-to electron transducer. A suitable polymeric membrane is drop-cast on the surface of the conductive carbon ink window. The copper-sensing membrane is based on newly synthesized macrocyclic pyrido-pentapeptide derivatives as novel ionophores for copper detection. Under the optimized conditions, the presented all-solid-state paper-based Cu2+-ISEs showed a Nernstian response toward Cu2+ ions in 30 mM MES buffer, pH 7.0 over the linear range of 5.0 &#215; 10−7–1.0 &#215; 10−3 M with a limit of detection of 8.0 &#215; 10−8 M. The copper-based sensors exhibited rapid detection of Cu2+ ions with a short response time (