Mechanochemical synthesis of a Ni3-xTe2 nanocrystalline composite and its application for simultaneous electrochemical detection of dopamine and adrenaline

Abstract A novel electrochemical sensor CPE/Ni3-xTe2 (carbon paste electrode modified with nickel telluride) was constructed for the simultaneous detection of the neurotransmitters dopamine (DA) and adrenaline (AD) in phosphate buffer solution (pH 7.0). The composite containing Ni3-xTe2 and Ni nanocrystals was synthetized by mechanochemical synthesis using ball milling procedures in an inert atmosphere, starting from Ni75Te25 powder mixtures. The samples were processed from 3 h to 20 h and characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and magnetization. Rietveld analysis showed that Ni3-xTe2 and Ni nanocrystals have an average crystallite size of 10 nm and 4 nm, respectively, which was endorsed by transmission electron microscopy images and selected area electron diffraction data. The composite has ferromagnetic and superparamagnetic behavior governed by different sizes of the nanocrystalline Ni counterpart. The CPE/Ni3-xTe2 electrode showed electrocatalytic properties towards DA and AD with two separated peaks. The linear response range for the determination of both DA and AD was 4–31 μmol L−1 and the detection limits (S/N = 3) were 0.15 μmol L−1 and 0.35 μmol L−1 for DA and AD, respectively. Repeatability and stability studies are also provided to evaluate the applicability of a modified electrode. Hence, the CPE/Ni3-xTe2 represents a promising electrochemical platform for DA and AD quantification in various kinds of matrices, with preparation and operation routes totally based on green chemistry principles.