Sensitive detection of luteolin based on poly(diallyldimethylammonium chloride)-functionalized graphene-carbon nanotubes hybrid/beta-cyclodextrin composite film

Poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene sheets-multiwalled carbon nanotubes (G-CNTs) hybrid materials (PDDA-G-CNTs) were successfully synthesized. The materials were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. Then, an electrochemical sensor based on PDDA-G-CNTs/beta-cyclodextrin (PDDA-G-CNTs/beta-CD) was fabricated for the sensitive determination of luteolin. In 0.2 M HAc-NaAc buffer solution (pH 5.0), the redox peak currents of luteolin increased significantly on PDDA-G-CNTs/beta-CD modified glassy carbon electrode (GCE), suggesting that the composite film not only showed excellent electronic properties of PDDA-G-CNTs but also exhibited high molecular recognition capability of beta-CD. The chronocoulometry investigation demonstrated that the composite could effectively increase the electrochemical active surface. Under the optimal conditions, the oxidation peak current of luteolin increased linearly with increasing the concentration in the range from 0.05 to 60 mu M with the detection limit of 0.02 mu M (S/N = 3). The developed electrochemical sensor exhibited high selectivity, good stability and reproducibility, and also successfully determined luteolin in drug samples.