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

Abstract

A faithful and facile strategy to significantly improve the electrochemical chiral recognition ability of chitosan is proposed via drop-coating molybdenum disulfide-ionic liquid (MoS 2 -IL) nanocomposite. • MoS 2 -IL was first used to improve the enantiorecognition ability of CS. • There is a good linear relationship between the DPV peak potential and ee. • The proposed sensor exhibited satisfactory reproducibility and stability. • The proposed sensor exhibited enantiorecognition ability for other enantiomers. A faithful strategy to significantly improve the enantiorecognition ability of chitosan (CS) is proposed via drop-coating molybdenum disulfide (MoS 2 )-ionic liquid (IL) nanocomposite. The present work describes a novel, simple, and effective chiral interface based on MoS 2 -IL/CS nanocomposite which was elaborately integrated to combine the electrical signal amplification and space complexity of MoS 2 -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 (ΔE P ) between the oxidation peaks of l -Trp and d -Trp. MoS 2 -IL/CS nanocomposite showed higher chiral recognition ability result from spatial asymmetry of MoS 2 -IL/CS. Herein, several parameters, such as drop-coated volume and concentration of MoS 2 -IL, electrodeposited viscosity, time and temperature of CS, detection temperature and pH were optimized in order to obtain a large ΔE P signal between l -Trp and d -Trp, and the ΔE P value can reach 53.3 mV 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 MoS 2 -IL/CS chiral interface could effectively quantify the enantiomer excess (ee) of Trp enantiomers in Trp mixtures.