2021 Volume 70 Issue 3 Pages 101-109
We developed carbon film-based electrodes by using an unbalanced magnetron (UBM) and an electron cyclotron resonance (ECR) sputtering equipment, and applied for the electroanalysis of four kinds of heavy metal ions: cadmium (Cd2+), lead (Pb2+), arsenic (As3+) and selenium (Se4+). Au nanoparticle embedded carbon (AuNP-C) film was formed by UBM co-sputtering. Regarding the detection of cadmium (Cd2+) and lead (Pb2+) ions, anodic stripping voltammetry measurement was performed with our carbon thin film electrode. The detection limits of Cd2+ and Pb2+ were 0.25 ppb and 1.0 ppb on our electrode. These values were better than those on the conventional GC electrode, also sufficient for the environmental analysis. On the other hand, the AuNP-C electrode was used for the detection of arsenic ions (As3+), which cannot be preconcentrated on the pure carbon electrode. A detection limit of 0.55 ppb was achieved, which is a sufficient performance for the environmental analysis. Reproducible results could be obtained for an As3+ measurement after Au was further electrodeposited on AuNPs because AuNPs are embedded in the carbon film, which prevented the AuNPs detaching from the electrode surface. In the case of selenium ion (Se4+) detection, an electrode in which Au was electrodeposited only on AuNPs at AuNP-C (Au/AuNP-C) electrodes was used because of the slow deposition rate of Se4+. Improved sensitivity and low detection limit were achieved compared with the electrode before the electrodeposition.