Guosong Chen

A New Electrochemical System Based on a Flow-Field Shaped Solid Electrode and 3D-Printed Thin-Layer Flow Cell: Detection of Pb2+ Ions by Continuous Flow Accumulation Square-Wave Anodic Stripping Voltammetry

Here we describe a new and sensitive flow electrochemical detection system that employs a novel flow-field shaped solid electrode (FFSSE). The system was constructed with a 3D-printed thin-layer flow cell (TLFC) and a flat screen-printed FFSSE with USB connection. This interface facilitates continuous flow accumulation square-wave anodic stripping voltammetry (ASV). The flow distribution in the working space of TLFC was simulated using the finite element method (FEM) and the shape and configuration of electrodes were optimized accordingly. We demonstrated the electrochemical determination of Pb2+ using this newly designed TLFC-FFSSE detection system without removal of oxygen from samples. This TLFC-FFSSE based system showed an attractive stripping voltammetric performance compared to a traditional ASV based method. A linear range for detection of Pb2+ was found to be 0.5-100 μg/L (0.5 to 100 ppb) and a detection limit of 0.2 μg/L (0.2 ppb) was achieved in the presence of bismuth as codeposition metal. The system was further applied to detect Pb2+ in biological broths of methane fermentation. The electrochemical detection results were consistent with that obtained from atomic fluorescence spectroscopy (AFS) analysis and the average recovery was found to be 95.5-106.5% using a standard addition method. This new flow electrochemical detection system showed better sensitivity and reproducibility compared to a traditional ASV based method. Such a system offers great potential for on-site and real-time detection of heavy metals where compact, inexpensive, robust, and low-volume analysis is required.

A Flow System for Detection of Cadmium Based on 3D-Printed Thin-Layer Cell and Flow-field Shaped Electrode

Abstract The concept of flow-field shaped (FFS) electrode was introduced for the first time and a FFS based three-electrodes system was built accordingly. Combined with a 3D-printed thin-layer flow cell (TLFC), a flow electrochemical system for detection of Cd2+ using square wave stripping voltammetry (SWSV) was thus constructed. Several factors that might affect the determination of Cd2+ were investigated, including the shape of the FFS electrode, the method of measurements, the buffer medium, the flow rate, and the deposition time. The results suggested this new detection system offered high sensitivity, good reproducibility, and great stability. Under the optimized conditions, the system showed a good linearity for detecting Cd2+ in the range of 2–100 μg L−1 with a correlation coefficient of 0.997, and a detection limit of 0.5 μg L−1 was achieved. Furthermore, the newly designed system was used to determine trace Cd2+ in environmental water samples and fermentation broths of biological methane. The results were consistent with that obtained with ICP-AES analysis and the recovery rates were found to be 90%–106%.