Analytical Sciences

Electrochemical Detection of Hydroxylamine via Au-Pt Alloy Nanoparticle-modified Single-walled Carbon Nanotube Electrodes

Yanfang GENG, Euna KO, Van-Khue TRAN, Woo Sung CHUNG, Chan Ho PARK, Min Ki KIM, Ga Hyun JIN, and Gi Hun SEONG

Department of Bionano Engineering, Hanyang University, Ansan, 425-791, South Korea

In the present study, we developed an electrochemical sensor for highly sensitive detection of hydroxylamine using Au-Pt alloy nanoparticles. Au-Pt alloy nanoparticles were electrochemically deposited on a working electrode made of single-walled carbon nanotubes. The framework composition in the Au-Pt alloy nanoparticle was easily controlled by adjusting the Au³⁺:Pt⁴⁺ composition ratio in the precursor solution. Morphological and chemical characterizations of the resulting Au-Pt alloy nanoparticles were performed using field emission scanning electron microscopy, X-ray diffraction, and energy dispersion X-ray spectroscopy. When the Au³⁺:Pt⁴⁺ ratio in the precursor solution was 1:5, the ratio of Au:Pt atom in alloy nanoparticle was about 6:4. Au₆₀Pt₄₀ alloy nanoparticles were found to have the optimum synthetic ratio for hydroxylamine detection. The electrocatalytic performance of Au-Pt alloy nanoparticles in the presence of hydroxylamine was also characterized using cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. In the chronoamperometric detection of hydroxylamine, the sensor exhibited a detection limit of 0.80 μM (S/N = 3) and a high sensitivity of 184 μA mM⁻¹ cm⁻². Moreover, the amperometric response of the sensor in 1 mM hydroxylamine was stable for a long time (450 s). Long-term stability tests showed that the current responses to hydroxylamine were 96, 91 and 85% of the initial signal value after storage for 5, 10, and 20 days, respectively.

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