2021

Morris, Adam; Serrano, Núria; Díaz-Cruz, José Manuel; Bendavid, Avi; Chen, Miao; Vepsäläinen, Mikko

<p>In this paper, a vibrating boron-doped diamond (BDD) electrode electroanalytical device and respective method for the analysis of ultralow concentrations of Cd(II) in water were studied. The enhanced mass transfer on the electrode surface was studied using Ru(NH₃)₆Cl₃. Vibration with 133 Hz frequency enhanced the Ru(III) to Ru(II) reduction by 92.6% compared to a static electrode. The peak current of the anodic stripping voltammetry (ASV) method employed was increased by a factor of 5.3 and 4.7 for 10 and 30 µg L⁻¹ Cd(II) concentrations, respectively, when a frequency of 200 Hz was used. A calibration plot with two linear regions was resolved between 0.01 and 1 µg L⁻¹ and 1–30 µg L⁻¹ with the LOD and LOQ of 0.04 µg L⁻¹ and 0.12 µg L⁻¹, respectively. The applicability of the device and the respective method in the analysis of real environmental samples was successfully verified by analysis of river samples and comparing the results with the ICP analysis presenting high reproducibility and trueness. According to the results of this research, the vibrating BDD electrode with the ASV method has excellent analytical performance without surface modification or regular replacement or polishing of the electrode surface. Combining the exceptional electrochemical and chemical properties of BDD with enhanced mass transfer and signal strength of vibrating electrodes makes the system especially suitable for on-site and online analysis of heavy metals.</p>