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P -nitrophenol (PNP) has been widely applied to industry processing for many purposes, but the persistence and toxicity of residuum may pose risks to human health. To analyze PNP in industrial and agricultural wastewater, a versatile fluorescent probe sensing platform was proposed. In this work, we devised a fluorescence approach that utilized nitrogen, silicon co-doped carbon dots (N,Si-CDs) to monitor PNP originating from the inner filter effect (IFE). The N,Si-CDs were generated in a one-step hydrothermal synthesis, and which possessed outstanding fluorescence signal and water-dispersity. Emission at 441 nm was monitored with excitation at 360 nm using a common spectrofluorometer. The method achieved an exceptionally low limit of detection (LOD) of 0.011 μM. Furthermore, this method not only eliminates the interference from metal ions and acid ions, but also provides a potential application prospect for N,Si-CDs in the field of water monitoring. Analysis of tap and lake water led to 93.30–106.30% recoveries and <1% relative standard deviation at 2.5–25 μM PNP concentrations. Unlabelled Image • A novel fluorescence nanoprobe based on N,Si-CDs was designed for PNP detection. • The N,Si-CDs possessed outstanding fluorescence signal and water-dispersity. • This fluorometric assay has lower detection limit than other detection methods. • This fluorescence nanoprobe had been used to detect PNP in actual water samples with great recoveries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel bimetallic organic framework based fluorescent aptamer probe was designed. • Aptamer was combined with Cu/UiO-66 by electrostatic force and van der Waals force. • Aptamer's fluorescence was quenched by the photoinduced electron transfer effect. • The probe realized sensitive detection of zearalenone in cereal and their products. • A detection limit of 0.048 ng/mL was achieved with a linear range of 0.5–60 ng/mL. In this work, a bimetallic organic framework (Cu/UiO-66) based "turn on" fluorescent aptamer probe was designed for the high-efficiency detection of zearalenone (ZEN). In the probe, the 6-carboxyfluorescein-labeled aptamer (FAM-Apt) was used as the recognition element, and the electrostatic interaction, coordination effect, and photoinduced electron transfer effect between FAM-Apt and Cu/UiO-66 caused fluorescence quenching. When ZEN existed, FAM-Apt recognized ZEN specifically, causing FAM-Apt to separate from the surface of Cu/UiO-66 and recovery of fluorescence. Under the optimal conditions, the probe had a linear detection range of 0.5 ng/mL–60 ng/mL, and the detection limit was 0.048 ng/mL. The application potential of the probe was verified by real detection of various cereals and their products, with a standard recovery from 83.67 %–106.8 %. The development of this efficient, rapid, and sensitive ZEN detection method provides a new platform for the quality control of cereals and their products. [ABSTRACT FROM AUTHOR]

Mercury (II) ions (Hg2+), as one of the most toxic heavy metals, can cause irreversible damage to human health even at very low concentration due to its high toxicity and bioaccumulation. Herein, a facile ratiometric fluorescence nanomixture based on carbon dots‑gold nanoclusters (CDs-Au NCs) was constructed for quantitative detection of Hg2+. Lysine functionalized carbon dots (CDs) were prepared by one-pot hydrothermal method, while gold nanoclusters (Au NCs) were synthesized via using chicken egg white (CEW) as reducer and stabilizer. The novel nanomixture exhibited two strong emission peaks at 450 nm and 665 nm under 390 nm excitation, and showed pink fluorescence under UV light. Interestingly, the fluorescence of the CDs-Au NCs nanomixture was selectively response to Hg2+. The fluorescence of Au NCs at 665 nm was decreased when Hg2+ was presented in the solution, while the fluorescence of CDs at 450 nm stayed constant. The fluorescence color changed from pink to blue obviously with increasing the concentration of Hg2+, which indicated that CDs-Au NCs could be used for visual detection Hg2+ by the naked eye. Under optimal conditions, this ratiometric fluorescent sensor could detect Hg2+ accurately and possess a great sensitivity with a detection limit of 63 nM. In addition, this method was applied to detect Hg2+ in real water samples with great recoveries, suggesting its potential in practical application with simplicity, environmentally friendly and low cost. Unlabelled Image • A novel ratiometric fluorescence sensor based on CDs-Au NCs was designed for Hg2+ detection. • The sensor was constructed by simply mixing CDs and Au NCs together. • As precursors, lysine and chicken egg white were easily available and environmentally friendly. • The fluorescence color varied from pink to blue which could be clearly recognize. • This sensor had been used to detect Hg2+ in real water samples with great recoveries. [ABSTRACT FROM AUTHOR]

The valorization, resource generation and the functional characteristic exploration of domestic waste still face enormous challenges. Kiwi peels, a common kind of fruit waste, contain a large amount of phenolic substances, including polyphenols, flavonoids, etc., which can be explored and reused in food and biomedical fields. By ultrasonic assisted extraction technology, we obtained conversional fluorescence kiwi peel phenolic extracts (PE) which possessed gradient magenta fluorescence relying on the content of ethanol in the solution, as well as strong antioxidant activity. Besides, metal ions sensing assay revealed that PE can specifically sense Hg2+ and Cu2+ (LOD: 1.16 and 0.17 μM, respectively) accompanied with a fluorescence conversion from magenta fluorescence to blue. Moreover, employing the prepared PE as fluorescent probes, imaging of HeLa cells can be easily achieved with satisfactory resolution. Additionally, PE was incorporated into the gelatin matrix, successfully fabricating a green, edible degradable film with excellent antioxidant activity. Unlabelled Image • Ultrasound treatment accelerated the escape of kiwi peel phenolic extracts. • Phenolic extracts exhibited a gradient magenta fluorescence relying on the solvent effects. • Phenolic extracts sense Hg2+ and Cu2+ with a fluorescence conversion from magenta to blue. • Phenolic extracts were successfully applied to fluorescent imaging of HeLa cells. • Phenolic extracts improved the antioxidant capacity of gelatin-based films. [ABSTRACT FROM AUTHOR]