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A bismuth oxide-carboxylated multi-walled carbon nanotube/glassy carbon electrode (Bi 2 O 3 -CMWCNTs/GCE) was prepared for the detection of the flavonoid drug baicalein. The Bi 2 O 3 was grown on the surface of CMWCNTs by in-situ synthesis, and a simple, and efficient Bi 2 O 3 -CMWCNTs composite was prepared. The materials were characterized by XRD, SEM and EDS. CV and EIS techniques were used to study the electrochemical sensing performance of the composite electrode surface. The electrochemical performance and optimal detection conditions of baicalein on Bi 2 O 3 -CMWCNTs/GCE were investigated by LSV. The oxidation peak current of baicalein has a linear relationship with its concentration in the range of 0.01–15 μmol·L−1, with a detection limit of 2.0 nmol·L−1. The method is both stable and effective, and was successfully used for determination of baicalein in human urine and the Chinese herb Oroxylum indicum. It shows that the in situ synthesized materials have more stable characteristics, and have promising applications in the detection of flavonoid drugs. [Display omitted] • A novel sensor Bi 2 O 3 -CMWCNTs/GCE was prepared which for the stable determination of baicalein. • High selectivity, repeatability and reproducibility of the sensor were obtained. • Good linear concentration ranges of baicalein with low LOD (2.0 nM) were observed. • The sensor was successfully applied to the detection of baicalein in real samples. [ABSTRACT FROM AUTHOR]

In this paper, a sensitive electrochemical sensor based on MnO 2 nanoparticles functionalized carboxylated multi-walled carbon nanotubes (MnO 2 -c-MWCNTs) was prepared for the determination of curcumin. The synthesized materials have been fully characterized by instruments, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of curcumin on the MnO 2 -c-MWCNTs modified glassy carbon electrode (MnO 2 -c-MWCNTs/GCE) was investigated in detail by CV and chronocoulometry (CC). The electrochemical reaction mechanism of curcumin on the modified electrode was also discussed. In 0.1 M H 2 SO 4 solution, the peak current showed a good linear dependence on curcumin concentration in the range of 0.01–1 μM and 1–80 μM, The method has high sensitivity (3.30 μA μM−1 cm−1), and the detection limit is 6.0 nM. At the same time, the MnO 2 -c-MWCNTs/GCE has good anti-interference ability and stability. In addition, the sensor was used for the accurate and rapid determination of curcumin in commercial food samples, which shows its good potential for practical application. [Display omitted] • A novel sensor MnO 2 -c-MWCNTs/GCE was prepared which for the stable determination of curcumin. • High selectivity, repeatability and reproducibility of the sensor were obtained. • Good linear concentration ranges of 0.01–1 μM and 1–80 μM curcumin with low LOD (6.0 nM) were observed. • The sensor was successfully applied to the detection of curcumin in nanomolarity in real samples. [ABSTRACT FROM AUTHOR]