Electrochemical Enantioanalysis of D- and L-Cysteine with a Dual-Template Molecularly Imprinted Sensor

The present work describes a faithful strategy of dual-template molecularly imprinted polymers (MIP) to chiral recognize and quantify D-Cystine (D-Cys) and L-Cystine (L-Cys) at ultra-trace level through "vector method." Briefly, one has to saturate association D-Cys while analyzes L-Cys, and vice versa. Herein, the working electrode, magnetic glassy carbon (MGCE), was initially drop-coated with molybdenum disulfide-ionic liquid (MoS2-IL) dispersion liquid for large specific surface area and excellent electrical conductivity. After the working electrode was dried naturally, chitosan (CS) was electrodeposited on. And the strong electrostatic interactions between CS and Fe[(CN)6]3−/4− could further enhance the electric signal. Next, dual-template MIP dispersion liquid was drop-coated on the working electrode. Moreover, Fe3O4 nano-particles (NPs) was regard as the support skeleton material of dual-template MIP, which could significantly improve the bonding strength with MGCE. Herein, the proposed sensor demonstrated good analytical figures of merits with Differential Pulse Voltammetry (DPV), showing that the LOD of L-Cys and D-Cys were 0.7402 pg ml−1 and 0.6136 pg ml−1 respectively, with linear response ranges from 1 pg ml−1 to 12 pg ml−1 for both enantiomers. Furthermore, the proposed sensor exhibited great potential in chiral recognition and biochemical analysis.