Study Of Chiral Electrochemical Sensors Based On Amino Acid And Derivatives

The study of chirality has a very important research value and significance in many fields,such as medicine and chemical industry that chiral molecules are of the most essential in nature.Amino acids are the basic unit in life structure and the precursors of chiral drugs.However,it is not only beneficial for the study of basic subjects to carry out chiral recognition,but also can greatly promote the development of bio-pharmaceutical field and other blank areas.Electrochemical chiral sensors have been widely used in many fields for the advantages such as simple operation,high speed and high sensitivity.In this paper,the amino acid modified electrode was used to modify the amino acids or other chiral analytes onto the electrode surface by electrochemical means which form large steric hindrance but they maintain the ability of chiral selectors.In this paper,amino acid modified electrode was used to identify theenantiomers of lysine enantiomers,ascorbic acid enantiomers and phenylalanine.In order to structure a simple,fast,cost-effective,real-time chiral recognition sensor is to be used in practical chemical engineering.The main research contents are as follows.Firstly,L-glutamic acid was used as chiral selector,and the L-Glu/GCE modified electrode was used for chiral recognition by cyclic voltammetry(CV)on the surface of glassy carbon electrode(GCE)in order to formL-Glu/GCE modified electrode for chiral recognition.The peak current difference(?I)was measured by cyclic voltammetry(CV)and differential pulse voltammetry(DPV),which could be used to realize the electrochemical recognition of L-lysine/D-lysine.Then the effects of reaction time,lysine concentration and pH on chiral recognition were discussed.However,the electrochemical sensor was used to detect and analyze the mixed solution of L-lysine /D-lysine that the peak current was linearly correlated with the increase of the content of L-lysine so that the sensor can be used to detect the proportion of single configuration in the enantiomers.In order to further explore the mechanism of modified electrode for chiral recognition,we make further efforts to investigat the recognition of ascorbic acid by L-Cysteine.However,we prepared L-Cys/GCE modified electrode for chiral recognition of ascorbic acid.The electrochemical detection showed that the electrode had good chiral recognition ability and high sensitivity to ascorbic acid.Based on the three points above principal and the different structures of chiral enantiomers,the different structure of the chiral enantiomers.AA could interact with L-Cysteine compact through the force of hydrogen bond,however,the IAA could not produce a force of intermolecule because of the steric hindrance.Then,the effect of ascorbic acid concentration and the pH on chiral recognition were discussed.The sensor can be used to analyze and detect the content of a certain configuration of ascorbic acid enantiomers after gain the best detection condition.Therefore,the detection time is short and the recognition efficiency is high,which is helpful to further explain the electrochemical chiral recognition principles.In order to further improve the efficiency of electrochemical chiral recognition,and explore the influence of the structure of the adverse that we used N-acetyl-L-Cysteine as the chiral selector to identify the enantiomers of alanine and ascorbic acid.However,compared with the difference in chiral discrimination of AA/IAA enantiomers between L-Cys and the NAC,we find that the recognition effect of NAC/GCE modified electrodeis was more obvious than L-Cys/GCE.Compared with L-Cys and N-acetyl-L-Cys,the N-acetyl-L-Cys exhibited a unique structure and enhanced hydrophility due to the expanded internal spaces among the macromolecular chains and exposed polar functional groups during amidation.It is concluded that the structure and properties of chiral selectors and chiral enantiomers played an important role in chiral recognition.