Electrochemical sensor for the detection of ppq-level Cd2+ based on a multifunctional composite material by fast scan voltammetry

Abstract

Herein, an electrochemical sensor for highly sensitive and selective detection of cadmium ion (Cd2+) based on a multifunctional composite material [email protected]3O4 was developed by fast scan voltammetry (FSV). The multifunctional composite material could selectively and completely adsorb Cd2+ in the sample to achieve pre-enrichment, followed by combination with the electrode surface by magnetic force to form an electrochemical sensor in only one step. In addition, its good electrical conductivity made Cd2+ adsorbed at the electrode/solution interface existing in an adsorption state. In this case, FSV was used to make the response current increase linearly with the scan rate and thus then greatly improve the detection sensitivity. In addition to selective adsorbent 1-Aza-15-crown-5 ether, masking agent NaSCN was also used to achieve dual selection. Under the optimal conditions obtained by orthogonal experiment, Cd2+ in the concentration range of 0.1 ng L−1–2 ng L−1 could be detected by FSV at 400 V s-1. The limit of detection (LOD) was 30 parts per quadrillion (ppq). Stability, selectivity and reusability were satisfactory, and good accuracy and precision were obtained in the detection of actual samples. Therefore, this simple, sensitive, selective and accurate method for Cd2+ testing is promising in on-site environmental monitoring.