Electrogafting a p-Propylaniline/L-Cys Nanofilm onto a Glassy Carbon Electrode Resulting in Enhanced Electrosensing of Cd(II), Pb(II) and Hg(II)

Abstract

A glassy carbon electrode (GCE) was chemically modified with p-propylaniline/L–Cys molecules for the sensitivity determination of Cd(II), Pb(II) and Hg(II) in aqueous medium. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) characterized passivation of the electrode and 97.4% surface coverage with p-propylaniline/L–Cys molecules. Nanofilm coating was characterized by cyclic voltammetry (CV), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR) techniques to observe the surface morphology. The porous structure uniformly distributed thiol, amine and carboxylate groups throughout the coating to selectively coordinate and preconcentrate the three metal ions. Under the optimized conditions (deposition potential: ���� 1 V vs. SCE, deposition time: 90s), square wave anodic stripping voltammetry (SWASV) electroanalysis results indicated the linear increment of electrochemical signals with an increase in the concentration of Cd(II), Pb(II) and Hg(II) in range of 2.5 to 30 μgL���� 1. Based on the calibration plot, limit of detection (LOD, 3σ/m) are 0.103 μgL���� 1, 0.055 μgL���� 1 and 0.01 μgL���� 1 respectively. Analysis of drinking and tap water samples demonstrated precision and accuracy of the electrode as a prospective sensor for analysis of more complex aqueous environmental matrices.