Electrocatalytic oxidation and differential pulse voltammetric determination of using a carbon nanotubes modified electrode

Flow injection amperometric sensing of hydroxylamine at a Cu(ii)–neocuproine-functionalized multiwalled carbon nanotube/screen printed carbon electrode

In the electrocatalytic oxidation mechanism of NH₂OH at modified electrode, firstly NH₂OH reacted with [Cu(Ncp)₂]²⁺ and oxidized to N₂O. The formed [Cu(Ncp)₂]⁺ was reoxidized by giving electrons to electrode resulting in enhancement of anodic current.

Fabrication of Highly Sensitive and Stable Hydroxylamine Electrochemical Sensor Based on Gold Nanoparticles and Metal-Metalloporphyrin Framework Modified Electrode

This paper describes the immobilization of gold nanoparticles on metal-metalloporphyrin frameworks (AuNPs/MMPF-6(Fe)) through electrostatic adsorption. The composites were characterized by powder X-ray diffraction, zeta potential, transmission electron microscopy, electrochemical impedance spectroscopy, and voltammetric methods. MMPF-6(Fe) exhibited a pair of redox peaks of the Fe(III)TCPP/Fe(II)TCPP redox couple. The AuNPs/MMPF-6(Fe)-based electrochemical sensor demonstrates a distinctly higher electrocatalytic response to the oxidation of hydroxylamine due to the synergic effect of the gold metal nanoparticles and metal-metalloporphyrin matrix. The voltammetric current response exhibits two linear dynamic ranges, 0.01-1.0 and 1.0-20.0 μmol L(-1), and the detection limit was as low as 0.004 μmol L(-1) (S/N = 3). Moreover, the biosensor exhibits high reproducibility and stability in acid solution. Our work not only offers a simple way to achieve the direct electrochemical behavior of metalloporphyrin but also expands the potential applications of MOFs-based composites in bioanalysis.