Synthesis of novel chiral L-phenylalanine grafted PEDOT derivatives with electrochemical chiral sensor for 3,4-dihydroxyphenylalanine discrimination

Two amino-functionalized chiral poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives, poly(N-(tert-butoxycarbonyl)-L-phenylalayl (3,4-ethylenedioxythiophene-2'-yl)methylamide) (PEDOT-Boc-Phe) and poly(L-phenylalayl (3,4-ethylenedioxythiophene-2'-yl)methylamide) (PEDOT-Phe), were synthesized electrochemically via potentiostatic polymerization of corresponding monomers N-(tert-butoxycarbonyl)-L-phenylalayl (3,4-ethylenedioxythiophene-2'-yl)methylamide (EDOT-Boc-Phe) and L-phenylalayl (3,4-ethylenedioxythiophene-2'-yl)methylamide (EDOT-Phe). The electrochemical behavior, structural characterization, spectroscopic properties, and surface morphology of two chiral conducting polymer films were systematically explored. They displayed excellent reversible redox activities, and rough and compact surface. Importantly, PEDOT-Boc-Phe and PEDOT-Phe modified electrodes were used to identify 3,4-dihydroxyphenylalanine (DOPA) enantiomers by square wave voltammetry (SWV) in sulphuric acid solution. It is interesting that the SWV peak currents of enantiomers were found to be quite different and hence the enantiomers could be successfully recognized but the enantioselectivity was not observed using the common method of cyclic voltammetry (CV). Satisfactory results implied that the obtained polymer films could play crucial roles in the development of practical value and analytical application prospects.