Potentiometric Sensor for Trace Level Analysis of Copper Based on Carbon Paste Electrode Modified With Multi-walled Carbon Nanotubes

It is here established that potentiometric carbon paste electrodes (CPE) modified with multi walled carbon nanotubes (MWCNT) are useful analytical tools for copper ion determinations. MWCNTs are incorporated into the composition of CPE to decrease the ohmic resistance. The selectivity of CPE is modified by applying the copper(II) ionophore I as recognition element. To optimize the method, sensor response is evaluated by changing the CPE composition and pH of the sample solution. The suitable selectivity coefficient is obtained for the CPEs compare to interfering cation. The Nernstian slope and detection limit are achieved 28.4 mV/decade and 1.1x10(-6) M Cu2+, respectively. The electrode shows a wide dynamic linear range for Cu2+ from 10(-6) to 10(-2) M. The sensor displays a short response time of 1.05 s. Finally, a number of native and spiked drinking water samples are potentiometrically assessed for copper and the results compared with atomic absorption spectroscopy (AAS). The result of presented sensor is in agreement with the result of AAS for acidified sample solution.