An electrochemical sensor based on green tea extract for detection of Cd(II) ions by differential pulse anodic stripping voltammetry

Abstract

In this study, a simple, selective and inexpensive electrochemical sensor was developed to detect Cd(II) ions. To this end, the bioextract (BioExt) obtained by ethanol extraction of dry green tea leaves was decorated with functionalized carbon nanotubes (MWCNTs), and the obtained nanobiocomposite (BioExt/MWCNTs) was immobilized to the glassy carbon electrode (GCE) surface. X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry (CV) characterizations were applied. Differential pulse anodic stripping voltammetry (DPASV) was preferred for the quantification of Cd(II) ions on GCE modified with BioExt/MWCNTs nanobiocomposite (BioExt/MWCNTs/GCE). Under optimal conditions, the peak currents depending on the Cd(II) ions concentrations on the BioExt/MWCNTs/GCE surface showed linearity between the range of 0.05 ~ 6.0 µM and the correlation coefficient (R2) was calculated as 0.9333, and the detection limit (LOD) as 1.01 nM. The proposed nanobiostructured-sensor (BioExt/MWCNTs/GCE) showed long-term stability, high selectivity, improved voltammetric behavior and good reproducibility. Cd(II) ions were successfully detected and quantified in both river and drinking water samples with this proposed nanobiostructured sensor using the standard addition method. It was observed that electrochemically obtained results were consistent with the results obtained with ICP-MS, which is a spectrometric comparison method.