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The abuse of tetracycline (TC) has led to serious threats to human health and the environment. Therefore, the rapid and sensitive detection of tetracycline is of particular importance. Herein, we successfully synthesised a bimetallic nanozyme D-Fe/Co-MOF with oxidase activity and established a colourimetric sensor. The complex of Fe2+ in D-Fe/Co-MOF and TC can release hydroxyl radicals (˙OH) and promote the oxidation of TMB. As a result, the colour of the detection system significantly changes, enabling the sensitive colourimetric detection of TC. Compared with the existing Fe/Co-MOF sensor, D-Fe/Co-MOF can effectively reduce the detection error caused by hydrogen peroxide decomposition, improving the accuracy of TC detection. Under the optimal conditions, the absorbance at 652 nm showed a good linear relationship with TC concentration in the range of 0.35–220 μg mL−1. The detection limit was as low as 0.0719 μg mL−1, considerably lower than the national safety standard. The proposed colourimetric sensor was also successfully used for the detection of TC in actual milk samples, and the results were in good agreement with those obtained via liquid chromatography. The proposed strategy for the detection of TC in food is expected to contribute to ensuring food safety and human health. [ABSTRACT FROM AUTHOR]

Based on the brief introduction of the dangers of antibiotic residues and the current status of antibiotic detection technology, the fluorescence sensing methods based on carbon quantum dots, semiconductor quantum dots, metal-organic framework materials and upconversion nanomaterials for antibiotic detection application were reviewed. It pointed out that compared with traditional detection methods, fluorescence sensor detection method had the advantages of speediness, high sensitivity and visualization. However, due to the food matrix effect, complex sample pretreatment steps were often required to purify and enrich the target substance. Therefore, appropriate pre-treatment technologies or matrix purification methods, new novel fluorescent nanomaterials, portable sensing detection equipment suitable for on-site detection, and the specificity of detection by combining aptamer, antibody and molecular imprinting techniques were the technological trend. It was expected that this review was able to provide a reference and theoretical basis for the practical applications of fluorescence sensing technology in antibiotic detection in the future. [ABSTRACT FROM AUTHOR]

Designing low-cost and effective electrode materials is a pressing but challenging task for fabricating electrochemical sensors. Herein, a pH-regulated electrodeposition method was proposed for the facile synthesis of CuOx/electrochemically reduced graphene oxide (ERGO) nanohybrids. Besides, the relationships between the structures of CuOx/ERGO nanohybrids and the corresponding properties were investigated. It was found that the CuOx/ERGO nanohybrid-based electrochemical sensor displayed different catalytic abilities towards nitrite sensing, following the order honeycomb-like structure ＞ peony-like structure ＞ rose flower-like structure ＞ crape myrtle flower-like structure. Honeycomb-like CuOx/ERGO nanohybrids were used to fabricate an electrochemical sensor. This sensor not only achieved accurate and sensitive detection of nitrite in a wide linear range of 0.1–100 μM with a low detection limit of 0.072 μM but could also be applied in the detection of nitrite in drinking water and meat samples with acceptable recovery and stability. The established method may have potential application value for on-site safety regulation on nitrite in the environment and food. And, research on the structure–property relationship of the electrode modified material has certain theoretical value for the development of new methods for electrocatalytic nitrite oxidation. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a one-pot solvothermal synthetic method for fabricating MFe2O4 (M = Mn, Co)–MoS2–carbon dot (CD) nanohybrid composites (MnFMC, CoFMC) with excellent Pb(ii) removal ability. Detailed characterization through SEM, XRD, UV-vis spectra, fluorescence spectra and VSM confirmed the formation of the nanohybrid composites. The adsorption behavior of the as-prepared nanohybrids was systematically studied using kinetic and equilibrium experiments, and the adsorption mechanism was further revealed using XPS and FTIR. Taking advantage of the cation substitution of abundant functional groups on the surface of CDs and MFe2O4 nanoparticles, as well as the large surface of available MoS2 for enhancing the sequestration of target metal-pollutants, the as-prepared composites exhibit high adsorption performances (588.24 mg g−1 for MnFMC and 660.67 mg g−1 for CoFMC) and show preferential Pb(ii) sorption behavior with a high level concentration of competing cations (Ca(ii)/Mg(ii)). Moreover, these nanohybrid adsorbents exhibit excellent reusability, lower the effluent Pb(ii) contents down to the ppb level, which satisfies the drinking water standard recommended by the World Health Organization, and are promising candidates for water purification. [ABSTRACT FROM AUTHOR]

Developing low-cost, efficient, and bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an appealing yet challenging task. Herein, for the first time, a NiS microsphere film was grown in situ on Ni foam (NiS/Ni foam) via a sulfurization reaction as an efficient bifunctional electrocatalyst for overall water splitting with superior activity and good durability. This NiS/Ni foam electrode delivers 20 mA cm−2 at an overpotential of 158 mV for the HER and 50 mA cm−2 at an overpotential of 335 mV for the OER in 1.0 M KOH. This bifunctional electrode also enables a high-efficiency alkaline water electrolyzer with 10 mA cm−2 at a cell voltage of only 1.64 V, which could be promising in water splitting devices for large-scale hydrogen production. [ABSTRACT FROM AUTHOR]

In this work, the double-edged effect of curcumin (Cur) on Maillard reaction (MR) in model milk pasteurization process was demonstrated for the first time, where Cur inhibits MR at low concentrations (<5 μg/mL), while promotes it at high concentrations (>5 μg/mL). A nanocapsule strategy was introduced to resolve the disadvantages of Cur on MR at high temperature. In vitro experiments confirmed that curcumin @ polyvinylpyrrolidone nanocapsules (Cur@PVP NCs) synthesized by a one-pot method can control the continuous and slow release of Cur and exert inhibitory effect on MR by competing with lactose for casein, trapping the reactive dicarbonyl compounds and scavenging ROS, which might provide a new strategy for the application of functional food ingredients in the control of MR during food heat processing, including milk pasteurization. [ABSTRACT FROM AUTHOR]

As one of most common synthetic phenolic antioxidants, tertiary butylhydroquinone (TBHQ) has received increasing attention due to the potential risk for liver damage and carcinogenesis. Herein, a simple and rapid fluorescent switchable methodology was developed for highly selective and sensitive determination of TBHQ by utilizing the competitive interaction between the photoinduced electron transfer (PET) effect of carbon dots (CDs)/Fe(III) ions and the complexation reaction of TBHQ/Fe(III) ions. This novel fluorescent switchable sensing platform allows determining TBHQ in a wider range from 0.5 to 80 μg mL(-1) with a low detection limit of 0.01 μg mL(-1). Furthermore, high specificity and good accuracy with recoveries ranging from 94.29 to 105.82% in spiked edible oil samples are obtained with the present method, confirming its applicability for the trace detection of TBHQ in a complex food matrix. Thus, the present method provides a novel and effective fluorescent approach for rapid and specific screening of TBHQ in common products, which is beneficial for monitoring and reducing the risk of TBHQ overuse during food storage.