Electrochemical detection of copper in water using carbon paste electrodes prepared from bio-template (grapefruit peels) functionalized with carboxyl groups

The present work shows the preparation of a novel material to be used as an electrode in the detection of copper in solution. The material has been prepared using grapefruit peels as a bio-template which have been functionalized with carboxyl groups. The surface chemistry of the material was characterized, as well as its physical properties, and the results were related to copper adsorption studies in solution to obtain information on the mechanism of pre-concentration and detection of the metal. The detection of the metal was made by differential pulse voltammetry, from the peak current the calibration curve of the device was constructed, which showed a detection limit of 2.5μgL−1, quantification limit of 15μgL−1 and a line range of 15 to 65μgL−1, R=0.996. The statistical analysis of the regression showed a standard error of the estimated values of 0.083, demonstrating the accuracy of the calibration curve obtained. Furthermore, the statistical data showed that all the experimental data obtained are within a confidence level of 0.95, evidencing a good reproducibility of the analysis, showing the feasibility of using the proposed material as an electrode to be used in a mobile device for detection of metal. [Display omitted] •A novel sensor for Cu detection was prepared from grapefruit peels.•Detection limit of 2.5μgL−1 was obtained using DPV electrochemical studies.•Detection metal mechanism is due interactions between Cu and carboxylic groups.•Simple operation, low cost, high sensitivity and good reproducibility were obtained.