Direct Quantification of Cd ²⁺ in the Presence of Cu ²⁺ by a Combination of Anodic Stripping Voltammetry Using a Bi-Film-Modified Glassy Carbon Electrode and an Artificial Neural Network

Abstract

In this study, a novel method based on a Bi/glassy carbon electrode (Bi/GCE) for quantitatively and directly detecting Cd ²⁺ in the presence of Cu ²⁺ without further electrode modifications by combining square-wave anodic stripping voltammetry (SWASV) and a back-propagation artificial neural network (BP-ANN) has been proposed. The influence of the Cu ²⁺ concentration on the stripping response to Cd ²⁺ was studied. In addition, the effect of the ferrocyanide concentration on the SWASV detection of Cd ²⁺ in the presence of Cu ²⁺ was investigated. A BP-ANN with two inputs and one output was used to establish the nonlinear relationship between the concentration of Cd ²⁺ and the stripping peak currents of Cu ²⁺ and Cd ²⁺. The factors affecting the SWASV detection of Cd ²⁺ and the key parameters of the BP-ANN were optimized. Moreover, the direct calibration model (i.e., adding 0.1 mM ferrocyanide before detection), the BP-ANN model and other prediction models were compared to verify the prediction performance of these models in terms of their mean absolute errors (MAEs), root mean square errors (RMSEs) and correlation coefficients. The BP-ANN model exhibited higher prediction accuracy than the direct calibration model and the other prediction models. Finally, the proposed method was used to detect Cd ²⁺ in soil samples with satisfactory results.