A novel electrochemical sensor based on N, S co-doped liquorice carbon/functionalized MWCNTs nanocomposites for simultaneous detection of licochalcone A and liquiritin.

In this study, nanoporous C was prepared from the roots, stems and leaves of liquorice and modified via element doping. Then, the nitrogen and sulfur co-doped liquorice carbon (N, S-LC) and functional multiwall carbon nanotubes (f-MWCNTs) were dispersed using an ultrasonic dispersion technology, and a binary nanocomposite was prepared. N, S-LC plays a key role in the formation and electrochemical efficiency of binary nanocomposites, and electrochemical impedance spectroscopy indicates that the binary complexes formed by the hybridisation of N, S-LC and f-MWCNTs can improve the electron transfer ability of an electrode. The electrochemical behaviour of Licochalcone A (LicA) and Liquiritin (LQ) on GCE modified by N, S-LC/f-MWCNTs binary nanocomposite was investigated via differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The interpeak potential difference between LicA and LQ were 0.48 V. The calibration curves for LicA and LQ were obtained in the range of 0.4-70.0 μM and 0.1-150.0 μM, respectively, and the detection limits are 33 and 25 nM (S/N=3), respectively. The modified electrode has been successfully applied to the simultaneous determination of LicA and LQ in licorice with satisfactory recoveries as confirmed by HPLC method.