A chiral sensor for recognition of DOPA enantiomers based on immobilization of β-cyclodextrin onto the carbon nanotube-ionic liquid nanocomposite

A sensitive electrochemical method was explored for chiral recognition of 3,4-dihydroxyphenylalanine (DOPA) enantiomers based on immobilization of β -cyclodextrin ( β -CD) onto the nanocomposite comprising multiwalled carbon nanotubes (MWCNTs) and ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (BIMIMPF 6 ) modified glassy carbon electrode ( β -CD/MWCNTs-IL/GCE). The combination of ionic liquid and carbon nanotubes could create unique nanomaterials which facilitated the electron transfer. In addition, β -CD was brought in to act as the chiral selector for DOPA enantiomers recognition. The immobilization process of β -CD/MWCNTs-IL/GCE was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The chiral interface ( β -CD/MWCNTs-IL/GCE) was employed to discriminate DOPA enantiomers via differential pulse voltammetry. The results indicated that the proposed sensor exhibited a stronger electrochemical response toward D-DOPA over the linear range from 4.0 × 10 −3 to 4.0 × 10 −9  mol L −1 and the detection limit was 1.2 × 10 −9  mol L −1 (S/N = 3). This work provided an available platform for enantioselective recognition of DOPA enantiomers based on the nanocomposite.