Synthesis, Characterization, and Vitamin C Detection of a Novel L-Alanine-Modified PEDOT with Enhanced Chirality

A novel chiral L-alanine-modified 3,4-ethylenedioxythiophene (EDOT) precursor, (2S)-(2,3-dihydrothieno[3,4- b ][1,4]dioxin-2-yl)methyl 2-( tert -butoxy carbonylamino)propanoate (EDOT-Boc-Ala), was synthesized and electropolymerized in CH 2 Cl 2 –Bu 4 NBF. The corresponding polymer, poly((2S)-(2,3-dihydrothieno[3,4- b ][1,4]dioxin-2-yl)methyl 2-( tert -butoxy carbonylamino)propanoate) (PEDOT-Boc-Ala) film showed good redox activity and stability. The electrochemical behavior, structural characterization, chirality, solubility, spectroscopic properties, thermal stability, and morphology of PEDOT-Boc-Ala film were investigated. Both doped and dedoped PEDOT-Boc-Ala film could well dissolve in strong polar solvents such as dimethyl sulfoxide, tetrahydrofuran, and acetone, etc. The determination of specific rotation showed that the electropolymerization of EDOT-Boc-Ala did not influence its conformation and the polymer exhibited an enhanced specific rotation ([α] 20.0 = -191.08°) in comparison with that of the monomer ([α] 20.0 = -30.77°). Moreover, the amperometric biosensor based on PEDOT-Boc-Ala film (as immobilization matrix of biologically-active species) was successfully fabricated and employed to determine the concentration of vitamin C.