Novel cysteic acid/reduced graphene oxide composite film modified electrode for the selective detection of trace silver ions in natural waters

Abstract

Novel cysteic acid/reduced graphene oxide composite film on a glassy carbon electrode has been prepared through the electrochemical oxidation of L-cysteine for silver sensing. Differential pulse anodic stripping voltammetry (DPASV) was employed for the detection of trace Ag(I) in aqueous solutions with the composite film modified electrode, which is referred to as an efficient method for the detection of trace heavy metals. We found the linear relationship between the peak current of the stripping voltammetry of Ag(I) and the concentration of Ag(I) in the range of 1.0 × 10⁻⁸ ∼ 2.0 × 10⁻⁴ M with a correlation coefficient R² = 0.996, and the detection limit can be down to 1.0 × 10⁻⁹ M (S/N = 3). The as-developed cysteic acid/reduced graphene oxide composite film modified electrode demonstrated ultrahigh sensitivity, reproducibility and recovery for the selective detection of trace Ag(I) without any interference from other metal ions.