title: Au Nanoparticle-Embedded Carbon Films for Electrochemical As(3+) Detection with High Sensitivity and Stability.
abstract: Au nanoparticle (AuNP)-embedded carbon films were formed with a one-step reproducible process by using unbalanced magnetron (UBM) cosputtering to make it possible to detect As(3+) in water. The sputtered Au components formed NPs (typically 5 nm in diameter) spontaneously in the carbon films, owing to the poor intermiscibility of Au with carbon. The surface contents of embedded AuNPs in the carbon film were widely controllable (Au = 13-21 at %) by regulating the target powers of Au and carbon individually. The obtained film had a flat surface (Ra = 0.1 nm) despite the fact the AuNPs were partially exposed at the surface. By anodic stripping voltammetry (ASV) As(3+) detection, a limit of detection of 0.55 ppb and linear dynamic range of 1-100 ppb were obtained with our electrode. These values meet the requirements imposed by international regulation. Moreover, our electrode structure realized good electrode stability for repetitive ASV measurements (relative standard deviation (RSD) = 11.7%, n = 15) because the partially embedded AuNP structures prevented the AuNPs from detaching from the surface. This result was achieved by the electrode recovery only by a potential scan from 0.1 to 1.5 V. Our electrodes can be stocked for a long time (2 years) with maintaining the electrode performance, which is very attractive for practical electrode. Selectivity test by using Tsukuba tap water added 10 ppb As(3+) and 1000 ppb Cu(2+) was successfully achieved with existence of 0.1 M EDTA (RSD = 2.6%, n = 3). The ASV results with tap water samples agreed well with those by the conventional ICPMS method.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba 305-8566, Japan.|Institute of Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Kato
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba 305-8566, Japan.|Chiba Institute of Technology , 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kamata
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba 305-8566, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Kato
authors.affiliation: Institute of Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yanagisawa
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba 305-8566, Japan.|Saitama Institute of Technology , 1690 Fusaiji, Fukaya, Saitama 369-0293, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Niwa