Effect of the sp(2)/sp(3) Ratio in a Hybrid Nanocarbon Thin Film Electrode for Anodic Stripping Voltammetry Fabricated by Unbalanced Magnetron Sputtering Equipment.

Hiroyuki Yanagisawa, Ryoji Kurita, Tomoyuki Kamata, Kyoko Yoshioka, Dai Kato, Ayumi Iwasawa, Tetsuya Nakazato, Masaki Torimura, Osamu Niwa

Index: Anal. Sci. 31 , 635-41, (2015)

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Abstract

The effect of the sp(2)/sp(3) ratio in an unbalanced magnetron sputtered nanocarbon film electrode was studied for determining Cd(2+) and Pb(2+) by anodic stripping voltammetry (ASV). The signal-to-noise ratio in the ASV measurement improved as the sp(3) concentration in the carbon film increased because the noise current decreased with the increasing sp(3) concentration. The detection limits with a carbon film containing 50% sp(3) were 0.25 and 1.0 μg L(-1) for Cd(2+) and Pb(2+) with high repeatability (Cd: 4.6% and Pb: 6.4%, n = 3). For a real sample measurement, a pretreatment system combining a photooxidation reactor and a cation exchange column was used to eliminate the interference from EDTA and Cu(2+), which forms a stable complex or alloy with Cd(2+) and Pb(2+). More than 99% of the interference was eliminated, and accurate signal currents for Cd(2+) and Pb(2+) were successfully obtained with the pretreatment system.