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 a 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 decreased more than 110 mV. The enhanced oxidation signal of Tyr at the modified electrode is attributed to the improved electron transfer rate at these nanoparticles and enhanced 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 correlated to Tyr concentration in the range from 0.8-300.0 μM, and the detection limit calculated was 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.