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The first fluorescent sensor based on the indicator displacement assay (IDA) for on-site determination of etomidate. [ABSTRACT FROM AUTHOR]

Tetracyclines (TCs) are a group of broad-spectrum antibiotics against multiplying microorganisms yet with several adverse effects on humans. Since all types of TCs have the similar chemical skeleton and mechanism of action, quantification of total amount of TCs in the environment was of particular importance. To date, dozens of fluorescent probes have been reported for TCs detection, but only very few of them enabled detection of total TCs. In this study, we report a novel supramolecular sensor constructed by human serum albumin as the recognition moiety and a flavonol fluorophore as the indicator. Under the 370 nm UV excitation, this sensor exhibits the rapid response (5 s), acceptable sensitivity (limit of detection ∼ 0.58 μM), long dynamic detection range (0–20 μM), prominent specificity, and excellent anti-interference properties for analysis of total TCs. The mechanism was carefully validated using 1H NMR, fluorescence titration experiments, molecular docking, and mass spectrometry. We expect this work can inspire more sensor design for TCs quantification. [Display omitted] • A novel fluorescent sensor enables detection of total amount of tetracyclines. • This method can detect tetracycline with rapid response and high selectivity. • The limit of detection for tetracyclines can reach 0.58 μM. • Accurate detection of total tetracycline in real samples is achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first pH fluorescent sensor with two pKa values. • This sensor enables monitoring of pH with the dual-color response. • The portable paper strips can be facilely fabricated based on the sensor. • The paper strips can be successfully employed for the real food analysis. Tracking pH fluctuations in food samples is important for ensuring food freshness. Fluorescent probes have been widely applied as promising tools for the on-site detection of pH changes; however, most of them can be applied only at either lower or higher pH ranges because their response structures commonly have a single acid dissociation constant (pKa). To address this problem, we designed a fluorescent sensor, called HMB, containing a methylpiperazine group with two pKa values, which exhibited a unique dual-color response to pH changes over a wide pH range. Furthermore, the HMB-based test strips are easily prepared and used as portable labels for the visual monitoring of food spoilage that results in microbial and anaerobic glycolytic pathways in real food (such as cheese and shrimp). To the best of our knowledge, this is the first fluorescent pH sensor with two pKa values, and we expect that this work will inspire more sensor designs for food quality control. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first fluorescent sensor for ratiometric detection of permethrin is reported. • This sensor exhibited rapid response, high sensitivity and high selectivity. • The limit of detection for permethrin was 0.08 μM (29 ppb). • This sensor successfully achieved monitoring of permethrin in real food samples. Permethrin (PMT) is a broad-spectrum synthetic pyrethroid insecticide widely used for treatment of insects in agriculture. Yet the massive use of PMT comes at the cost of its residue ubiquitous in the environment thereby causing a significant risk to human health. Therefore, development of an analytical method for accurate detection of PMT at the point-of-care is of great importance. In this study, we report a novel single-fluorophore-based supramolecular sensor with dual emissions as ratiometric output signals, successfully realizing the fast detection of PMT with the self-calibrating feature. This sensor exhibited several advantages for PMT detection, such as fast response, high sensitivity, high specificity, and excellent anti-interference property. Notably, this sensor could be used for on-site monitoring of PMT residues on the food surface without the help of complicated testing facilities. To our best knowledge, this is the first promising fluorescent method for the fast and ratiometric determination of PMT. [ABSTRACT FROM AUTHOR]