Innovative Use of Carbon Nanotubes in Electrochemical Sensors for the Analysis of Europium in Samples from the Environment

Abstract

An adsorptive stripping voltammetric method for the determination of trace europium(III) based on the adsorption of europium(III)−cupferron complex on the multiwall carbon nanotubes/spherical glassy carbon (MWCNTs/SGC) electrode modified with a lead film is presented. The method was optimized with respect to the main electrochemical parameters that affect the voltammetric determination (supporting electrolyte, pH, cupferron concentration, deposition potential and time). The calibration graph is linear from 5 × 10−9 to 5 × 10−7 mol l−1 with a correlation coefficient of 0.9993 for europium for a preconcentration time of 80 s. The detection limit for a preconcentration time of 80 s is as low as 1.3 × 10−9 mol l−1 for europium. To confirm the effectiveness of the developed procedure on the MWCNTs/SGC electrode, tests were also carried out on a glassy carbon electrode to compare the detection limits obtained. The developed procedure was tested for the effect of extraneous substances on the europium signal. The proposed method was successfully applied by studying natural samples and certified reference materials.