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Herein, we fabricated a novel electrochemical sensor based on bismuth vanadate/graphite nanocomposites (BiVO 4 /Gr/GCE) for rapid and ultrasensitive detection of carbendazim. The fabricated BiVO 4 /Gr/GCE sensor exhibited better electrochemical performances toward carbendazim than the sensors that modified by BiVO 4 , Gr and bare-electrode, respectively. For the BiVO 4 /Gr/GCE nano-composite, the porous Gr possesses large specific area, almighty conductivity capability, high-efficiency charge transfer, while hollow BiVO 4 can promote the adsorption and electro-transfer efficiency of CBD on the BiVO 4 /Gr/GCE sensor. Additionally, Gr with remarkable conductivity could largely compensate the inferior-conductivity and prevent the aggregation dispersion of BiVO 4. The synergistic effect of BiVO 4 and Gr result in significant electro-activity good electrochemical sensing capability towards CBD. The fabricated sensor showed a wide linear response range in 4.0 × 10−8∼1.0 × 10−5, 1.0 × 10−5∼8.0 × 10−5 M with the correlation coefficient of R2 = 0.997 and R2 = 0.995, respectively. The limit of detection was 3.78 × 10−9 M (S/N = 3). Moreover, the proposed BiVO 4 /Gr/GCE sensor as well displays good operating stability, reproducibility, anti-disruptors, and repeatability for carbendazim detection. Furthermore, it was successfully used for carbendazim detection in pear and tomato juice with satisfactory recoveries of 90%∼108.3%, indicating that the sensor has a promising application for the detection of actual carbendazim. • An ultrasensitive electrochemical sensor via bismuth vanadate anchored graphite was first developed for the detection of carbendazim. • The proposed BiVO 4 /Gr sensor displays good operating stability, reproducibility, and repeatability for carbendazim detection. • The fabricated sensor showed a wider linear relationship and lower limit of detection. • The fabricated electrochemical sensor was successfully used for carbendazim detection in fruits and vegetables. [ABSTRACT FROM AUTHOR]

[Display omitted] • An electrochemical sensor with ultra-low detection limit was fabricated for the detection of carvacrol. • The developed Pb 0.95 Ti 0.05 O/NC sensor exhibited a wide detection range from 0.1 to 190 µM and a low detection limit of 0.054 μM. • The sensor demonstrated good stability, anti-interference, reproducibility and good repeatability. • The fabricated electrochemical sensor was successfully used for the detection of carvacrol in oregano essence, thyme essence and winter savory essence with satisfactory recoveries of 92.7% to 104.0%. Carvacrol has widely used in the field of medicine and sterilization. Thus, developing reliable, efficient, and rapid method for the carvacrol detection is meaningful. In this study, we fabricated a carvacrol sensor based on Pb 0.95 Ti 0.05 O decorated with nitrogen self-doped biochar (Pb 0.95 Ti 0.05 O/NC), which was synthesized by hydrothermal and carbonization of soybean root nodules, respectively. The prepared sensor exhibited better electrochemical performances than that of PbO, Pb 0.95 Ti 0.05 O, NC. The fabricated Pb 0.95 Ti 0.05 O/NC sensor exhibited a wide detection range from 0.1 to 190 µ M and a low detection limit of 0.054 µ M. The excellent electrochemical performances were attributed to the increased electron density and electron mobility after the introduction of Ti doping and nitrogen doped carbon. Mechanistic studies revealed that the electrochemical oxidation of carvacrol involves one electron and was limited by adsorption process. The sensor demonstrated good stability, anti-interference, reproducibility, and good repeatability. Moreover, the sensor displayed excellent recovery rates ranging from 92.7% to 102.9% when applied to the detection of carvacrol in real samples, making it a promising candidate for practical applications in the sensitive detection of carvacrol. [ABSTRACT FROM AUTHOR]

Schematic illustration of the formation of the MWCNTs−COOH/UiO-66-NH 2 /MWCNTs−COOH/GCE and the high selectivity electrochemical sensing for detecting Cd2+ and Pb2+ • An in situ growth method of UiO-66-NH 2 was developed. • Three-layer assembly of MWCNTs-COOH/UiO-66-NH 2 /MWCNTs-COOH film was fabricated. • Potentiostatic electrodeposition is a unique driving force for thin film manufacturing. • These structures of the sensor reveal high selectivity towards Pb2+ and Cd2+. • Effective rapid and simultaneous quantitative detective of Pb2+ and Cd2+ in water. In this work, an effective strategy for the fabrication of novel layer-by-layer multilayer films modified electrodes in electrochemical sensor applications. Glassy carbon electrode (GCE) surface has been modified with various multilayer films which were prepared by continuous repeated alternating electrodeposited of carboxylated multi-walled carbon nanotubes (MWCNTs−COOH) and Zr-metal-organic frameworks (UiO-66-NH 2). Newly constructed three-layer assembly of MWCNTs−COOH/UiO-66-NH 2 /MWCNTs−COOH/GCE as voltammetric sensor was adapted to simultaneous detection Cd2+ and Pb2+ by square-wave anodic stripping voltammetry (SWASV). Meanwhile, the formation of MWCNTs−COOH/UiO-66-NH 2 /MWCNTs−COOH/GCE is supported by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), X-ray photoelectron spectra (XPS), X-ray diffraction patterns (XRD), and Fourier transform infrared spectra (FT-IR), which have been researched to estimate the effect of their electrochemical detection. Here, combined the abundant adsorption sites of UiO-66-NH 2 with excellent conductivity ability of MWCNTs−COOH, and the dominant characteristics of the chelation mechanisms between amine groups and heavy metal cations, which strengthened its electrocatalytic activity. Results show that three-layer film modified GCE (MWCNTs−COOH/UiO-66-NH 2 /MWCNTs−COOH/GCE) can acquire the optimal simultaneous detection performances as the higher sensitivities to Cd2+ (0.2528 μA ppb−1) and Pb2+ (0.3012 μA ppb−1), the lower level detection limits to Cd2+ (0.090 ppb) and Pb2+ (0.071 ppb), as well as the superior linear relativity, respectively. Finally, excellent stability, repeatability and reproducibility of three-layer film modified GCE allow this sensing platform to work in practical application. The strategy that used layer by layer electrodeposition to assemble multilayer films will provide great potential for advanced applications in environment, biomedicine, human health and energy field. [ABSTRACT FROM AUTHOR]