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Sulfur and Nitrogen Co-Doped Graphene Quantum Dots as a Fluorescent Quenching Probe for Highly Sensitive Detection toward Mercury Ions
摘要： Sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs) were synthesized through an efficient infrared (IR)-assisted pyrolysis of glucose, urea, and ammonia sulfate at 260°C. These served as a highly selective probe for the sensing of Hg2+ ions in an aqueous solution. The IR technique can also prepare N-doped graphene quantum dots (N-GQDs), which have been compared with SN-GQDs for their fluorescence (FL) quenching sensitivities by Hg2+ ions. The FL intensities of both GQDs show decreasing functions of concentration of Hg2+ ions within the entire concentration ranges of 10 ppb?10 ppm. The sensitivity of SN-GQD is 4.23 times higher than that of N-GQD, based on the calculation of the Stern-Volmer equation. One inter-band gap structure of SN-GQDs for the detection of mercury ions is proposed. The S doping can coordinate with phenolic groups on the edge of SN-GQDs (i.e., the formation of (CxO)2Hg2+) and induce the cutting off or alleviation of photon injection paths, thereby leading to significant FL quenching. This work proves that SN-GQD offers sufficient sensitivity for probing the quality of drinking water to ensure that it contains less than 10 ppb of Hg2+ ions, as per the World Health Organization standard.
关键词： Fluorescence quenching,Nitrogen doping,Infrared-assisted heating,Graphene quantum dots,Sulfur doping,Mercury detection
更新于2025-11-19 16:56:42
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The Application of Green-Synthesis-Derived Carbon Quantum Dots to Bioimaging and the Analysis of Mercury(II)
摘要： Ginkgo leaves were used as precursors for the hydrothermal synthesis of carbon quantum dots (CQDs), which were subsequently characterized by transmission electron microscopy as well as Fourier-transform infrared, X-ray powder di?raction, and X-ray photoelectron spectroscopy. The prepared CQDs exhibited a ?uorescence quantum yield of 11% and superior water solubility and ?uorescence stability, as well as low cytotoxicities and excellent biocompatibilities with A549 and HeLa cells; these CQDs were also used to bioimage HeLa cells. Moreover, owing to the experimental observation that Hg2+ quenches the ?uorescence of the CQDs in a speci?c and sensitive manner, we developed a method for the detection of Hg2+ using this ?uorescence sensor. The sensor exhibited a linear range for Hg2+ of 0.50–20 μM, with an excellent coe?cient of determination (R2 ? 0.9966) and limit of detection (12.4 nM). In practice, the proposed method was shown to be highly selective and sensitive for the monitoring of Hg2+ in lake water and serum samples.
关键词： mercury(II) detection,carbon quantum dots,hydrothermal synthesis,fluorescence quenching,bioimaging
更新于2025-11-19 16:46:39
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Pyrene-SH functionalized OTFT for detection of Hg2+ ions in aquatic environments
摘要： Mercury ion (Hg2+) sensor based on bottom gate top contact organic thin film transistor (OTFT) was fabricated. The OTFT channel area was functionalized with pyrene that contain thiol group, which has strong binding affinity toward Hg2+ ion. The OTFT sensor exhibited a charge mobility of 0.28 cm2 V–1 s–1, a threshold voltage of -22.3 V and on-to-off ratio 103. The sensor shows high selectivity to Hg2+ ion over other two valence metal ions. OTFT sensor exhibited high sensitivity to Hg2+ ion, indicated by increasing of drain current after exposed to different concentration of Hg2+ ion ranging from 1 mM to 0.01 μM. Moreover, the OTFT sensor capability for practical application was also demonstrated by sensing the present of 25 μM of Hg2+ ion in tap, drinking and seawater samples.
关键词： Mercury sensor,Pyrene derivative,Organic thin film transistor
更新于2025-11-14 17:28:48
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One-Dimensional Mercury Halide Coordination Polymers Based on A Semi-Rigid N-Donor Ligand: Reversible Structural Transformation
摘要： Four one-dimensional (1D) mercury(II) halide coordination polymers have been synthesized by using a semi-rigid N-donor ligand, 2,2′-(1,4-phenylene)-bis(N-(pyridin-3-yl)acetamide) (1,4-pbpa). While [Hg(1,4-pbpa)Cl2·CH3OH]n, 1, forms a sinusoidal chain, the complexes [Hg(1,4-pbpa)X2]n (X = Cl, 2; Br, 3; I, 4) are helical. The sinusoidal 1 undergoes reversible structural transformation with helical 2 upon removal and uptake of CH3OH, which was accompanied with the conformation adjustment of the 1,4-pbpa ligand from trans anti-anti to trans syn-anti. Pyridyl ring rotation of the 1,4-pbpa ligand that results in the change of the ligand conformation is proposed for the initiation of the structural transformation.
关键词： mercury halide,structural transformation,bis-pyridyl-bis-amide,coordination polymer
更新于2025-11-14 15:13:28
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Enhanced photocatalytic activity of TiO2/graphene by tailoring oxidation degrees of graphene oxide for gaseous mercury removal
摘要： We used a simple method of graphene oxide (GO) preparation with different oxidation levels, and control the properties of the TiO2 nanocrystals by tuning the content and oxidation degree of GO to enhance the photocatalytic performance. During the hydrothermal reaction, reduction of GO, formation of TiO2 and chemical bonds between TiO2 and reduced graphene oxide (RGO) was achieved simultaneously. Characterization results showed that TiO2 properties such as crystalline grain and particle size could be tailored by the amount of functional groups, and that crystallinity was also controlled by GO degrees of oxidation. TiO2/RGO photocatalysts showed great efficiency of mercury oxidation, which reached 83.7% and 43.6% under UV and LED light irradiation, respectively. The effects of crystalline grain size and surface chemical properties on Hg0 removal under LED and UV light irradiation were analyzed. In addition, the properties of the photocatalysts before and after UV illumination were investigated, finding that part of Ti-OH on TiO2 surface transformed to Ti-O-Ti. In a nutshell, this work could provide a new insight into enhancing activity of photocatalysts and understanding the photocatalytic mechanism.
关键词： TiO2,Photocatalysis,Chemical Bonds,Elemental Mercury,Reduced Graphene Oxide
更新于2025-09-23 15:23:52
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A Simple Rhodanine-Based Fluorescent Sensor for Mercury and Copper: The recognition of Hg2+ in aqueous solution, and Hg2+/Cu2+ in organic solvent
摘要： Detection of copper and mercury attracts important in most environmental and biological systems. In this study, the simple probe 2-OxI-Rh containing rhodanine core was synthesized by a green approach and sensing properties were studied using colorimetric and fluorometric detection. The research indicated that the specific ion affinity for Hg2+ ions in aqua systems and the multi-ion affinity for Hg2+ and Cu2+ in organic solvent results in drastic color and spectral changes. According to the data obtained, while the peak intensity increases at 390 nm, the peak intensity decreased at 272 nm in the absorption spectrum of 2-OxI-Rh and an increase in fluorescence intensity of 2-OxI-Rh were observed in the presence of Hg2+ and Cu2+ ions. The binding ratio of 2-OxI-Rh to Hg2+ and Cu2+ were found to be 1:1 according to Job's plot experiments. The binding constants were calculated using the Benesi-Hildebrand equation and found to be 2.15×104 M?1 for Hg2+ and 1.21×104 M?1 for Cu2+. Based on these concentration dependent fluorescence changes, the limit of detection (LOD) values were also calculated and found to be 3.36 μM for Hg2+ and 2.31 μM for Cu2+, which is the range of copper that should be in the blood (11.8–23.6 μM). As a result of all these studies, we can understand that prove 2-OxI-Rh, which is non-toxic, is a good selective candidate turn-on sensor that can be used for Hg2+ and Cu2+ detection in different solvent systems.
关键词： oxindole,Rhodanine,colorimetric,turn-on sensor.,mercury,chemosensor,copper
更新于2025-09-23 15:23:52
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Colorimetric and turn-on Fluorescence Chemosensor for Hg2+ Ion Detection in Aqueous Media
摘要： A new rhodamine 6G based fluorescent and colorimetric chemosensor, containing N-methyl imidazole nucleus, for the selective detection of Hg2+ ion was designed and synthesized. The results of UV-Vis and fluorescence spectral study indicated that the receptor is selective and sensitive towards Hg2+ with no noticeable interference with other competitive metal ions. The addition of Hg2+ to the receptor induced a rapid color change to pink from colorless and the turn-on fluorescence response toward Hg2+ among different cations was studied. The stoichiometric ratio of 1:1 between the receptor and Hg2+ was supported by Job’s plot. The color change and turn-on fluorescence response upon addition of Hg2+ ion was ascribed by the spirolactam ring-opening mechanism. The probable mode of binding between the receptor and Hg2+ was confirmed by 1H NMR and Mass spectral study. For the practical application, its electrospun nanofiber test strips successfully applied to recognize Hg2+ ion in aqueous media.
关键词： Sensing,Mercury ion,Nanofiber,Fluorescent
更新于2025-09-23 15:23:52
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BELA transmitter performance and pointing stability verification campaign at DLR-PF
摘要： BELA is the first European planetary laser altimeter and shall be launched onboard of ESA's Mercury Planetary Orbiter (MPO) as part of the BepiColombo spacecraft in October 2018. The complete development of the instrument was done in collaboration with team members in Switzerland, Germany and Spain. The transmitter is also the first space-qualified laser system for a planetary mission built in Europe. Highly important for scientific performance is the transmitter's performance which is specified with demanding values. Thermo-optical pointing stability, alignment, pulse energy, wavelength, pulse profile and length have a direct impact on the signal quality and strength of the instrument and in consequence on the quality of science data. Furthermore for in-orbit operation the detailed knowledge of the transmitter behavior is required for the interpretation of measurement data. Therefore the transmitter, an encapsulated diode pumped pulsed Nd:YAG laser, was extensively tested at facilities at DLR in Berlin-Adlershof under various environmental conditions in all possible representative configurations. This is necessary because thermo-elastic and optical behavior are difficult to predict accurately only theoretically. Furthermore there are temperature dependent effects, e.g. for laser energy, which directly affect science measurements and can only be calibrated on-ground. An optical test bench was designed and set up for this particular task. This work describes the test bench and the measurement procedures. The measurement results for the Engineering Qualification Model and Flight Model are presented and discussed as well as lessons learned. The outcome of the tests shows that the BELA FM transmitter performs well with margins and BELA is expected to achieve its scientific goals.
关键词： Laser altimeter,BELA,Transmitter,Verification,BepiColombo,Mercury
更新于2025-09-23 15:23:52
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Novel SPR sensing platform based on superstructure MoS2 nanosheets for ultrasensitive detection of mercury ion
摘要： Water contamination by Hg2+ and its detection have attracted much attention. However, the detection limit for Hg2+ by traditional techniques is 200 pM, which is far higher than the maximum Hg2+ concentration allowed in effluent (7.5 pM). Here, we developed a novel surface-plasmon-resonance (SPR) sensor for Hg2+ detection by using superstructure MoS2 nanosheets as the sensing layer material. The simulations and structural characterizations reveal that the ultra-high sensitivity of the SPR sensor arises from the large interlayer spacing and sufficient unsaturated bonds in MoS2 superstructure, which promotes transporting and adsorbing Hg2+. Surprisingly, the Hg2+ detection limit of the SPR sensor is as low as 1.0 pM, which is 200 times lower than those of existing Hg2+ sensors. Therefore, our research presents an effective method for detecting ultra-low concentration of Hg2+ and also reveals the sensing mechanism of MoS2 – based SPR sensor. This not only extends the application of superstructure MoS2 nanosheets, but also provides a novel design idea for the development of ultra-sensitive detection technologies.
关键词： surface plasmon resonance,biosensor,superstructure,MoS2,mercury
更新于2025-09-23 15:22:29
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OPTically-based In situ Characterization System (OPTICS) to quantify concentrations and mass fluxes of mercury and methylmercury in South River, Virginia, USA
摘要： Historical releases of mercury to the South River (Virginia, USA) and mobilization of mercury from secondary sources (e.g., riverbed and riverbank sediments) is contributing to the redistribution of mercury to the water column. Therefore, in order to effectively remediate the South River, it is necessary to understand specific mechanisms for mercury contamination and transport in the system. An OPTically‐based In situ Characterization System (OPTICS) monitoring study was conducted to quantify concentrations and mass fluxes of mercury and methylmercury and to understand mechanisms of contaminant exchange between sediments and the water column. Storm flow and diel cycling (potentially related to nocturnal bioturbation activities) were identified as important mechanisms of particulate‐phase mercury and methylmercury exchange to the South River water column. It was determined that diel cycling contributed daily average mass transport of 0.01 kg of particulate mercury and 1.9E‐05 kg of particulate methylmercury, representing up to 13% and 16% of total mercury and methylmercury mass transported over the study period. Approximately 85% of the 3.6 and 0.01 kg total mass transport of particulate mercury and methylmercury over the study period was attributed to high storm flow, which likely resulted in resuspension of particle‐bound mercury and methylmercury and/or mobilization of fine‐grained channel margin deposits.
关键词： optical monitoring,mass fluxes,methylmercury,mercury,South River
更新于2025-09-23 15:22:29