Green and facile solvent-free synthesis of NiTe2 nanocrystalline material applied to voltammetric determination of antioxidant morin

Abstract

Nanocrystalline nickel ditelluride, NiTe2, has been prepared mechanochemically using ball milling in an inert atmosphere at room temperature, starting from Ni34Te66 powder mixtures. Structural and microstructural characterization of the Ni34Te66 alloy was performed by X-ray powder diffraction analysis and transmission electron microscopy. The formation of a trigonal NiTe2 phase (with P-3 m1 symmetry) occurs along with 3 h, and the pure-phase sample with average crystallite size of about 18 nm is achieved with 6 h of milling. The nanocrystalline samples show a paramagnetic behavior at 2 K, with a magnetic moment decreasing at room temperature. The Ni34Te66 alloy containing 18 nm nanocrystallites of NiTe2 was applied in the construction of carbon paste electrodes to the voltammectric determination of morin, a phenolic and antioxidant compound present in red wines generally considered to act as UV protectant and free-radical scavenger. The electroanalytical response is linear from 0.014–32.0 μmol L−1 with a limit of detection of 0.0133 μmol L‒1 and a recovery range of 101–120 % (n = 3). The proposed sensor NiTe2/CPE was successfully applied to the determination of morin in high, medium and low polyphenols content red wines such as Tannat, Cabernet Sauvignon and Pinot Noir.