Characterization of cysteamine self assembled on gold functionalized with nitrilotriacetic acid and evaluation of copper(II) binding capacity with adsorption transfer stripping voltammetry

A self assembled monolayer of cysteamine was prepared on the surface of gold disc electrode and further modified with nitrilotriacetic acid. Modified electrode was characterized with cyclic voltammetry and electrochemical impedance spectroscopy in presence of potassium hexacyanoferrate(II)/(III). Thus prepared electrode was tested for determination of Cu2+ with adsorption transfer stripping voltammetry. The binding of Cu2+ onto the modified electrode was successfully performed for a wide range of tested concentrations. Electrode response (log Ip) was linearly proportional to −log c(Cu2+) with correlation coefficient R2 = 0.9759. The detection limit was 1·10-8M. The influence of interfering substances (Mg2+, Mn2+, Co2+, Ni2+ and Pb2+) was tested and it was found that Mg2+ and Pb2+ do not interfere while Mn2+, Co2+ and Ni2+ show slight interference. Real-world testing of copper content in urine samples confirmed practical application of prepared sensor.