A Chiral Voltammetric Sensor Based on a Paste Electrode Modified by Cyanuric Acid for the Recognition and Determination of Tyrosine Enantiomers

An enantioselective voltammetric sensor based on graphitized carbon black (Carboblack C) paste electrode modified by cyanuric acid (CA) was developed for the selective recognition and determination of tyrosine (Tyr) enantiomers. The sensor preferably recognizes D-Tyr because of steric differences between the Tyr enantiomers and nanocavities of CA supramolecules. Using cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and polarimetry, the conditions for modifying Carboblack C with cyanuric acid were optimized and the electrochemical characteristics of the sensor and the conditions for recording voltammograms were studied. The performance of the sensor was estimated under the conditions of differential pulse voltammetry. The proposed sensor was used to recognize and determine the L- and D-enantiomers of tyrosine in a mixture and in samples of urine and human blood plasma. Using molecular dynamics simulation, the features of the interaction of tyrosine enantiomers with CA supramolecules are considered.