A novel electrochemical chiral interface based on the synergistic effect of polysaccharides for the recognition of tyrosine enantiomers

Electrochemical chiral interface based on two polysaccharides, soluble starch (SS) and chitosan (CS), was fabricated and used for chiral recognition of tyrosine (Tyr) enantiomers via square wave voltammetry (SWV). The SS-CS composite was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) method. Under the optimized experimental conditions, the oxidation peak current ratio of L-Tyr to D-Tyr (I-L/I-D) and the difference between the peak potential (Delta Ep = E-D - E-L) were observed to be 1.38 and 12 mV at the SS-CS/GCE. In addition, a good linear relationship between Tyr enantiomer concentration and peak current could be observed. The SS-CS/GCE exhibited good coefficients of determination (R-D-Tyr(2) = 0.99631 and R-L-Tyr(2) = 0.98333) for D-Tyr and L-Tyr in the concentration range 0.01-1.00 mM. The novel SS-CS/GCE showed an ability to predict the ratios of L- and D-Tyr in a racemic mixture and exhibited the possibility of qualitative and quantitative determination of Tyr enantiomers. The proposed SS-CS/GCE-based chiral sensor exhibited high anti-interference ability in the presence of 10-fold higher concentrations of physiological substances and various metal compounds. Meanwhile, the SS-CS/GCE possessed good repeatability and excellent reproducibility.