Ultrasensitive electrochemical sensor based on CdTe quantum dots-decorated poly(diallyldimethylammonium chloride)-functionalized graphene nanocomposite modified glassy carbon electrode for the determination of puerarin in biological samples

In the present study, a CdTe quantum dot (QD)-decorated poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene (CdTe-PDDA-Gr) nanocomposite was synthesized via a simple one-step chemical reduction of exfoliated graphite oxides in the presence of PDDA and CdTe QDs. Characterization of as-prepared nanocomposite using transmission electron microscopy (TEM) and x-ray diffraction (XRD) clearly demonstrate the successful attachment of PDDA and CdTe QDs to the Gr sheets. The CdTe-PDDA-Gr showed an ultrafast electron transfer property and a strong absorption effect for puerarin and thus yields excellent electrocatalytic activity towards the oxidation of puerarin. Differential pulse voltammetry (DPV) was applied for the determination of puerarin, a good linear relationship of the oxidation peak current and the concentrations of puerarin in the range of 0.001 to 1.0 mu M was achieved. The detection limit was 0.6 nM (SNR of 3) which was comparable with that of liquid chromatography-mass spectrometry (LC-MS). The proposed method was successfully applied for the determination of puerarin in human plasma and pharmaceutical injections with good recoveries. (C) 2015 Elsevier Ltd. All rights reserved.