Analytical Sciences

Novel Nitrite Sensing Using a Palladium-polyphenosafranine Nano-composite

Xiaohong ZHU and Xiangqin LIN

Department of Chemistry, University of Science and Technology of China, Hefei 230026, P. R. China

A novel palladium-polyphenosafranine nano-composite (PPS-Pd) was synthesized by electrochemical co-deposition at a glassy carbon electrode (GCE) for fabrication of a nitrite sensor, PPS-Pd/GCE. This PPS-Pd film was characterized by X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microanalysis (SEM). It was found that the PPS-Pd nano-composite consisted of Pd nanoparticles smaller than 10 nm in diameter which stick together due to the polymer, forming a Pd-embedded PPS layer structure. The sensing ability was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and differential pulse amperometry (DPA). The PPS-Pd/GCE had excellent catalytic activity toward the oxidation of nitrite: high current sensitivity of 0.365 A/M cm^-2, good reproducibility, good stability and fast response. In neutral solutions, a linear concentration range of 1.0 × 10^-6 to 1.1 × 10^-3 M (R² = 0.999) with the detection limit (s/n = 3) of 3 × 10^-7 M nitrite was obtained for DPV determination.

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