Rapid and Visual Detection of Benzoyl Peroxide in Food by a Colorimetric and Ratiometric Fluorescent Probe

Construction of a double-increasing emission fluorescent probe and its application in food detection of benzoyl peroxide and biosystem imaging

In this work, based on the Förster resonance energy transfer (FRET) mechanism strategy, a new dual-increasing emission proportional near-infrared (NIR) fluorescent probe Lay-1 was designed for fast benzoyl peroxide (BPO) detection in real food samples and biosystems. Specifically, it employed a naphthylimide derivative and a NIR fluorophore dicyanoisophorone derivative as the energy transfer donor and acceptor, respectively, and a phenylboronic acid (Ph-B(OH)2) as the responding group of BPO. In addition, the results exhibited that the fluorescence color of Lay-1 was changed from red to orange in the absence and the presence of BPO with a fast response time (∼120 s), high sensitivity, and an excellent limit of detection as low as 60.8 nM. Impressively, Lay-1 has been successfully used for BPO detection in real food samples and biosystems with satisfactory results. Therefore, Lay-1 can be a robust molecular tool to further investigate the physiological and pathological function of BPO.

A high-fidelity dual-channel fluorescence probe for benzoyl peroxide detection and toxicity early warning in food, zebrafish, and mice

Benzoyl peroxide (BPO), as a widely used organic peroxide, has attracted widespread attention from all sectors of society for its environmental hazards and potential risks to human health. Herein, we employed a Förster resonance energy transfer (FRET) strategy to construct a novel ratiometric fluorescent probe CY-DCI for BPO detection in food, zebrafish, and mice. Specifically, a hemicyanine fluorophore and a dicyanoisophorone fluorophore were connected with a piperazine group as donor and acceptor, respectively, and an olefinic unsaturated bond as the reaction site. CY-DCI has favorable selectivity and an excellent detection limit as low as 58.1 nM, and the recovery rates for real-sample detection ranged from 95.8 % to 104 %, with relative standard deviations (RSD) less than 2.58 %. To further improve its practicality, silica gel plates and test strips containing CY-DCI (0-50 μM) were developed for naked-eye detection of BPO with satisfactory results. Additionally, this novel probe was then applied for ratiometric imaging of living zebrafish and mice and showed high ratiometric imaging resolution in the green and red channels, thus demonstrating its practical application for BPO detection and toxicity early warning in food and biosystems.

AIE fluorescent nanozyme-based dual-mode biosensor for analysis of the bioactive component hypoxanthine in meat products

The development of facile, low-cost reliable, and precise onsite assays for the bioactive component hypoxanthine (Hx) in meat products is significant for safeguarding food safety and public health. Herein, we proposed a smartphone-assissted aggregation-induced emission (AIE) fluorogen tetraphenylethene (TPE)-incorporated amorphous Fe-doped phosphotungstates (Fe-Phos@TPE) nanozyme-based ratiometric fluorescence-colorimetric dual-mode biosensor for achieving the onsite visual detection of Hx. When the Hx existed, xanthine oxidase (XOD) catalyzed Hx into H2O2 to be further catalyzed into •OH by the prominent peroxidase activity of Fe-Phos@TPE at pH = 6.5, resulting in the oxidization of nonfluorescent o-phenylenediamine (OPD, naked-eye colorless) to be yellow fluorescent emissive 2,3-diaminophenazine (DAP, naked-eye dark yellow) at 550 nm as well as the intrinsic blue fluorescence of Fe-Phos@TPE at 440 nm to be decreased via inner-filter effect (IFE) action, thereby realizing a multi-enzyme cascade catalytic reaction at near-neutral pH to overcome the traditional acidity dependence-induced time-consuming and low sensitivity troublesome.

A dual-reaction sites fluorescent probe for accurate detection of benzoyl peroxide in food

Benzoyl peroxide (BPO) is widely used as a whitening agent in flour, but excessive intake of BPO will severely endanger human health. To quickly and accurately detect BPO on-site, we have rationally designed a novel fluorescent probe PTPY-BE with dual-reaction sites. PTPY-BE underwent a specific cascade reaction with BPO to achieve high-contrast fluorescence turn-on response along with significant achromic reaction. The probe has high sensitivity, excellent selectivity, strong anti-interference ability and low detection limit (LOD = 0.83 mg·kg-1) for BPO. Furthermore, a portable detection platform was fabricated, which offers the portability and color visualization of traditional test strips and the color recognition of a smart device, enabling on-site visualization and quantitative detection of BPO. This platform has been successfully used to determine BPO in real food samples with good recoveries (93.59% - 107.13%). Therefore, this platform possessed great prospect and potential application for the determination of BPO in food.

A portable smartphone platform utilizing dual-sensing signals for visual determination of semicarbazide in food samples

Semicarbazide (SEM) is a metabolite of antibiotic nitrofurazone and a food contaminant in food production, showing potential carcinogenic, mutagenic, teratogenic, and toxic effects on human health. It is urgent to develop a highly efficient and sensitive assay for visual detection of SEM. In this paper, a pyrrolopyrrole cyanine fluorescent probe (PPCy-1) was reported for visualization and quantitative analysis of SEM through a chromophore reaction sensing mechanism for the first time. The probe towards SEM exhibited a fast response (10 min), a low detection limit (0.18 μM), high selectivity, and distinct dual ratiometric fluorescence turn-on and colorimetric modes. Its practicability was further verified by detecting SEM in meat, water, and honey samples with satisfactory recovery values. More importantly, a smartphone-assisted portable testing platform was constructed based on a PPCy-1-immobilized test paper or a polyamide thin film with a color scanning APP for real-time and on-site detection of SEM. This work provides low-cost, convenient, and rapid assays for visual SEM detection, which have potential applications in food safety monitoring.

Biomass-based indole derived fluorescence sensor composited with cellulose paper: Detection of picric acid in food and environment samples

Picric acid (PA) is highly water-soluble, the fact makes it stand out as the most hazardous environment pollutant. Therefore, accurate determination of PA is of great significance for human health and environmental protection. Herein, a novel indole-based fluorescent sensor (H1) with good water solubility and fluorescence stability was reported. H1 exhibited 'turn-off' fluorescence response for PA with fast reaction rate (<30 s), unique specificity and excellent selectivity and high sensitivity (limit of detection = 34 nM). Further, H1 was successfully applied to detect PA in real samples (tap water, Yangtze River, Xuanwu Lake, soil, food, fish and shrimp) with satisfactory recoveries at three spiking levels ranging from 98.0 to 112.0 %. In addition, H1 displayed high biocompatibility in mung beans and fresh blood. Moreover, aiming to attain portable analysis, H1 was composited with biomass cellulose paper (H1-FP) and integrated with smartphone for construction as a solid-state fluorescence platform to achieve fast and visual detection of PA in suit with significant stability, high sensitively and selectivity. The establishment of this sensing approach is expected to offer new insight into rapid, selective, and sensitive detection of major pollutants for food and environmental safety.

An intelligent smartphone-test strip detection platform for rapid and on-site sensing of benzoyl peroxide in flour samples

Benzoyl peroxide (BPO) is a commonly used flour whitener, but its excessive usage can have adverse effects on human health, such as nutrient loss, vitamin deficiencies and certain diseases. In this study, a europium metal organic framework (Eu-MOF) fluorescence probe was prepared, which exhibited a strong fluorescence emission at 614 nm upon excitation at 320 nm, with a high quantum yield of 8.11%. The red fluorescence of the probe could be effectively quenched by BPO through the inner filter effect (IFE) and photoinduced electron transfer (PET) mechanism. The detection process offered several advantages, including a wide linear range of 0-0.95 mM, a low detection limit of 66 nM and a fast fluorescence response of 2 min. Furthermore, an intelligent detection platform was designed to enhance the practical application of the detection method. This platform combined the portability and visuality of a traditional test strip with the color recognition capability of a smartphone, allowing for the visualization and quantitative detection of BPO in a convenient and user-friendly manner. The detection platform was successfully applied to the analysis of BPO in real flour samples with satisfactory recoveries (99.79%-103.94%), suggesting a promising strategy for the rapid and on-site detection of BPO in food samples.

A highly selective and sensitive europium-organic framework sensor for the fluorescence detection of fipronil in tea

A europium-based metal organic framework (Eu-TFPA-MOF) was used for the fluorescence detection of fipronil in green tea and oolong tea for the first time. The red fluorescence of Eu-TFPA-MOF could be quenched significantly by low concentration (0.24 mM) of fipronil, and the "turn off" process exhibited quick response time (2 min), high sensitivity and selectivity, low detection limits (4.4 nM) and wide linear range (0-0.15 mM). The mechanism of fluorescence quenching was mainly attributed to static quenching process and the competitive absorption of excitation energy. Besides, the spiked and recovery test indicated that Eu-TFPA-MOF could be used in the fluorescence detection of fipronil in real green tea and oolong tea sample and the process had the advantages of simple pretreatment and satisfactory recoveries (98.33-106.17 %). More importantly, a simple, portable and low-cost smartphone-assisted test strip were designed for the visual detection of fipronil in real tea samples. The detection platform will be beneficial for tea quality safety and human heath, and is expected to be applied in other agricultural product safety field.

A portable paper-based testing device for fast and on-site determination of nitroxynil in food

Nitroxynil (NTX) is a common anthelmintic veterinary drug for the management of fascioliasis in food-producing sheep and cattle. Since excessive NTX residue in food can lead to several adverse side effects, such as allergic skin reaction and respiratory irritation, it is of great importance to develop an efficient analytical method for NTX determination. Herein, we report a simple fluorescent detection method based on a novel supramolecular probe capable of detecting NTX with a fast response (5 s), high sensitivity (107 nM), high selectivity, and acceptable anti-interference property. Moreover, the portable paper-based test strips were facilely prepared and successfully realized on-site determination of NTX in real edible animal products simply with the aid of a smartphone. To the best of our knowledge, this is the very first report on the portable detection of NTX. This study also provides a promising strategy for the fast and portable detection of analyte based on the host-guest system, which will lead to improved fluorescent probe design for food analysis.

Perylene-Based Smart Fluoroprobe with Dual Function: Ratiometric Response toward Hazardous Organic Peroxides and Pure White Light Generation via Self-Assembly

In this report, we have designed and synthesized a perylene-based smart fluoroprobe (PBE) in which the perylene core has been functionalized with the boronate group at the peri-position. PBE shows a very fast and ratiometric response toward harmful organic peroxides (OPs) generated in old ethereal solvents via auto-oxidation. The response toward OPs takes place with a visible color change from green to yellow, which could be easily observed with the naked eye. The reaction between PBE and OPs involves the cleavage of the boronate group and its consequent conversion into the -OH group. The response of PBE toward OPs was monitored using UV-vis absorption, fluorescence emission, IR spectroscopy, and mass spectrometry. Additionally, we have also explored the self-assembly of PBE in an organic-aqueous solvent mixture, which shows pure white light emission (WLE) with the CIE coordinates (0.33, 0.33) in a 50% dimethyl sulfoxide-water mixture. This work clearly reveals that PBE fluoroprobe can be employed for sensitive detection of hazardous OPs present in old ethereal solvents. Moreover, the ability of PBE to generate the perfect pure WLE makes it a potential candidate for application in organic light-emitting devices.

A FRET-based ratiometric fluorescent probe for Hg2+ detection in aqueous solution and bioimaging in multiple samples

Mercury ion, as a metal cation with great toxic effect, is widely present in various production and living environments. It seriously threatens human health and environmental safety. It is of great significance to develop convenient and effective methods for mercury ion detection. Here, we designed and synthesized a new ratiometric fluorescent probe (namely APS-NA) for the detection of mercury ions in the environment and multiple biological samples. The probe is constructed by covalently connecting two fluorophores with lipolic acid to achieve fluorescence resonance energy transfer (FRET). In the molecular structure of APS-NA, acridone is used as an energy donor, 1,8-naphthalimide is used as an energy acceptor, and a dithioacetal group is used as the reaction site for Hg²⁺. The intact APS-NA mainly shows the green fluorescence from the acceptor moiety 1,8-naphthalimide; the presence of Hg²⁺ ions would break the dithioacetal linkage between acridone and 1,8-naphthalimide; the defunctionalization of FRET would lead to bright blue fluorescence emission of acridone; thus ratiometric fluorescent detection of Hg²⁺ can be achieved by this recognition process. The probe not only has a large Stokes shift (Δλ = 110 nm), but also has high selectivity, high sensitivity (low detection limit 30 nM) and naked eye visualization. In addition, we have successfully used this probe for the detection Hg²⁺ of actual samples and imaging of a variety of organisms. These results indicate that the probe has broad application prospects.

A hemicyanine-based near-infrared fluorescent probe for vapor-phase hydrazine detection and bioimaging in a complete aqueous media

A novel near-infrared fluorescent probe CyOE based on hemicyanine dye containing acetyl as a recognition site is reported. The probe CyOE shows high selectivity and sensitivity (LOD = 82 nM, 2.58 ppb), as well as good water solubility and quantitative detectability of hydrazine in the concentration range of 0-75 μM (R² = 0.993). Moreover, CyOE has a significant increase in fluorescence at 735 nm with the addition of N₂H₄, which provides a rapid, colorimetric and gas-phase detection method for N₂H₄ in both aqueous solution and real water samples. In addition, CyOE is successfully utilized to visualize hydrazine in cells with low cytotoxicity and high cell permeability.

Biomass-based indole derived composited with cotton cellulose fiber integrated as sensitive fluorescence platform for NH3 detection and monitoring of seafood spoilage

Herein, an indole-derived water-soluble fluorescence nanomaterial and biomass-based cellulose filter paper integrated as solid-state fluorescence platform (H2-FP) for seafood spoilage detection was prepared. H2 exhibits high fluorescence stability and good biocompatibility with green beans, onion tissues, blood and zebrafish, which proving that H2 has a wide range of application scenarios. Further, H2-FP with effective, solid-state fluorescence, portable, and reusable characteristics is nanoengineered for NH₃ quantitative and qualitative detection (DOL = 2.6 ppm). Then, H2-FP has been successfully used to monitor NH₃ release in the seafood spoilage process at various storage time (4 °C and 25 °C). More importantly, fluorescence color of H2-FP is integrated smartphone are converted to digital values through RGB channels and successfully used to visualize semi-quantitative recognition of NH₃. This sensing fluorescence platform integrated with smartphone furnishes an effective fabrication strategy and broad prospects for explore various biomass-based materials for sensing NH₃ change in biological and environmental samples.

A luminescent Eu3+-functionalized MOF for sensitive and rapid detection of tetracycline antibiotics in swine wastewater and pig kidney

Tetracyclines (TCs), a type of antibiotics, are widely used in human therapy and animal husbandry. Public concerns about tetracyclines residues have been raised due to their negative impact on the environment and food, causing bacterias drug resistance and human health concerns. In this work, a luminescent europium MOF (EuUCBA) is constructed via post-synthetic attachment of Eu³⁺ into a UiO-66 type MOF. The luminescent of EuUCBA exhibits high stability in aqueous media in the pH range of 4-11. Among 36 common veterinary drugs, the synthesized probe is highly selective and sensitive to six tetracyclines with low detection limits of 0.118 μM, 0.228 μM, 0.102 μM, 0.138 μM, 0.206 μM, and 0.078 μM for oxytetracycline (OTC), chlortetracycline (CTC), methylenetetracycline (MTC), minocycline (MOC), tetracycline (TC), and doxycycline (DOXY), respectively. Furthermore, the probe shows good anti-interference ability and fast response. Finally, EuUCBA was successfully to detect DOXY in swine wastewater and pig kidney with good recoveries. This work provides an excellent fluorescent sensor for highly selective and rapid detection of TCs residues in wastewater and complex biological samples.

Fast visual monitoring of the freshness of beef using a smart fluorescent sensor

Spoiled meat contains many pathogenic bacteria; hence, the intake of spoiled food can lead to various illnesses. To screen the freshness of food, in this study, we devised a ratiometric fluorescence sensor dicyanovinyl coumarin (CMDC) for the determination of cadaverine, an important biomarker for the spoilage of meat. CMDC underwent aza-Michael addition with cadaverine, exhibiting high sensitivity, fast response (50 s), and distinct fluorescence color transition. Test strips fabricated using CMDC showed a noticeable color change from red to green when exposed to cadaverine vapor. The test strips were successfully used to visually monitor the spoilage of beef based on the fluorescence color change. Furthermore, the as-developed test strip coupled with a smartphone provides a simple tool for consumers and suppliers to obtain information about meat quality.

Application of near-infrared spectroscopy for the nondestructive analysis of wheat flour: A review

The quality and safety of wheat flour are of public concern since they are related to the quality of flour products and human health. Therefore, efficient and convenient analytical techniques are needed for the quality and safety controls of wheat flour. Near-infrared (NIR) spectroscopy has become an ideal technique for assessing the quality and safety of wheat flour, as it is a rapid, efficient and nondestructive method. The application of NIR spectroscopy in the quality and safety analysis of wheat flour is addressed in this review. First, we briefly summarize the basic knowledge of NIR spectroscopy and chemometrics. Then, recent advances in the application of NIR spectroscopy for chemical composition, technological parameters, and safety analysis are presented. Finally, the potential of NIR spectroscopy is discussed. Combined with chemometric methods, NIR spectroscopy has been used to detect chemical composition, technological parameters, deoxynivalenol, adulterants and additives of wheat flour. Furthermore, NIR spectroscopy has shown great potential for the rapid and online analysis of the quality and safety of wheat flour. It is anticipated that the current review will serve as a reference for the future analysis of wheat flour by NIR spectroscopy to ensure the quality and safety of flour products.

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NIR spectroscopy is an ideal technique for analysis of wheat flour due to its rapid and nondestructive nature.

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Use of NIR spectroscopy for chemical composition, technological parameters, and safety analysis.

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Online and handheld NIR spectrometers for wheat flour detection are the future trends.

Recyclable europium functionalized metal-organic fluorescent probe for detection of tryptophan in biological fluids and food products

An europium functionalized metal-organic fluorescent probe, Eu³⁺@UiO-66-FDC was constructed by post-synthetic modification through coordination interactions. Eu³⁺@UiO-66-FDC displayed high selectivity and sensitivity toward Tryptophan (Trp) among all the 20 natural amino acids and other general compounds in food and biological samples, with a wide linear concentration range (0-1000 μM), low detection limit (0.29 μM), and a rapid response (<1 min). Besides, this probe was utilized to detect Trp in rabbit blood serum and milk samples with good recoveries, which were verified by high-performance liquid chromatography (HPLC). Notably, this fluorescent probe proved to be a recyclable material. Hence, this work provides a reliable and recyclable fluorescent probe applicable toward the detection of Trp in biological fluids and/or food products.

Resorufin-based responsive probes for fluorescence and colorimetric analysis

The fluorescence imaging technique has attracted increasing attention in the detection of various biological molecules in situ and in real-time owing to its inherent advantages including high selectivity and sensitivity, outstanding spatiotemporal resolution and fast feedback. In the past few decades, a number of fluorescent probes have been developed for bioassays and imaging by exploiting different fluorophores. Among various fluorophores, resorufin exhibits a high fluorescence quantum yield, long excitation/emission wavelength and pronounced ability in both fluorescence and colorimetric analysis. This fluorophore has been widely utilized in the design of responsive probes specific for various bioactive species. In this review, we summarize the advances in the development of resorufin-based fluorescent probes for detecting various analytes, such as cations, anions, reactive (redox-active) sulfur species, small molecules and biological macromolecules. The chemical structures of probes, response mechanisms, detection limits and practical applications are investigated, which is followed by the discussion of recent challenges and future research perspectives. This review article is expected to promote the further development of resorufin-based responsive fluorescent probes and their biological applications.

The ratiometric fluorescent probes for monitoring the reactive inorganic sulfur species (RISS) signal in the living cell

RSSs (reactive sulfur species) and their metabolites, such as H₂S, S_n^2-, SO₃^2-/HSO₃^-, S₂O₄^2- and S₂O₅^2- (Reactive Inorganic Sulfur Species, RISSs), play a crucial role in the cushion against oxidative stress and the other physiological events. The molecular mechanisms how they affect cellular signaling and other physiological events remain largely unknown. To address their physiological functions, the techniques that can track their levels should be invaluable. Herein, six coumarin hemicyanine scaffolds (CH-RISSs) were synthesized and their fast and strong responses upon H₂S, S_n^2-, SO₃^2-, HSO₃^-, S₂O₄^2- and S₂O₅^2- (Reactive Inorganic Sulfur Species, RISSs) were clarified in the absorption (colorimetric) and fluorescence (ratiometric) spectra, which showed good stability in the physiological pH (7.4). Upon the analytes, the maxima absorption of CH-RISSs switched from ~580 nm to ~400 nm in the absorption spectra. The fluorescence of CH-RISSs depleted at 650-660 nm and increased at 480-505 nm upon the RISSs. Both of coumarin hemicyanine structures with C12 alkyl chain (CH-RISS-3 and CH-RISS-6) showed quick and robust ratiometric fluorescence switch in the living cell imaging. Access to the fluorescent probes for RISSs sets the stage for applying the developing technologies to probe reactive sulfur biology in living systems.

Highly sensitive and rapid responsive fluorescence probe for determination of formaldehyde in seafood and in vivo imaging application

Mutagenic formaldehyde (FA) is usually abused to preserve seafood, thus it is very necessary to detect harmful formaldehyde in seafood with a simple and effective method. In this work, we facilely prepared a new fluorescent probe RBNA, which showed a remarkable fluorescence lighting-up response towards FA with high sensitivity and selectivity, fast response (within 5 min) and a low detection limit (0.21 μM). The fluorescence intensity is linearly related to the concentration of FA ranging from 0 to 120 μM (R² = 0.9952), which enables it to quantitatively determine the concentration of FA. This probe was successfully used to detect FA in seafood samples with good recoveries (80-119%). Furthermore, the probe has been utilized to image FA in living cells and zebrafish with good performance. Therefore, this probe has a good capability for rapid and sensitive determination of FA in seafood.

A novel benzothiadiazole-based and NIR-emissive fluorescent sensor for detection of Hg2+ and its application in living cell and zebrafish imaging

The probe TBBA exhibited excellent analytical properties with a remarkably large Stokes shift (195 nm), rapid response, high selectivity and sensitivity, good binding constant (2.37 × 10⁴ M⁻¹) and low LOD (13.10 nM).

A selective cascade reaction-based probe for colorimetric and ratiometric fluorescence detection of benzoyl peroxide in food and living cells

A novel colorimetric and ratiometric fluorescent probe (Cou-BPO) was readily prepared for specific detection of harmful benzoyl peroxide (BPO). The probe Cou-BPO reacted with BPO via a selective oxidation cleavage-induced cascade reaction of the pinacol phenylboronate group, which resulted in an observable colorimetric and ratiometric fluorescence response towards BPO with a fast response time (<15 min) and a low detection limit (56 nM). For practical application, facile, portable and sensitive test paper of Cou-BPO has been prepared for visual detection of BPO. Furthermore, we employed Cou-BPO as a probe to determine BPO in food samples and living cells.

Highly Sensitive Detection of Benzoyl Peroxide Based on Organoboron Fluorescent Conjugated Polymers

The method capable of rapid and sensitive detection of benzoyl peroxide (BPO) is necessary and receiving increasing attention. In consideration of the vast signal amplification of fluorescent conjugated polymers (FCPs) for high sensitivity detection and the potential applications of boron-containing materials in the emerging sensing fields, the organoboron FCPs, poly (3-aminophenyl boronic acid) (PABA) is directly synthesized via free-radical polymerization reaction by using the commercially available 3-aminophenyl boronic acid (ABA) as the functional monomer and ammonium persulfate as the initiator. PABA is employed as a fluorescence sensor for sensing of trace BPO based on the formation of charge-transfer complexes between PABA and BPO. The fluorescence emission intensity of PABA demonstrates a negative correlation with the concentration of BPO. And a linear range of 8.26 × 10⁻⁹ M–8.26 × 10^–4 M and a limit of detection of 1.06 × 10^–9 M as well as a good recovery (86.25%–111.38%) of BPO in spiked real samples (wheat flour and antimicrobial agent) are obtained. The proposed sensor provides a promising prospective candidate for the rapid detection and surveillance of BPO.

Sensitive Water-Soluble Fluorescent Probe Based on Umpolung and Aggregation-Induced Emission Strategies for Selective Detection of Hg2+ in Living Cells and Zebrafish

Using Hg²⁺-induced umpolung reaction and aggregation induced emission (AIE), we have rationally developed a water-soluble fluorescent probe 2,2'-(((4-(4,5-bis(4-methoxyphenyl)-1-phenyl-1H-imidazol-2-yl)phenyl)methylene)bis(sulfanediyl))diethanol (MPIPBS) for Hg²⁺ detection. MPIPBS was found to have high selectivity and sensitivity toward Hg²⁺ detection. The mechanism of MPIPBS response to Hg²⁺ was verified by ¹H NMR titration, HPLC, and HRMS spectroscopy. The detection limit was examined to be 1.45 nM, which is lower than most reported probes for Hg²⁺. Taking advantage of excellent optical properties of AIEgen, a paper based sensor for Hg²⁺ detection was fabricated by immobilizing the MPIPBS on Waterman test paper. Meanwhile, MPIPBS showed satisfactory analytical performance in real water and urine samples. Further, thanks to the high water solubility, cell membrane permeability and low cytotoxicity, MPIPBS was further used to detect Hg²⁺ both in living cells and zebrafish. We anticipate that the prepared probe was available to detect Hg²⁺ in environment and biosamples.

A selective cascade reaction-based probe for colorimetric and ratiometric fluorescence detection of benzoyl peroxide in food and living cells

A colorimetric and ratiometric fluorescent probe (Cou-BPO) was prepared for food analysis and cell imaging; it showed high selectivity, sensitivity, visible and fast response towards BPO via a selective oxidation cleavage-induced cascade reaction.

A selective cascade reaction-based probe for colorimetric and ratiometric fluorescence detection of benzoyl peroxide in food and living cells

A colorimetric and ratiometric fluorescent probe (Cou-BPO) was prepared for food analysis and cell imaging; it showed high selectivity, sensitivity, visible and fast response towards BPO via a selective oxidation cleavage-induced cascade reaction.

An aggregation-induced emission-based fluorescence turn-on probe for Hg2+ and its application to detect Hg2+ in food samples

In this work, we presented a new tetraphenylethene-derived fluorescent probe TPE-M for Hg²⁺ detection in an aqueous solution. Probe TPE-M is molecularly dissolved in CH₃OH/PBS (20 mM, pH = 7.4) (3 : 7, v/v) mixed solution and is almost non-emissive. Reaction of TPE-M with Hg²⁺ leads to release of an AIE-active precursor 4, and results in a significant fluorescence enhancement. The Hg²⁺ recognition process has some distinct advantages including rapid response, high selectivity and sensitivity, strong anti-interference ability, and a low detection limit (4.16 × 10⁻⁶ M). Moreover, the probe is applicable to detect Hg²⁺ in real food samples such as shrimp, crab and teas, suggesting the practical applicability of TPE-M.

A new AIE-based fluorescent probe TPE-M for Hg²⁺ detection in an aqueous solution has been developed.

A coumarin chalcone ratiometric fluorescent probe for hydrazine based on deprotection, addition and subsequent cyclization mechanism

A coumarin chalcone derivative with a levulinic acid terminal group acts as a ratiometric fluorescent probe for hydrazine based on deprotection, addition and a subsequent cyclization reaction mechanism.