Synthesis and characterization of α-nickel (II) hydroxide particles on organic-inorganic matrix and its application in a sensitive electrochemical sensor for vitamin D determination

• The matrix of silica (SiO2) with graphene oxide (GO) physically incorporated.
• Amorphous Ni(OH)2 were directly prepared into the hybrid material SiO2/GO using N,N dimethylformamide.
• The modified electrode with hybrid material, SiO2/GO/Ni(OH)2 presented high sensitivity, allowing the determination of vitamin D3 in real sample beyond of presented low limit of detection.

This paper describes the synthesis, characterization and application of amorphous nickel (II) hydroxide particles, α-Ni(OH)2, onto a hybrid material composed of silica and graphene oxide, SiO2/GO. The sol-gel process using HF as the catalyst was used to obtain this organic-inorganic matrix. The Ni(OH)2 were prepared directly on the surface of the matrix using nickel (II) acetate and N,N-dimethylformamide (DMF) as a solvent. The SiO2/GO/Ni(OH)2 material was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. A glassy carbon electrode modified with the SiO2/GO/Ni(OH)2 material was used in the development of a sensitive electrochemical sensor for the determination of vitamin D3 by pulse differential voltammetry. A well-defined electro-oxidation peak of vitamin D3 was observed in sodium hydroxide at pH 13. The results indicated that the resultant SiO2/GO/Ni(OH)2 modified electrode is highly selective and very sensitive with a limit of detection, in pure laboratory solutions of 3.26 × 10−9 mol dm−3; therefore, it can be used to detect vitamin D3 in real samples.

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