Voltammetric food analytical sensor for determining vanillin based on amplified NiFe2O4 nanoparticle/ionic liquid sensor

Abstract

We describe a powerful type of vanillin electrochemical sensor based on a carbon paste electrode (CPE) modified with NiFe2O4 nanoparticle and 1-hexyl-3-methylimidazolium chloride (1H3MCl). The NiFe2O4 nanoparticle was synthesized by co-precipitation strategy and characterized by FESEM, XRD, and EDAX methods. The results revealed a spherical shape NiFe2O4 nanoparticle with diameter ~ 22 nm. The oxidation peak of vanillin was recorded at potentials + 690 and + 650 mV at the surface of CPE and NiFe2O4/1H3MCl/CPE by cyclic voltammetric method, respectively. The NiFe2O4/1H3MCl/CPE exhibited high electro-catalytic ability toward vanillin electro-oxidation and indicated two separated oxidation signals at potentials 640 and 1050 mV for vanillin and tryptophan by differential pulse voltammetric method. The sensitivity 0.1011 and 0.5058 μA µM−1 as well as the detection limits 1.0 nM and 0.09 µM were observed for determination of vanillin and tryptophan at the surface of NiFe2O4/1H3MCl/CPE, respectively. The NiFe2O4/1H3MCl/CPE was used as a food analytical sensor for determining vanillin and tryptophan in food samples such as coffee milk, chocolate, and biscuit.