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• The MoO 3 -PEDOT nanomaterials were prepared by in-situ growth method. • CD-MOF was electrodeposited on the MoO 3 -PEDOT/GCE to form a luteolin electrochemical sensor with outstanding performances. • The sensor was successfully applied for detecting luteolin in both homemade and commercial chrysanthemum tea. Chrysanthemum tea is a tranditional Chinese health drink, which contains luteolin, a flavonoid with vesatile health benefit activities. Herein, A sensitive electrochemical sensor based on composite materials consisting of MoO 3 nanorods, poly (3, 4-ethylene dioxyethiophene)(PEDOT), and γ -cyclodextrin metal–organic framework(CD-MOF) was prepared.The materials were characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Due to the synergistic effects of the materials, the sensor showed a wide linear range of 0.4 nM −1800 nM and a low detection limit (LOD) of 0.1 nM (S/N = 3) for luteolin under optimized conditions. Besides, the influences of some coexistent phenolic compounds and common metal ions on luteolin detection were evaluated and no significant interference was observed. Finally, the sensor was successfully applied to the detection of luteolin in real Chrysanthemum tea samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flower-like A-ZnWO 4 /C composite material synthesized by ZIF-8 was reported. • Kaempferol electrochemical sensor based on A-ZnWO 4 /C was constructed for the first time. • A-ZnWO 4 /C/GCE showed ultra-sensitive detection towards kaempferol. • The method was successfully applied for analysis of kaempferol in natural samples. Kaempferol (KA), an important polyphenolic compound, is able to combat a variety of inflammatory diseases. Here, a ZnWO 4 / porous nanocarbon based electrochemical sensor has been constructed to detect KA for the first time. Innovatively, ZnWO 4 has been synthesized by pyrolysis using ZIF-8 as a zinc source, while porous nanocarbon was introduced. The nanocomposites have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy and demonstrated that Acidified ZnWO 4 /porous nanocarbon has been successfully prepared. Notably, the excellent catalytic properties of ZnWO 4 and the great enrichment ability and conductivity of porous nanocarbon greatly enhanced the detection performance of the sensor for KA with a linear range of 0.009–0.7 μM and a LOD of 2.03 nM. In addition, the sensor has obtained satisfactory results for the detection of KA in actual natural samples (broccoli and kaempferia powder). The reaction sites and redox mechanism of KA were shown by density functional theory. Finally, the sensor is highly sensitive and stable, making it a novel detection method with extremely high potential applications. [ABSTRACT FROM AUTHOR]

Temperature-controlled "On-Off" electrochemical behavior of hydroquinone at rGO@Au/PNVCL/m-BiVO 4 /GCE. [Display omitted] • A temperature-controlled electrochemical sensor for hydroquinone is constructed with good stability and reversibility. • The electrochemical sensor based on the composite exhibites electrochemical performance for HQ. • This sensor has wide linear detection range with low LOD of 0.6 μM. • The sensor has good stability and accurate characterization for detection in real samples. In this paper, a temperature-controlled "On-Off" electrochemical sensor for the detection of hydroquinone (HQ) is constructed by using a composite film of temperature-sensitive polymer poly (N-vinylcaprolactam) (PNVCL), the nanomaterial rGO@Au and the monoclinic bismuth metavanadate (m-BiVO 4). The sensor exhibits good temperature sensitivity and reversibility. When the temperature drops below the Lowest Critical Solution Temperature (LCST) of the PNVCL, the PNVCL will be in a "stretched" state, which hinders the electron exchange between hydroquinone and the surface of the electrode, presenting an "Off" state for the sensor. On the contrary, when the temperature exceeds the LCST, the PNVCL will be in a "contracted" state, which hydroquinone can perform an effective redox process and generate a response current, showing an "On" status. Due to the good electroconductivity and electrocatalytic ability of rGO@Au and m-BiVO 4 , the proposed sensor showed excellent detection performances. Hence, the sensor shows wide linear ranges (2.0 to 30.0 μM and 30.0 to 152.0 μM) and low limit of detection (0.6 μM). In addition, the "On-Off" electrochemical sensor may provide new ideas for the application of intelligent polymers. [ABSTRACT FROM AUTHOR]