Simultaneous Determination Of Two Flavonoids Based On Disulfide Linked Beta-Cyclodextrin Dimer And Pd Cluster Functionalized Graphene-Modified Electrode

In the present work, ultrafine Pd clusters with a uniform size of similar to 2.0 nm were monodispersed on the surface of reduced graphene oxide (RGO) using a clean and green approach in the absence of additional reductants and surfactants. Disulfide linked beta-cyclodextrin dimer (SS-beta-CD) was non-covalently bonded to the surface of Pd@RGO. By combining the merits of Pd@RGO and the SS-beta-CD, a highly sensitive electrochemical sensing platform was developed based on the SS-beta-CD-Pd@RGO nanohybrids. Simultaneous electrochemical detection of baicalin and luteolin using a SS-beta-CD-Pd@RGO nanohybrid-modified electrode is described for the first time. The SS-beta-CD showed a higher supramolecular recognition capability than the native beta-CD, which may be caused by the cooperative binding abilities of two adjacent CD units. Due to the synergistic effects from the Pd@RGO (e.g. good electrochemical properties and large surface area) and SS-beta-CD (e.g. hydrophilic external surface, high supramolecular recognition, and good enrichment capability), the SS-beta-CD-Pd@RGO modified electrode was found to have linear response ranges of 0.02-20.00 mu M for baicalin and 0.01-10.00 mu M for luteolin with relatively low detection limits of 0.0052 mu M for baicalin and 0.0070 mu M for luteolin. The results indicated that SS-beta- CD-Pd@RGO nanohybrids are excellent sensing materials for the electrochemical determination of flavonoids. The proposed method could be successfully utilized to detect baicalin and luteolin in serum samples, and has a promising application in practice.