A magnetic CoFe2O4/SiO2 nanocomposite fabricated by the sol-gel method for electrocatalytic oxidation and determination of L-cysteine

Abstract

Magnetic CoFe2O4/SiO2 spinel-type nanocomposites have been fabricated by a sol-gel method in the presence of various acids. Their structural, morphological and magnetic properties were characterized by XRD, SEM, TEM, FTIR, VSM and EDX which revealed that they are formed in the presence of all precursors. TEM analysis indicates homogeneous and porous spherical morphology with nanosize grains 10–20 nm in diameter in the presence of salicylic acid. Electrochemical sensor application of nanocrystalline CoFe2O4/SiO2 synthesized by salicylic acid for determination of L-cysteine was investigated using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). DPV indicates that the sensor shows remarkable sensitivity for the determination of L-Cys. The response of a glassy carbon electrode modified with CoFe2O4/SiO2 is linear in the 0.02–425 μMLCys concentration range, with a 0.20 μMdetection limit (at an S/N ratio of 3). The electrode produces a negligible current response for tryptophan, glutamic acid and citric acid at the working potential applied (+0.748 V vs Ag/AgCl). The electrode is reliable, simple, rapidly prepared, precise, and the method does not require extensive sample treatment.