Search

Due to its high toxicity, long durability, easy absorption by aquatic organisms, and significant bioaccumulation, Hg2+ has caused substantial environmental damage and posed serious threats to human health. Therefore, effective detection of Hg2+ is of utmost importance. In this study, a turn-on fluorescent probe based on dicyanoisoflurone was developed for the detection of Hg2+. The probe exhibited near-infrared fluorescence signal at 660 nm upon excitation by 440 nm UV light in a mixture of CH3CN and HEPES buffer (4:1, v/v, 10 mM, pH = 7.5), with selective binding to Hg2+ in a molar ratio of 1:1. This binding event was accompanied by a visible color change from light yellow to orange. By utilizing the enhanced fluorescence signal change, this probe enables highly sensitive analysis and detection of Hg2+ with excellent selectivity (association constant = 1.63 × 104 M− 1), large Stokes shift (220 nm), high sensitivity (detection limit as low as 5.6 nM), short reaction time (30 s), and a physiological pH range of 7.5–9.5. The probe was successfully employed for detecting of Hg2+ in real water and living cells. [ABSTRACT FROM AUTHOR]

Near-infrared organic small molecule luminescent materials have the advantages of easy modification, high quantum efficiency, good biological affinity, and color adjustability; thus, have promising application prospects in the fields of photoelectric devices, sensitive detection, photodynamic therapy, and biomedical imaging. However, traditional organic luminescent molecules have the problems of short emission wavelength, aggregation-causing emission quenching, and low quantum yield. Herein, we successfully synthesized four D-π-A-D light-emitting molecules based on electron-withdrawing malonitrile group and different electron-donating arylamine groups. These compounds showed satisfactory solvatochromism, aggregation-induced emission, red and near-infrared fluorescence, high photoluminescence quantum efficiency and temperature response properties. This successful example of molecular engineering provides a valuable reference for the development of advanced NIR materials with AIE and temperature-sensitive properties. [ABSTRACT FROM AUTHOR]

Hypochlorite (ClO−) is closely involved in human health and environmental safety. Therefore, it is of vital importance to realize the detection and separation of ClO−. Herein, a nanoprobe with analysis and removal capabilities of ClO− was synthesized via immobilizing coumarin-based functional molecules on halloysite nanotubes. The probe can easily detect ClO− in aqueous solution without the need for organic solvents, showing a fast detection time (10 s), a wide pH range (4–11), a low detection limit (8.4 nM), and a credible recovery rate range of 93.6–105.1%. The probe was further prepared into convenient test papers to realize the visual detection of ClO−. More importantly, it also enabled the removal of ClO−, and the removal rate was as high as 99.6%. [ABSTRACT FROM AUTHOR]

Endogenous carbon monoxide (CO) is an important intracellular gas messenger that is intimately involved in many physiological and pathological processes. The abnormal concentration of CO in living organisms can cause many diseases. Therefore, it is of great significance to monitor CO in biological samples. Fluorescent probe technology provides an effective and convenient method for CO monitoring, with the advantages of high selectivity and sensitivity, fast response time and in situ fluorescence imaging in biological tissues, which is favored by the majority of researchers. In this paper, the research progress of CO fluorescent probes since 2018 is reviewed, and the design, detection mechanism and biological application of the related fluorescent probes are summarized. And the relationship between the structure and performance of the probes is discussed. Furthermore, the development trend and application prospect of CO fluorescent probes are prospected. [ABSTRACT FROM AUTHOR]

Ascorbic acid (AA) determination is of high importance in the diagnosis and treatment of diseases. Herein, we report a new ratiometric electrochemical sensor for ascorbic acid using a glassy carbon electrode (GCE) modified with a copper nanoparticle@resin nanosphere nanocomposite (CuNPs@RNS). The ratiometric strategy was established by immobilizing an internal reference (thionine) on the modified electrode using cyclic voltammetry (CV). The performance of the modified electrodes as well as the newly established ratiometric strategy was explored. The sensing platform had good electrocatalytic ability, reproducibility, and stability. In addition, the ratiometric strategy significantly improved the performance of electrochemical sensing with a wide linear range (0.0837 to 15.5 μM) and a low detection limit of 0.0279 μM under the optimal conditions. The original ratiometric electrochemical sensor was successfully applied to monitor ascorbic acid in tablets and urine. These results showed that the sensor provides a new strategy and broad prospects for biomolecular sensing with reliability and high sensitivity. [ABSTRACT FROM AUTHOR]

It is an effective way to utilize low-rank coal to obtain Hyper-coal by thermal extraction. Taking Shanxi lignite as raw material, the Hyper-coal was obtained by extraction at several temperatures. The basis of Hyper-coal as an excellent upgrading binder for coking was comprehensively studied from two aspects of macrocohesion index and microstructure. The experimental results show that the content of ash and sulfur in the Hyper-coal is low, and the content of light components is increasing with the increase of extraction temperature. The thermoplasticity of hyper-coal is generally high, the fluidity of colloid formed by pyrolysis is higher than that of conventional coking coal, and the bonding ability also reaches the level of fat coal. The source of high thermoplasticity of hyper-coal mainly depends on its microstructure, such as high aliphatic hydrocarbon content and wide thin compact carbon network structure. The optimum extraction temperature was 380°C. Generally speaking, Hyper-coal can be used as an excellent binder for coking. [ABSTRACT FROM AUTHOR]

As one of the important metal ions, zinc ions (Zn2+) are widely involved in various physiological and pathological processes, and play fundamental roles in neurotransmission, cell metabolism and apoptosis. However, the convenient monitor of Zn2+ in environmental and biological samples remains challenging. In this study, a small molecule dicyanoisophorone-based schiff base incorporating with o-phenylenediamine was synthesized. It can rapidly combine with Zn2+ to emit significant near-infrared fluorescence (maximum emission wavelength: 660 nm), so it can be used as a probe to quantitatively detect Zn2+ in the range of 0–10 μM, with a detection limit as low as 4.8 nM, showing the probe has high sensitivity for Zn2+. And the probe has a fast response time to Zn2+ (less than 30 s) and a large Stoke-shift (179 nm). In addition, the high recovery rates in practical water samples, and the clear fluorescent images in living A549 cells were obtained, which are of great significance for the detection of Zn2+ in the environment and biosystem. Due to its simple operation, good selectivity and anti-interference ability, short detection time and high sensitivity, this probe has great application potential as a fast detection tool for Zn2+ in environmental water and biological samples. [ABSTRACT FROM AUTHOR]

Iron and titanium doped γ-Al2O3 (γ-Fe-Ti-Al2O3) mesoporous catalysts were synthesized by evaporation-induced self-assembly using glucose as template, and applied to ozonation of ibuprofen in bromide-containing water. X-ray diffraction (XRD), nitrogen adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS) results showed that iron and titanium successfully doped into the skeleton of γ-Al2O3, uniform distribution, maintain the ordered mesoporous structure of γ-Al2O3, with larger specific surface area. The valence of titanium coexists with Ti4+ and Ti3+, and the valence of iron was Fe3+. Infrared spectra of chemisorbed pyridine (Py-FTIR) results showed that the doped titanium and iron into the framework position of γ-Al2O3 altered the surface acidity of the alumina surface, especially increasing the medium Lewis acid sites, which was conducive to the effective decomposition of ozone into active oxygen species. The γ-Fe-Ti-Al2O3 catalyst (Al/Fe = 25, Al/Ti = 75) enhanced the removal rate of ibuprofen in ozonation of bromide-containing water, and effectively blocked the formation of bromate. After the reaction of 60 min, the removal rate of TOC was increased from 54% of γ-Al2O3/O3 to 86% with γ-Fe-Ti-Al2O3/O3, while the ozonation alone was only 13%. Electron Paramagnetic Resonance (EPR) spectra showed that hydroxyl and superoxide radicals were reactive oxygen species, which was beneficial to the mineralization of organic matter. The capture experiment of Fe2+ ion confirmed that the electronic cycle of Fe2+ ion and Fe3+ ion was beneficial to block the formation of bromated. The addition of ibuprofen and humic acid can enhance the reduction of Fe3+ in the catalytic ozonation of γ-Fe-Ti-Al2O3, which further strengthened the blocking of bromate formation. [ABSTRACT FROM AUTHOR]

In this work, antimicrobial agent polylysine was deliberately used to functionalize carbon nanotubes and activated carbon to load antimicrobial enzyme lysozyme. Antimicrobial activity of the loaded lysozyme on polylysine-functionalized carbon materials was significantly enhanced, and the functionalizing agent exhibited its own apparent antimicrobial activity as well. Remarkably, antimicrobial ɛ-polylysine synergistically enhanced antimicrobial activity of loaded lysozyme on its functionalized carbon nanotubes to more than five times as high as the activity of free lysozyme in solution, in sharp contrast to that of loaded lysozyme on unfunctionalized carbon nanotubes or activated carbon, or functionalized activated carbon. The actual antimicrobial activity of loaded lysozyme on functionalized carbon nanotubes was applied with Bacillus subtilis, exhibiting much faster digesting lysis of the bacteria in comparison with free lysozyme. The results indicate that polylysine on carbon nanotubes played a dual role as the functionalizing and antimicrobial agent as expected. Synergistic and potent antimicrobial activities from combined action of antimicrobial enzyme and antimicrobial agent on carbon nanotubes provide a new antimicrobial protection for food and beverage industry and other biochemical processes. [ABSTRACT FROM AUTHOR]

With the widespread use of N2H4, it brings potential risk to human health and environmental safety because of its diverse toxicological functions. In order to determine N2H4 effectively in both environment and living systems, all kinds of fluorescence probes have been prepared for the specific response of N2H4 based on various mechanisms and different acceptor group for N2H4. This paper provides a review to bring more inspirations for the development of the fluorescent probes for N2H4. [ABSTRACT FROM AUTHOR]

Hydrazine is widely used in fuels, fuel cell reactors and the synthesis of polymer, drug and pesticide intermediates. However, it can be contained in food and drinking water and enter organisms through the food chains because of its good water solubility, causing serious health problems. Therefore, there is an urgent need to develop new analytical reagents to detect hydrazine with high selectivity and sensitivity. In this paper, a spectroscopic probe (probe 1) for hydrazine hydrate based on the addition‐cyclization mechanism with high selectivity and sensitivity was developed. This probe can simultaneously detect hydrazine by UV‐visible and fluorescence spectra, and the corresponding detection limits are 51.7 μM and 6.7 nM, respectively. Importantly, the spectroscopic probe was successfully applied to hydrazine detection in water samples and living cells. The test strips based on the probe was also prepared for the point‐of‐care testing of hydrazine in the actual water samples.A dual spectroscopic benzothiazole‐based probe based on the addition cyclization reaction mechanism has been developed, which can effectively detect hydrazine (N2H4) in water samples and living cells by UV‐visible and fluorescence spectra, and can be prepared as the convenient test paper to detect hydrazine hydrate. This probe provides a reliable testing method for N2H4. [ABSTRACT FROM AUTHOR]

Zinc ion is closely related to human health. Its content in human body is small, while the effect is large. However, it is not the more the better, must be in a scientific balance. Therefore, it is significant to the rapid detection of Zn2+ in the environment and organism. Herein, a fluorescent probe based on 2-hydroxy-1-naphthalene formaldehyde and furan-2-carbohydrazide was conveniently synthesized via Schiff base reaction. And this probe has been successfully applied to the accurate and quantitative detection of Zn2+ in real samples, showing turn on fluorescence, good selectivity, very low detection limit, real time response and reusability. In addition, this probe has the potential application to trace Zn2+ in living cells with low cytotoxicity. [ABSTRACT FROM AUTHOR]

Hydrosulphite (HSO3−), as a common and important chemical reagent, is widely used in everyday life, however excessive use and abuse of HSO3− can cause potential harmful effects on the environment and in biological health. In this paper, we describe the design and preparation of a colorimetric and ratiometric fluorescence probe for the visual detection of HSO3− (excitation wavelengths were, respectively, 336 nm and 520 nm). This method showed some advantages including simple preparation, high selectivity, fast response, and significant colour and fluorescence ratio (F450/F594) changes in the presence of HSO3−. In addition, this probe was used successfully for the detection of HSO3− in real water samples and showed a good recovery rate range. [ABSTRACT FROM AUTHOR]

Hypochlorite (ClO−) mediated by oxidative stress play an important role in the body's defense system due to their physiological and pathological significance. In this work, a new and simple probe was designed and synthesized to detect hypochlorite. This probe could rapidly respond to hypochlorite in a short time (20 s) in aqueous media, and showed excellent selectivity and sensitivity, and a wide pH range of 3 ̶ 12, as well as the low detection limit of 1.44 nM. In addition, it was successfully applied to the detection of ClO− in water sample, test paper experiment, and cell imaging. [ABSTRACT FROM AUTHOR]

Endogenous carbon monoxide (CO) is an essential cell signaling molecule, which is closely related to numerous physiological and pathological processes. Therefore, it is of great significance to monitor CO in living samples. Fluorescent probe technique provides an effective and convenient method for monitoring CO. Although many fluorescent probes of CO have been reported, most of them require the introduction of heavy metal ions (Pd2+), which is not conducive to the practical application of these probes. Herein, a metal-free coumarin-based fluorescent probe was developed for monitoring CO. For this probe, coumarin was selected as the fluorophore, the aromatic nitro group was used as the reactive site, and the carboxyl moiety acted as the water-soluble unit. As a result, this probe has been proved to be able to monitor CO with good specificity and excellent sensitivity in water medium. After interacting with CO, the aromatic group was reduced to an aryl amino group; accordingly, the emission intensity of the peak corresponding to the probe at 450 nm significantly increased. Moreover, it successfully realized the detection of CO in living cells by a fluorescence signal. [ABSTRACT FROM AUTHOR]

A turn on fluorescence probe was designed cleverly and synthesized simply through the condensation reaction between coumarin derivative and barbiturate, for sensitively specific recognition of hypochlorite ion (ClO−). This probe displayed a transient monitor process (about 5 min) to ClO− in a wide range of pH values (3‐10), and the monitor limit could be estimated as low as 0.73μM. What's more, this probe could perform fluorescence imaging of ClO− in living cells, and make ClO− in aqueous solution appear on the convenient test strip visually. [ABSTRACT FROM AUTHOR]

A Schiff's base derivative was synthesized using a condensation reaction between 8‐formyl‐7‐hydroxy‐4‐methylcoumarin and furan‐2‐carbohydrazide that produced marked aggregation‐induced emission and had excellent ability to specifically recognize aluminium ions (Al3+). This compound displayed faint fluorescence in the benign solvent dimethyl formamide, and exhibited obvious green fluorescence following addition of specific amounts of water. Moreover, it exhibited strong blue fluorescence after combination with Al3+ even in the presence of other interfering ions. These experimental results demonstrated that this derivative could be used as a fluorescence probe for Al3+. The advantages, including significant fluorescence change, high selectivity and sensitivity, and fast response, meant that this probe could be used both to detect Al3+ in water samples and for fluorescence imaging in living cells. [ABSTRACT FROM AUTHOR]

Development of optical probe for the detections of Fe3+ and Cu2+ is one of the most active and interesting research directions in analytical chemistry because of their vital roles in the environment protection and human health. Herein, a turn on optical rhodamine B-based probe (probe 1) with the significant changes in color and fluorescence has been prepared. The color of this probe solution changed from colorless to amaranth in the presence of Fe3+ and to pink in the presence of Cu2+, which is promising for the qualitative recognition of Fe3+ and Cu2+. More importantly, probe 1 could be used for the quantitative analysis of Fe3+ and Cu2+ by fluorescence enhancement. The detection limits for Fe3+ and Cu2+ reached 8.1 × 10−8 M and 4.8 × 10−7 M, respectively. Furthermore, it was found that this probe can also be used for fluorescence imaging of Fe3+ and Cu2+ in living cells. [ABSTRACT FROM AUTHOR]

A turn on fluorescence probe for the rapid detection of hypochlorite (ClO−) was prepared successfully. The detection performances of this probe were studied by virtue of ultraviolet absorption and fluorescence spectroscopy. The results demonstrated that this probe displayed excellent colorimetric and noteworthy fluorescence enhancement after interaction with hypochlorite (ClO−) and showed good selectivity and sensitivity for ClO− over other analytes in solution. Due to the short reaction time, high selectivity and sensitivity, this probe was successfully used in the detection of ClO− in living cells and water samples. [ABSTRACT FROM AUTHOR]

A magnetically recyclable metal organic composite (FeOCPc@Ni) was successfully prepared by a simple hydrothermal method and was characterised by FTIR spectroscopy, XRD, SEM, VSM and specific surface area and porosity analysis. More importantly, FeOCPc@Ni showed excellent photo-degradation performances for methyl orange (MO) under acidic conditions and of p-nitrophenol (PNP) under alkaline conditions. The degradation rates of MO and PNP were greater than 97.91% and 97.99%, respectively. In addition, after being reused 10 times, the degradation rates of MO and PNP respectively were 88% and 85%, showing good recyclability and reusability. [ABSTRACT FROM AUTHOR]

Smart and versatile salicylaldehyde Schiff's bases have been proved their excellent performances including large shocks shift, dual emission wavelengths and sensitive to environment for fluorescence analysis. Herein, a simple salicylaldehyde Schiff's base molecular (PBAS) with aggregation-induced emission (AIE) and the excited-state intramolecular proton-transfer (ESIPT) effects was constructed for detecting N2H4 and ClO−. The highly specific and sensitive response to N2H4 was witnessed by the fast turn-on of the strong blue fluorescence and to ClO− was observed by the rapid turn off of the weak green fluorescence simultaneous decomposing of the probe. The results of mass spectrum analysis showed that probe PBAS decomposed under the influence of N2H4, whereas probe PBAS can complex with ClO− and prevent effective ESIPT process. Benefiting from its high properties, this fluorescence molecular provides an effective tool for probing N2H4 and ClO− in live cells. [ABSTRACT FROM AUTHOR]

A simple Schiff base was prepared by mild condensation reaction between a coumarin fluorescent group and diaminomaleonitrile, and it could serve as an excellent fluorescent probe for fast detection of ClO− with high selectivity and sensitivity. Along with addition of ClO−, this probe fleetingly showed noteworthy “turn-on” phenomenon accompanied by an increase of fluorescence intensity and the change of emission color from yellow to blue. This change of fluorescence is so significant that it can be observed by the naked-eye under a handheld ultraviolet light of 365 nm. However, other common reactive oxygen species exhibited no or very little fluorescent response under the same conditions. The limit of detection of this probe toward ClO− had a sensitivity feature as low as 9.6 nM. On account of these excellent features of short response time, remarkable fluorescence and color signal changes, high sensitivity and selectivity, this probe was effectively used for the fluorescence detection of ClO− in water samples. The values of the relative standard deviation were between 1.41% and 2.91%. More importantly, this probe displays excellent imaging capability in cytoplasm as well as very low cell toxicity and was unambiguously applied to image ClO− in living cells.A fluorescent probe based on coumarin for detection of ClO- was successfully developed, which can besuccessfully used for the detection of ClO− in living cells and in water sample because of the excellentfeatures including short response time, remarkable fluorescence and color signal changes, high sensitivityand selectivity [ABSTRACT FROM AUTHOR]

Abstract: A multichannel fluorescence probe 8‐((((7‐(diethylamino)‐2‐oxo‐2H‐chromen‐3‐yl)methylene)hydrazono)methyl)‐7‐hydroxy‐4‐methyl‐2H‐chromen‐2‐one (probe 1) with “turn on” characteristics for selective and sensitive response toward Al3+, Hg2+ and ClO− was developed by mild condensation reaction of coumarin and ethanediamine. The probe could recognize Al3+, Hg2+ and ClO− with obvious change of fluorescence intensity in different mixture solution, and showed different maximum emission wavelengths in the presence of Al3+, Hg2+ and ClO− at 459 nm, 485 nm and 504 nm, respectively. More importantly, this probe has successfully been used in the monitoring of Al3+, Hg2+ and ClO− in tap water samples, and was resoundingly carried out imaging ClO− in living cells. [ABSTRACT FROM AUTHOR]

In this work, the positively-charged polymer polyethyleneimine was used to functionalize carbon nanotubes and activated carbon to load antimycotic enzyme lyticase. Interestingly, polyethyleneimine played a dual role functionalizing carbon materials to synergistically enhance antimycotic activity of loaded lyticase as well as exhibiting its own apparent antimycotic activity, where the enhanced enzymatic activity of loaded lyticase on functionalized carbon nanotubes was more than 2.8 times as high as the activity of free enzyme in solution. The actual activity of loaded lyticase on functionalized carbon nanotubes was applied with Penicillium janthinellum, exhibiting much faster digesting lysis of the bacteria in comparison with free lyticase. The synergistic and potent antimycotic activities from combined action of antimycotic lyticase and polyethyleneimine on carbon nanotubes provides a new antimycotic protection for medicine, food industry, and other biochemical processes. [ABSTRACT FROM AUTHOR]

A transformation process of ozone on different iron oxides suspensions, including α-Fe2O3, α-FeOOH, Fe3O4, was carried out using FTIR of adsorbed pyridine, ATR-FTIR and electron paramagnetic resonance (EPR) spectra with isotope 18O3. It was verified that on the surface isolated hydroxyl groups and the surface hydroxyl groups without acid sites of these iron oxides, ozone was electrostatically adsorbed and did not interact with the surface of these oxides, stably existed as ozone molecule. In contrast, ozone could replace the surface hydroxyl groups on Lewis acid sites of oxides, and directly interacted with the surface metal ions, decomposing into reactive oxygen species (ROS) and initiating the surface metal redox. The results indicate that Lewis acid sites were active center while the electronic cycle of the Fe2+/Fe3+ is advantageous to promote ozone decomposition into O2•− and •OH radicals. The mechanism of catalytic ozonation in different surface acid sites of iron oxides aqueous suspension was proposed on the basis of all experimental information. [ABSTRACT FROM AUTHOR]