Electroanalysis of Amino Acid Tyrosine by an Electrochemical Sensor Modified by Strontium Ferrite Nanostructure

An electrochemical sensor was fabricated by strontium ferrite (SrFe) nanostructure modified carbon paste electrode (SrFeME). This electrode showed good catalytic effect on oxidation of amino acid tyrosine (Tyr) in voltammetric studies. It can improve the anodic peak current of Tyr significantly and also decrease the oxidation overpotential of this amino acid. The peak current increased by two times and the overpotential is decreased more than 110 mV. The enhancing of oxidation signal of Tyr at modified electrode is related to the improving the electron transfer rate at these nanoparticles and increasing the active surface area of the modified electrode by the nanoparticles. This electrode was used as an electrochemical sensor for the measurement of Tyr by differential pulse voltammetry. The anodic peak current was linearly related to Tyr concentration in the range from 0.8 μM to 300.0 μM and the detection limit was calculated as 0.15 μM (S/N = 3). The presence of ascorbic acid, dopamine, glucose and a number of ions could not affect the Tyr measurement. Finally, the proposed sensor was successfully used for measurement of Tyr in real samples.