Addition Of Hg2 Research Articles

Ratiometric fluorescence detection of Hg2+ based on gold nanocluster/carbon quantum dots nanohybrids.

Ratiometric fluorescence sensing methods are widely used in analysis and detection due to their high sensitivity and stability. In this work, a ratiometric fluorescence method for sensitive detection of Hg2+ was established using a gold nanoclusters/carbon quantum dots (AuNCs/CQDs) nanohybrid probe. The AuNCs/CQDs nanohybrids probe were simply constructed by mixing blue-light-emitting gold nanoclusters (AuNCs) with an orange-emissive carbon quantum dots (CQDs). The probe had two fluorescence emission peaks at 434 nm and 561 nm when the excitation wavelength was 375 nm. With the addition of Hg2+, the fluorescence at 434 nm decreased and the fluorescence at 561 nm remained unchanged; the fluorescence intensity ratio Δ(F434/F561) and Hg2+ concentration have a good linear relationship in the range of 8.32 × 10-7 to 7.69 × 10-5 mol L-1, and the limit of detection (LOD) is 3.58 × 10-7 mol L-1. The method was applied in the detection of Hg2+ in cosmetics and wastewater, and has potential applications for detecting Hg2+ in other samples.

Phosphorescent iridium(III) complexes containing bis(diphenylphorothioyl)amide ligands for the detection of Hg2+ ions and cysteine

Four iridium(III) complexes (L1)2Ir(stpip) (Ir1, L1 = 4-(trifluoromethoxy)phenylpyridine), (L2)2Ir(stpip) (Ir2, L2 = 2-(4-bromophenyl)pyridine), (L3)2Ir(stpip) (Ir3, L3 = 4-(2-pyridinyl)benzaldehyde), and (L4)2Ir(stpip) (Ir4, L4 = 6-(4-formylphenyl)nicotinaldehyde) using bis(diphenylphorothioyl)amide (stpip) as ancillary ligands were synthesized and fully characterized. Complexes Ir1−Ir4 exhibited blue to red emission with peaks ranging from 481 nm to 600 nm, all of which showed high photoluminescence quantum yields of 0.40–0.73. Upon addition of Hg2+ ions to the acetonitrile solutions of Ir1−Ir4, all these complexes displayed photoluminescence quenching and blue shift of the emission peaks, showing high selectivity. The detection limit for Hg2+ ions was as low as 10−8 M and that allowed monitoring Hg2+ ions in real water samples. Furthermore, Ir3 and Ir4 containing aldehyde groups showed remarkable specificity and anti-interference ability in the detection of cysteine (Cys). The reaction-type mechanism in sensing Hg2+ ions and Cys using these iridium complexes was studied in detail.

Constructing an eco-friendly and ratiometric fluorescent sensor for highly efficient detection of mercury ion in environmental samples.

Mercury ion (Hg2+) is a highly toxic and ubiquitous pollutant, whose effective detection has aroused widespread concern. A novel ratiometric fluorescent sensor has been designed to rapidly and efficiently detect Hg2+ based on blue/red carbon dots (CDs) with environmental friendliness. This sensor was well characterized via TEM, FTIR, XPS, UV-vis, and zeta potential analysis and displayed excellent fluorescence properties and stability. The fluorescence of blue CDs at 447nm was significantly quenched with the addition of Hg2+ resulted from the static quenching, whereas that of red CDs at 650nm remained invariable. A sensitive method for Hg2+ determination was constructed in the range of 0.05-7.0nmolmL-1 with optimal conditions, and the detection limit was down to 0.028nmolmL-1. Meanwhile, compared to other 17 metal ions, the ratiometric fluorescent sensor exhibited high selectivity for Hg2+. Furthermore, satisfied recoveries had also been obtained for measuring trace Hg2+ in practical environmental samples. This developed ratiometric fluorescent sensor provided a reliable, environmental-friendly, rapid, and efficient platform for the detection of Hg2+ in environmental applications.

Portable smartphone-assisted highly sensitive detection of mercury ions based on gold nanoparticle-modified NH2-UiO-66 metal-organic framework.

A novel portable smartphone-assisted colorimetric method was reported for the determination of Hg2+ with good analytical performance. AZr(IV)-based metal-organic framework functionalized with amino groups(NH2-UiO-66) has been adopted as asupporting platform to anchor gold nanoparticles (AuNPs), avoiding the migration and aggregation of AuNPs. With the addition of Hg2+, the formation of gold amalgam proved possible to enhance peroxidase-like activity of the composite (AuNPs/NH2-UiO-66), accelerating the oxidization of zymolyte 3,3',5,5'-tetramethylbenzidine (TMB). In the meantime, the color of the reaction solution turned a vivid blue, and the red, green, and blue (RGB) values of the solution color changed accordingly. On account of this strategy, the quantitative detection of Hg2+ could be achieved. After the optimization of the experiment conditions, the average color intensity (Ic) resulting from RGB values was linear related to the concentration of Hg2+ from 10 to 100nM, accompanied with a detection limit (LOD) down to 5.4nM calculated by 3σ/S. The successful application of the designed method has been promoted to detect Hg2+ in some water samples, displaying a great potential in practical application. Furthermore, the use of a smartphone made our proposed method simple and accurate, and thus puts forward a possible way for in situ and real-time monitoring.

Matrix redox interference-free nanozyme-amplified detection of Hg2+ using thiol-modified phosphatase-mimetic nanoceria

Given heavy metals pose huge threats to ecological system and human health, it is significant to monitor them. With the favorable feature of catalytic signal amplification, redox-type nanozymes have been widely used to detect heavy metals. However, the presence of redox substances in samples can interfere with these catalytic reactions, impacting the accuracy and repeatability of detection. To avoid the situation, here we designed a non-redox nanozyme (3-mercaptopropionic acid modified nanoceria, MPA-CeO2) and developed a novel approach free from matrix redox interference to detect Hg2+. The well-dispersed MPA-CeO2 showed high and stable phosphatase-mimetic activity to catalyze the hydrolysis of colorless p-nitrophenyl phosphate (p-NPP) to yellow p-nitrophenol (p-NP). The addition of Hg2+ could bind specifically onto the MPA-CeO2 particles through S–Hg bond and cause the latter to aggregate, thereby suppressing the ability of MPA-CeO2 with shielded active surfaces to hydrolyze p-NPP. According to the simple principle, highly sensitive and specific colorimetric measurement of Hg2+ was achieved, and excellent reliability and practicability were demonstrated by real sample analysis. To our best knowledge, this study is the first one of detecting Hg2+ using phosphatase-mimicking nanozymes, and it will inspire the exploration of new analytical methods via designing non-redox nanozymes for various targets.

Synthesis of a water-stable CsPbBr3 perovskite for selective detection of mercury ion in water.

By using the method of low-temperature crystallization, CsPbBr3 perovskite nanocrystals (PNCs) coated with trifluoroacetyl lysine (Tfa-Lys) and oleamine (Olam) were synthesized in aqueous solution. The structure of the CsPbBr3 PNCs was characterized by many methods, such as ultraviolet (UV)-visible absorption spectrophotometer, fluorescence spectrophotometer, transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. The fluorescence emission of the CsPbBr3 PNCs is stable in water for about 1 day at room temperature. It was also found that the fluorescence of the PNCs could be obviously and selectively quenched after the addition of mercury ion (Hg2+ ), allowing a visual detection of Hg2+ by the naked eye under UV light illumination. The fluorescence quenching rate (I0 /I) has a good linear relationship with the addition of Hg2+ in the concentration range 0.075 to 1.5 mg/L, with a correlation coefficient (R2 ) of 0.997, and limit of detection of 0.046 mg/L. The fluorescence quenching mechanism of the PNCs was determined by the fluorescence lifetime and X-ray photoelectron spectroscopy (XPS) of the PNCs. Overall, the synthesis method for CsPbBr3 PNCs is simple and rapid, and the as-prepared PNCs are stable in water that could be conveniently used for selective detection of Hg2+ in the water environment.

Selective and Sensitive Detection of Hg2+ and Ag+ by a Fluorescent and Colorimetric Probe with Large Stokes Shift.

Development of fluorescent sensors with large Stokes shift for selective detection of heavy metals is of great importance. A novel fluorescent probe with extremely large Stokes shift (212nm) was synthesized for selective and simultaneous detection of Hg2+ and Ag+ ions. The deep yellow probe turned colorless or pale yellow after addition of Hg2+ or Ag+. The new probe could be utilized for absorption spectral detection of Hg2+ and Ag+ both in ethanol and aqueous solution. Addition of Hg2+ and Ag+ ions caused significant decrease in the fluorescence intensity of the new probe and the selective recognition of Hg2+ and Ag+ was not interfered by common competitive metal ions including Li+, Na+, K+, Cu2+, Fe2+, Zn2+, Co2+, Ni2+, Mn2+, Sr2+, Ca2+, Mg2+, Al3+, Cr3+ and Fe3+. The detection limit for Hg2+ and Ag+ was calculated to be 4.68μM and 4.29μM, respectively. Application of the new probe for quantitative determination of Hg2+ and Ag+ concentrations in real water samples was accomplished.

Development of a Novel H-Shaped Electrochemical Aptasensor for Detection of Hg2+ Based on Graphene Aerogels-Au Nanoparticles Composite.

Hg2+, a highly toxic heavy metal, poses significant environmental and health risks, necessitating rapid detection methods. In this study, we employed an electrochemical aptasensor for rapid and sensitive detection of Hg2+ based on DNA strands (H2 and H3) immobilized graphene aerogels-Au nanoparticles (GAs-AuNPs) hybrid recognition interface and exonuclease III (Exo III)-mediated cyclic amplification. Firstly, Gas-AuNPs were modified on the surface of the ITO electrode to form a sensing interface to increase DNA loading and accelerate electron transfer. Then, DNA helper was generated with the addition of Hg2+ via Exo III-mediated cycling. Finally, the hairpin structures of H2 and H3 were opened with the DNA helper, and then the methylene blue (MB) functionalized DNA (A1 and A2) combined with the H2 and H3 to form an H-shaped structure. The current response of MB as an electrochemical probe was proportional to the concentration of Hg2+. Under optimal conditions, the aptasensor showed excellent performance for Hg2+, achieving a linear range from 1 fM to 10 nM and a detection limit of 0.16 fM. Furthermore, the aptasensor was used to detect Hg2+ in spiked milk samples, achieving a high recovery rate and demonstrating promising application prospects.

Portable smartphone-assisted ratiometric fluorescent test paper based on one-pot synthesized dual emissive carbon dots for visualization and quantification of mercury ions.

Dual-emissive fluorescent carbon dots (CDs) were prepared through the solvothermal method with citric acid and urea as raw materials and dimethylformamide as the solvent. Two emission peaks were observed at 465nm and 630nm. Hg2+ could selectively quench the fluorescence at 630nm, but the fluorescence intensity at 465nm was less affected. Accordingly, a ratiometric fluorescence sensor for Hg2+ detection was developed, with a linear detection range of 0.5-40μM and a limit of detection (LOD) of 37nM. The dual-emissive CDs were loaded on the surface of the filter paper to fabricate Hg2+ detection test paper. The color of the test paper could be changed from pink purple to blue by the addition of Hg2+, and thus the qualitative and quantitative detection of Hg2+ could be realized. The concentration distinguishable by thenaked eye reached 50μM, and the quantitative detection range was 5-10,000μM. This method shows excellent selectivity for Hg2+ and can be used to detect Hg2+ in real water samples, providing a highly potential sensing platform for rapid on-site detection of mercury ions.

Naphthalimide-benzimidazole conjugate towards “Turn-on” recoginition of Hg2+ in pure aqueous medium

A chemosensor, 6-(1-cyclohexyl-1H-benzo[d]imidazol-5-yl)-2-(2-(diethylamino)ethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (9), containing 1H,3H-benzo[de]isochromene-1,3-dione and 1-cyclohexyl-1H-benzo[d]imidazole moieties has been designed and found to be selective towards Hg2+ ions over-tested wide-range of metal ions. Compound 9 shows the absorption and emission peaks at 370 nm and 540 nm, respectively. The addition of Hg2+ ions to compound 9 (20 μM; H2O, pH = 7.4) prompted the formation of a 2:1 ligand–metal complex, 9-Hg2+, which shows a significant blue-shifted emission enhancement to 495 nm, due to the mechanism of ligand to metal charge transfer. The formation of compound 9 and Hg2+ ions complex has also been confirmed through mass spectrometry and 1H NMR titrations. The photophysical properties of the compound and its complex corroborated with Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) calculations.

Smartphone-Enabled Fluorescence and Colorimetric Platform for the On-Site Detection of Hg2+ and Cl- Based on the Au/Cu/Ti3C2 Nanosheets.

Smartphone-assisted fluorescence and colorimetric methods for the on-site detection of Hg2+ and Cl- were established based on the oxidase-like activity of the Au-Hg alloy on the surface of Au/Cu/Ti3C2 NSs. The Au nanoparticles (NPs) were constructed via in-situ growth on the surface of Cu/Ti3C2 NSs and characterized by different characterization techniques. After the addition of Hg2+, the formation of Hg-Au alloys could promote the oxidization of o-phenylenediamine (OPD) to generate a new fluorescence emission peak of 2,3-diaminopenazine (ADP) at 570 nm. Therefore, a turn-on fluorescence method for the detection of Hg2+ was established. As the addition of Cl- can influence the fluorescence of ADP, the fluorescence intensity was constantly quenched to achieve the continuous quantitative detection of Cl-. Therefore, a turn-off fluorescence method for the detection of Cl- was established. This method had good linear ranges for the detection of Hg2+ and Cl- in 8.0-200.0 nM and 5.0-350.0 µM, with a detection limit of 0.8 nM and 27 nM, respectively. Depending on the color change with the detection of Hg2+ and Cl-, a convenient on-site colorimetric method for an analysis of Hg2+ and Cl- was achieved by using digital images combined with smartphones (color recognizers). The digital picture sensor could analyze RGB values in concentrations of Hg2+ or Cl- via a smartphone app. In summary, the proposed Au/Cu/Ti3C2 NSs-based method provided a novel and more comprehensive application for environmental monitoring.

A novel method to prepare water-soluble cellulose-based fluorescent probes for highly sensitive and selective detection and removal of Hg2+/Hg22+ ions

Improving the water solubility of natural product cellulose and using it to treat heavy metal ions is very important. In this work, cellulose-based fluorescent probes containing BODIPY fluorophore were synthesized by simple chemical method, which realized the selective recognition and removal of Hg2+/Hg22+ ions in an aqueous system. Firstly, fluorescent small molecule (BOK-NH2) bearing -NH2 group was synthesized through Knoevenagel condensation reaction between BO-NH2 and cinnamaldehyde. Secondly, via the etherification of -OH on the cellulose, substituents bearing -C ≡ CH groups with different lengths at the end are grafted on the cellulose. Finally, cellulose-based probes (P1, P2, and P3) were prepared by amino-yne click reaction. The solubility of cellulose is improved greatly, especially the cellulose derivative with branched long chains has excellent solubility in water (P3). Benefiting from the improved solubility, P3 could be processed into solutions, films, hydrogels, and powders. Upon the addition of Hg2+/Hg22+ ions, the fluorescence intensity enhanced, which are “turn-on” probes. At the same time, the probes could be utilized as efficient adsorbents for Hg2+/Hg22+ ions. The removal efficiency of P3 for Hg2+/Hg22+ is 79.7 %/82.1 %, and the adsorption capacity is 159.4 mg·g−1/164.2 mg·g−1. These cellulose-based probes are expected to be employed in the treatment of polluted environments.

Rationally designed novel phenazine based chemosensor with real time Hg2+ sensing application

Phenazine derivatives have been explored in the selective detection of ions due to their binding ability with analytes. In this context, C-6 sulfenylated benzo[a]phenazine-5-ols (3a-d)have been synthesied and explored in sensing application. Initially, the molecules were designed by utilizing benzo[a]phenazin-5-ol as a core structure variably substituted with electronically diverse aryl thiols to investigate the substituent effect on their electrostatic properties. The ground state geometry of all the designed molecules was optimized with DFT using B3LYP/6-311G+(d,p) level of theory. Energy gap between FMOs was observed to be minimum and maximum for electron rich and deficient frameworks, respectively. The LUMO electron density in all the designed molecules except for compound bearing nitro group (3c) lies on the phenazine unit. This exceptional behavior enthusiased us to explore their photophysical properties. The compounds were synthesized and characterized using FT-IR, NMR and mass spectrometric techniques. In an attempt to examine their spectral behavior in different solvents, their absorption and emission spectra were recorded. The compounds exhibited absorptions maxima ranging between 475-514 nm, which shifted to longer wavelength while changing solvent polarity from CHCl3 to DMSO thus depicting positive solvatochromism. Similarly, the emission maxima was observed in a range of 570–685 nm with a maximum stokes shift of 6454 cm−1 for 3c. The compound 3c was further explored in the sensing application using DMSO:Water (60:40, v/v) mixture. A blue shift of 30 nm with nearly 7 fold increase in the emission intensity was observed upon addition of Hg2+ into 3c solution. Moreover, LOD of 21.9 nM and binding stoichiometry of 2:1 as determined by Benesi–Hildebrand and Job's plot establish the robust response of developed probe towards Hg2+ ion. The mechanism of complex formation was predicted by 1H NMR titration and DFT studies. Finally, the developed probe has been successfully utilized for sensing Hg2+ in real water samples.

Efficient removal and rapid detection of Hg2+ in environment by multifunctional binding strategy on polystyrene microspheres

Nowadays, developing a multifunctional platform with the ability to detect and remove heavy metal ions remains a huge challenge in the field of environmental pollution control. Herein, L-cysteine functionalized novel polystyrene microspheres with special fluorescent scattering effect are constructed by simple one-step reaction. This multifunctional platform is very attractive in terms of mercury ion removal and detection. To achieve the purpose of removal, polystyrene-L-cysteine (PS-LCYS) have a lot of active sites (-SH/-NH2/-OH), which can coordinate with Hg2+ to form new complexes (PS-LCYS-Hg2+). Interestingly, fluorescent scattering was enhanced with the addition of Hg2+, indicating PS-LCYS can be used to detect Hg2+. As expected, this strategy achieved a low detection limit of 85 nM in a wide range of 50–1700 μM. At the same time, target-induced aggregation rendered the effective embedding and encapsulation of Hg2+ by PS-LCYS, showing good absorption of 92.69–94.32% within 10 min. And the maximum Hg2+ absorption capacity of PS-LCYS was estimated to be 1314 mg/g. What’s more, this platform can be regenerated and reused with the treatment of EDTA, achieving 88.54% removal rate after 7 circulations. This multifunctional platform not only realized high sensitivity detection, but also can absorb a large number of mercury ions in the water environment in a short time. After repeated use, PS-LCYS still maintained good detection and adsorption performance. Therefore, the platform had the potential to solve the problem of heavy metal ion pollution.

Triazine based fluorescent sensor for sequential detection of Hg2+ and L-Cysteine in real samples and application in logic Gate: A combination of Extensive experimental and theoretical analysis

Triazine based fluorescent sensor TBT was rationally designed and synthesized to achieve sequential detection of Hg2+ and L-cysteine based on the presence of sulfur moiety and suitable cavity in the molecule. Sensor TBT exhibited excellent sensing potential for the selective detection of Hg2+ ions and L-cysteine (Cys) in real samples. Upon addition of Hg2+ to sensor TBT, enhancement in emission intensity of sensor TBT was observed which was accredited to the presence of sulfur moiety and size of cavity in the sensor. Upon interaction with Hg2+ blockage of intramolecular charge transfer (ICT) along with chelation-enhanced fluorescence (CHEF) resulted in the increase in fluorescence emission intensity of sensor TBT. Further, TBT-Hg2+ complex was employed for the selective detection of Cys through fluorescence quenching mechanism. This was attributed to the significantly stronger interaction of Cys with Hg2+, which resulted in the formation of Cys-Hg2+ complex and subsequently sensor TBT was released from TBT-Hg2+ complex. The nature of interaction between TBT-Hg2+ and Cys-Hg2+ complex was evaluated through 1H NMR titration experimentations. Extensive DFT studies were also carried out which include thermodynamic stability, frontier molecular orbitals (FMO), density of states (DOS), non-covalent interaction (NCI), quantum theory of atom in molecule (QTAIM), electron density differences (EDD) and natural bond orbital (NBO) analyses. All the studies supported the non-covalent type of interaction between analytes and sensor TBT. The limit of detection for Hg2+ ions was found to be as low as 61.9 nM. Sensor TBT was also employed for the quantitative detection of Hg2+ and Cys in real samples. Additionally, logic gate was fabricated by using sequential detection strategy.

Fe/S Redox-Coupled Mercury Transformation Mediated by Acidithiobacillus ferrooxidans ATCC 23270 under Aerobic and/or Anaerobic Conditions.

Bioleaching processes or microbially mediated iron/sulfur redox processes in acid mine drainage (AMD) result in mineral dissolution and transformation, the release of mercury and other heavy metal ions, and changes in the occurrence forms and concentration of mercury. However, pertinent studies on these processes are scarce. Therefore, in this work, the Fe/S redox-coupled mercury transformation mediated by Acidithiobacillus ferrooxidans ATCC 23270 under aerobic and/or anaerobic conditions was studied by combining analyses of solution behavior (pH, redox potential, and Fe/S/Hg ion concentrations), the surface morphology and elemental composition of the solid substrate residue, the Fe/S/Hg speciation transformation, and bacterial transcriptomics. It was found that: (1) the presence of Hg2+ significantly inhibited the apparent iron/sulfur redox process; (2) the addition of Hg2+ caused a significant change in the composition of bacterial surface compounds and elements such as C, N, S, and Fe; (3) Hg mainly occurred in the form of Hg0, HgS, and HgSO4 in the solid substrate residues; and (4) the expression of mercury-resistant genes was higher in earlier stages of growth than in the later stages of growth. The results indicate that the addition of Hg2+ significantly affected the iron/sulfur redox process mediated by A. ferrooxidans ATCC 23270 under aerobic, anaerobic, and coupled aerobic-anaerobic conditions, which further promoted Hg transformation. This work is of great significance for the treatment and remediation of mercury pollution in heavy metal-polluted areas.

Development of low-cost copper nanoclusters for highly selective “turn-on” sensing of Hg2+ ions

The development of low-cost earth abundant metal based fluorescent sensors for a rapid and selective nanomolar level detection of Hg2+ is essential due to the increasing world-wide concern of its detrimental effect on humans as well as the environment. Herein, we present a perylene tetracarboxylic acid functionalized copper nanoclusters (CuNCs) based “turn-on” fluorescence probe for highly selective detection of toxic Hg2+ ions. The fabricated CuNCs exhibited high photostability with emission maximum centered at 532 nm (λex = 480 nm). The fluorescence intensity of CuNCs was remarkably enhanced upon the addition of Hg2+ over other competing ions and neutral analytes. Notably, the ‘turn-on’ fluorescence response exhibits highly sensitive detection limit as low as 15.9 nM (S/N ∼ 3). The time resolved fluorescence spectroscopy suggested the energy transfer between CuNCs and Hg2+ ions following either inhibited fluorescence resonance energy transfer (FRET) or surface modification of CuNCs during Hg2+ sensing. This study offers the systematic design and development of new fluorescent ‘turn-on’ nanoprobes for rapid and selective recognition of heavy metal ions.

Metal ion responsive bifunctional bis(indolyl)methane derivative: Excitation-triggered alteration in the sensing behavior

Bisindolyl based chromogenic probe with a bispicolyl binding site has been designed, that can form nanoscopic aggregates in water medium. The compound showed selective chromogenic response towards Cu2+ and Hg2+, solution color changes from red to light brown immediately as a result. Interestingly, we can specifically excite either monomer or aggregate species by choosing a suitable excitation channel. The compound showed turn-off response selectively upon addition of Hg2+ when excite at monomer excitation channel (λex = 390 nm). On the contrary, fluorescence quenching was observed with both Cu2+ and Hg2+ ions when excited through the aggregate channel (λex = 470 nm). Not only selectivity, but the sensitivity of the compound towards target metal ions depends on the excitation wavelength. Further, the detection of metal ions, such as Cu2+ and Hg2+ is performed in the biological matrices, such as diluted blood serum and plasma samples, etc. Finally, bioimaging of Hg2+ is achieved both in bacterial (E. Coli) and mammalian (HEK293T) cells.

One-Pot Synthesis of Dual-Emissive Carbon Dots for Ratiometric Fluorescent Determination of Hg2.

Mercury ion is a global toxic and hazardous environmental pollutant. In this work, a facile and selective ratiometric fluorescent probe was constructed for the detection of mercury ion. The dual-emissive carbon dots (BYCDs) were fabricated by a one-pot hydrothermal method utilizing o-phenylenediamine and glycine as raw materials, and the prepared BYCDs had two independent fluorescence emission peaks at 426nm and 543nm under a single excitation wavelength. Based on the change of the intensity ratio of the two fluorescence emission peaks after the addition of Hg2+, a sensitive and selective ratiometric fluorescent probe based on BYCDs was constructed for the detection of Hg2+ with good linearity ranging from 0.95-50μM and a detection limit of 0.27μM. In addition, the recovery of this probe was satisfactory in the standard addition experiments of real water samples, and it could be applied to the analysis of Hg2+ in real water samples.

Ratio fluorescence sensor based on CD/Cu-MOFs for detection of Hg2.

Trace detection of toxic heavy metals is a very important and difficult problem in several areas: convenience, sensitivity, and reliability. Herein, we develop an innovative fluorescence resonance energy transfer (FRET)-based ratio fluorescence sensor for the detection of heavy metal mercury ion (H g 2+). The sensing platform is composed of coumarin derivatives (CDs) and a copper metal-organic framework (Cu-MOF) named CD/Cu-MOF. The constructed CD/Cu-MOFs ratio fluorescence sensor exhibits dual emission peaks at 430 and 505nm under the single excitation wavelength of 330nm. With the addition of H g 2+, the fluorescence intensity of the system at 430nm gradually increased, and the fluorescence intensity at 505nm remained stable, resulting in a change in the fluorescence ratio. There is a good logarithmic relationship between the H g 2+ concentration in the range from 2×10-8 to 0.001nM and the ratio of the fluorescence emission intensity of the system (F 430/F 505) (R 2=0.9901), and its calculated detection limit is 3.76×10-9 n M. In addition, the CD/Cu-MOFs ratio fluorescence sensor has achieved a good recovery rate of standard addition in the actual food sample recovery experiment, which provides an effective method for the detection of H g 2+ in food samples.