Drop-coated molybdenum disulfide-ionic liquid for improving the electrochemical chiral recognition ability of chitosan

Abstract A faithful strategy to significantly improve the enantiorecognition ability of chitosan (CS) is proposed via drop-coating molybdenum disulfide (MoS2)-ionic liquid (IL) nanocomposite. The present work describes a novel, simple, and effective chiral interface based on MoS2-IL/CS nanocomposite which was elaborately integrated to combine the electrical signal amplification and space complexity of MoS2-IL and vast enantiorecognition sites of CS for the electrochemical enantiorecognition of tryptophan (Trp) enantiomers. Differential pulse voltammetry (DPV) was adopted to evaluate the potential differences (ΔEP) between the oxidation peaks of L-Trp and D-Trp. MoS2-IL/CS nanocomposite showed higher chiral recognition ability result from spatial asymmetry of MoS2-IL/CS. Herein, several parameters, such as drop-coated volume and concentration of MoS2-IL, electrodeposited viscosity, time and temperature of CS, detection temperature and pH were optimized in order to obtain a large ΔEP signal between L-Trp and D-Trp, and the ΔEP value can reach 53.3mV under optimal conditions. Furthermore, different percentages of Trp mixtures and DPV peaks potential were detected with a good linear relationship even in the real sample, which indicated that MoS2-IL/CS chiral interface could effectively quantify the enantiomer excess (ee) of Trp enantiomers in Trp mixtures.