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1.
A simple and sensitive DNA‐stablized gold nanoparticle (AuNP)‐based chemiluminescent (CL) probe for detecting mercury ion (Hg2+) in aqueous solution has been developed. The CL strategy relies upon the catalytic activity of unmodified AuNPs on the luminol–H2O2 CL reaction, and the interaction of unmodified AuNPs with DNA. The unmodified AuNPs can effectively differentiate unstructured and folded DNA. The DNA desorbs from AuNPs in the presence of Hg2+, leading to the increase in CL signal. By rationally varying the number of thymine in single‐strand oligonucleotides, the detection range could be tuned. Employing single‐strand oligonucleotides with 14 thymine in the detecting system, a sensitive linear range for Hg2+ ions from 5.0 × 10–10 to 1.0 × 10–7 mol/L and a detection limit of 2.1 × 10–10 mol/L are obtained. Changing the number of thymine to 10 and 6, it leads to a narrow detection range but a high sensitivity. Besides, DNA‐based CL nanoprobes exhibit a remarkable selectivity for Hg2+ ions over a variety of competing metal ions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

2.
《Inorganica chimica acta》1988,146(2):233-241
Dimethylsulfoxide and aqueous solutions of mercury(II) in large excess over iodide have been investigated by X-ray scattering techniques supported by Raman spectroscopic measurements. The composition of the solutions has been selected to ensure that the cationic complex Hg2I3+ is the predominant iodide species. The structure parameters of the solvated Hg2I3+ ion have been refined by a least- squares procedure on the scattering data, using known structural parameters for the additional molecular entities present. The Hg2I3+ entity is more or less identical in DMSO and water. The HgI bond distance is 2.613(12) and 2.632(5) Å and the HgHg distance is 3.66(5) and 3.70(1) Å in DMSO and water, respectively. This yields a HgIHg angle of 89° in both solvents. The mercury(II) atom in this complex is most probably solvated in a tetrahedral fashion by three DMSO or H2O molecules. The structure of Hg2I3+ is discussed in the light of recent results for the Ag4I3+ complex in solution and relevant crystal structures.  相似文献   

3.
The behaviors of 15 kinds of metal ions in the thiol‐capped CdTe quantum dots (QDs)–H2O2 chemiluminescence (CL) reaction were investigated in detail. The results showed that Ag+, Cu2+ and Hg2+ could inhibit CdTe QDs and H2O2 CL reaction. A novel CL method for the selective determination of Ag+, Cu2+ and Hg2+ was developed, based on their inhibition of the reaction of CdTe QDs and H2O2. Under the optimal conditions, good linear relationships were realized between the CL intensity and the logarithm of concentrations of Ag+, Cu2+ and Hg2+. The linear ranges were from 2.0 × 10?6 to 5.0 × 10?8 mol L?1 for Ag+, from 5.0 × 10?6 to 7.0 × 10?8 mol L?1 for Cu2+ and from 2.0 × 10?5 to 1.0 × 10?7 mol L?1 for Hg2+, respectively. The limits of detection (S/N = 3) were 3.0 × 10?8, 4.0 × 10?8 and 6.7 × 10?8 mol L?1 for Ag+, Cu2+ and Hg2+, respectively. A possible mechanism for the inhibition of CdTe QDs and H2O2 CL reaction was also discussed. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

4.
Currently, the fluorescent probe is an important method for detecting heavy metal ions, especially mercury ion (Hg2+), which is harmful to the health of humans and the environment due to its toxicity and extensive use. In this paper, we designed and synthesized a colorimetric and long‐wavelength fluorescent probe Hg‐P with high sensitivity and excellent selectivity, which could detect Hg2+ by the changes of visual color, fluorescence and absorption spectroscopy. With the addition of Hg2+ to probe Hg‐P solution, its color changed from yellow to pink, and showed a 171 nm red‐shifted absorption spectrum. Probe Hg‐P was used in real water and soil solution samples to detect Hg2+, and the result is satisfactory. Therefore, this new probe shows great value and application in detecting Hg2+ in the environment.  相似文献   

5.
The as‐prepared graphene oxide (GO) exhibited a strong catalytic effect on reduction of HAuCl4 by trisodium citrate to form gold nanoplasmons (AuNPs) with a strong surface‐enhanced Raman scattering (SERS) effect at 1615 cm?1 in the presence of molecular probe Victoria blue 4R (VB4r). SERS intensity increased with nanocatalyst GO concentration due to the formation of more AuNP substrates. The aptamer (Apt) of Hg2+ can bind to GO to form Apt–GO complexes, which can strongly inhibit nanocatalysis. When target Hg2+ is present, the formed stable Hg2+–Apt complexes are separated from the GO surface, which leads to GO catalysis recovery. The enhanced SERS signal was linear to Hg2+ concentration in the range 0.25–10 nmol/L, with a detection limit of 0.08 nmol/L Hg2+. Thus, a new gold nanoplasmon molecular spectral analysis platform was established for detecting Hg2+, based on Apt regulation of GO nanocatalysis.  相似文献   

6.
In this study, we demonstrated a highly sensitive, selective, and reversible chemosensor for Hg2+ determination. This chemosensor was synthesized by direct condensation of thymin‐1‐ylacetic acid with zinc tetraaminoporphyrin, which has a porphyrin core as the fluorophore and four thymine (T) moieties as the specific interaction sites for Hg2+. The probe (4T‐ZnP) exhibited split Soret bands with a small peak at 408 nm and a strong band at 429 nm in a dimethylformamide/H2O (7/3, v/v) mixed solvent as well as a strong emission band at 614 nm. Upon the addition of Hg2+, the probe displayed strong fluorescence quenching due to the formation of T‐Hg2+‐T complexes. With the aid of the fluorescence spectrometer, the chemosensor in the dimethylformamide/H2O (7/3, v/v) mixed solvent (0.3 μM) exhibited a detection limit of 6.7 nM. Interferences from other common cations, such as Co2+, K+, Sn2+, Zn2+, Cu2+, Ni2+, Mn2+, Na+, Ca2+, Mg2+, Pb2+, and Cd2+, associated with Hg2+ analysis were effectively inhibited. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

7.
A simple one‐step thermal treatment to prepare strong fluorescent sulfur and nitrogen co‐doped graphene quantum dots (SN‐GQD) using citric acid and l ‐cysteine as precursors was developed. The ultra‐weak chemiluminescence (CL) from the reaction of hydrogen peroxide (H2O2) and periodate (IO4?) was significantly enhanced by SN‐GQD in acidic medium. The enhanced CL was induced by excited‐state SN‐GQD (SN‐GQD*), which was produced from the transfer energy of (O2)2* and 1O2 to SN‐GQD and recombination of oxidant‐injected holes and electrons in SN‐GQD. In the presence of tryptophan (Trp), the CL intensity of the SN‐GQD–H2O2–KIO4 system was greatly diminished. This finding was used to design a novel method for determination of Trp in the linear range 0.6–20.0 μM, with a limit of detection (LOD) of 58.0 nM. Furthermore, Hg2+ was detectable in the range 0.1–9.0 μM with a LOD of 64.0 nM, based on its marked enhancement of the SN‐GQD–H2O2–KIO4 CL system. The proposed method was successfully applied to detect Trp in milk and human plasma samples and Hg2+ in drinking water samples, with recoveries in the range 95.7–107.0%.  相似文献   

8.
Novel phenanthroline Schiff base fluorescent sensors L1 , L2 , and D1 were designed and synthesized. The sensing abilities of the compounds in the presence of metal cations (Li+, Na+, K+, Ag+, Mg2+, Ba2+, Ca2+, Mn2+, Pb2+, Hg2+, Ni2+, Zn2+, Cd2+, Co2+, Cu2+, Cr3+, Fe3+, Fe2+, Al3+, and Eu3+) were studied by UV‐vis and fluorescent spectroscopy. The compounds L1 , L2 , and D1 could act as Eu3+ ion turn‐off fluorescent sensors based on ligand‐to‐metal binding mechanism in DMSO‐H2O solution (v/v = 1:1, 10 mM Tris, pH = 7.4). Additionally, the L1 –Eu3+ and D1 –Eu3+ complexes could be applied as turn‐on enantioselective sensors sensing of malate anion isomers with color changes. Furthermore, biological experiments using living PC‐12 cells demonstrated that L1 and D1 had excellent membrane permeability and could be used as effective fluorescent sensors for detecting Eu3+ and malate anion in living cells.  相似文献   

9.
A quinolinocyclodextrin, that is, MQAS-β-cyclodextrin (MQAS = N-(2-methyl-8-amino- quinolyl)-p-aminobenzene sulfonamide) was synthesized. Further experiments showed that it could form very stable stoichiometric 2:1 complex with Zn2+ in water. Significantly, the resultant quinolinocyclodextrin/Zn2+ complex showed the specific fluorescence response to Hg2+ over other metal ions, which could be readily distinguished in either aqueous solution or the PVA-based thin film. This finding would enable Zn·32 complex as a convenient and highly efficient fluorescence sensor for the detection of Hg2+.  相似文献   

10.
In this paper, an innovative and facile one‐pot method for synthesizing water‐soluble and stable fluorescent Cu nanoclusters (CuNCs), in which glutathione (GSH) served as protecting ligand and ascorbic acid (AA) as reducing agent was reported. The resultant CuNCs emitted blue‐green fluorescence at 440 nm, with a quantum yield (QD) of about 3.08%. In addition, the prepared CuNCs exhibited excellent properties such as good water solubility, photostability and high stability toward high ionic strength. On the basis of the selective quenching of Hg2+ on CuNCs fluorescence, which may be the result of Hg2+ ion‐induced aggregation of the CuNCs, the CuNCs was used for the selective and sensitive determination of Hg2+ in aqueous solution. The proposed analytical strategy permitted detection of Hg2+ in a linear range of 4 × 10?8 to 6 × 10?5 M, with a detection limit of 2.2 × 10?8 M. Eventually, the practicability of this sensing approach was confirmed by its successful application to assay Hg2+ in tap water, Lotus lake water and river water samples with the quantitative spike recoveries ranging from 96.9% to 105.4%.  相似文献   

11.
An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA–AuNPs@Tb–AMP (BSA, bovine serum albumin; AMP, adenosine 5′‐monophosphate; AuNPs, Au nanoparticles) metal–organic framework (MOF) nanostructures were synthesized by encapsulating BSA–AuNPs into Tb–AMP MOFs for the detection of 2,6‐pyridinedicarboxylic acid (DPA) and Hg2+. DPA could strongly co‐ordinate with Tb3+ to replace water molecules from the Tb3+ center and accordingly enhanced the fluorescence of Tb–AMP MOFs. The fluorescence of BSA–AuNPs at 405 nm remained constant. While the fluorescence of BSA–AuNPs at 635 nm was quenched after Hg2+ was added, the fluorescence of Tb–AMP MOFs remained constant. Accordingly, a ratiometric fluorescence nanosensor was constructed for detection of DPA and Hg2+. The ratiometric nanosensor exhibited good selectivity to DPA over other substances. The F545/F405 linearly increased with increase of DPA concentration in the range of 50 nM to 10 μM with a detection limit as low as 17.4 nM. F635/F405 increased linearly with increase of Hg2+ concentration ranging from 50 nM to 1 μM with a detection limit as low as 20.9 nM. Additionally, the nanosensor could be successfully applied for the determination of DPA and Hg2+ in running water.  相似文献   

12.
Peptide-based hydrogels are attractive biological materials. Study of their self-assembly pathways from their monomer structures is important not only for undertaking the rational design of peptide-based materials, but also for understanding their biological functions and the mechanism of many human diseases relative to protein aggregation. In this work, we have monitored the conformation, morphological, and mechanical properties of a hydrogel-forming peptide during hydrogelation in different dimethylsulfoxide (DMSO)/H2O solutions. The peptide shows nanofiber morphologies in DMSO/H2O solution with a ratio lower than 4:1. Increased water percentage in the solution enhanced the hydrogelation rate and gel strength. One-dimensional and two-dimensional proton NMR and electron microscopy studies performed on the peptide in DMSO/H2O solution with different ratios indicate that the peptide monomer tends to adopt a more helical structure during the hydrogelation as the DMSO/H2O ratio is reduced. Interestingly, at the same DMSO/H2O ratio, adding Ca2+ not only promotes peptide hydrogelation and gel strength, but also leads to special shear-thinning and recovery properties of the hydrogel. Without changing the peptide conformation, Ca2+ binds to the charged Asp residues and induces the change of interfiber interactions that play an important role in hydrogel properties.  相似文献   

13.
Herring sperm DNA (hsDNA) was used to modify 10 nm nanogold to obtain a resonance scattering (RS) probe (AuhsDNA) for detection of Hg2+. In the presence of salt, Hg2+ interacts with AuhsDNA to form stable Hg2+–hsDNA complexes, and releases nanogold particles to form larger nanogold clusters that can be removed by membrane filtration. The excess AuhsDNA in the filtrate solution exhibits a catalytic effect on the reaction between hydroxylamine (NH2OH) and Cu(II). The excess AuhsDNA decreased with the addition of Hg2+, which led the RS intensity at 602 nm to decrease. The decreased RS intensity (Δl602 nm) had a linear response to Hg2+ concentration in the range of 0.4–400 nM, with a detection limit of 0.2 nM Hg2+. This RS method was applied for the detection of Hg2+ in water samples, with sensitivity, selectivity and simplicity. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

14.
Exposure to even very low concentrations of Pb2+ is known to cause cardiovascular, neurological, developmental, and reproductive disorders, and affects children in particular more severely. Consequently, much effort has been dedicated to the development of colorimetric and fluorescent sensors that can selectively detect Pb2+ ions. Here, we describe the development of a triazole‐based fluorescent sensor L5 for Pb2+ ion detection. The fluorescence intensity of chemosensor L5 was selectively quenched by Pb2+ ions and a clear color change from colorless to yellow could be observed by the naked eye. Chemosensor L5 exhibited high sensitivity and selectivity towards Pb2+ ions in phosphate‐buffered solution [20 mM, 1:9 DMSO/H2O (v/v), pH 8.0] with a 1:1 binding stoichiometry, a detection limit of 1.9 nM and a 6.76 × 106 M?1 binding constant. Additionally, low‐cost and easy‐to‐prepare test strips impregnated with chemosensor L5 were also produced for efficient of Pb2+ detection and proved the practical use of this test.  相似文献   

15.
A series of six 3,6-bis(imidazolium-3-yl)pyridazine derivatives with different imidazole-N substituents have been synthesized and isolated as the salts [H2L]Cl2 (1a)-(6a) and [H2L](PF6)2 (1b)-(6b). Solid state structures have been determined crystallographically for eleven out of the twelve compounds, revealing diverse hydrogen bonding patterns that involve the imidazolium-C2H units and the anions. N-heterocyclic carbene (NHC) mercury(II) complexes [Hg2L2](PF6)4 (7)-(9) are readily formed in good yields from ligand precursors [H2L](PF6)2 and Hg(OAc)2, as long as imidazole-N substituents are not too bulky. X-ray crystallography reveals double helical bimetallic arrangements for the stable [Hg2L2]4+ cations. Ligand scrambling in [Hg2L2]4+ occurs only in the presence of free carbene precursor, presumably via an associative mechanism.  相似文献   

16.
The 2,4,5-tris(2-pyridyl)imidazole ( L ) molecule has been evaluated as a probe for dual sensing of Hg2+ and Cu2+ ions in EtOH/HEPES buffer medium (5 mM, pH = 7.34, 1:1, v/v). Probe L shows a good sensitive and selective turn-off response in the presence of both Hg2+ and Cu2+ ions, which is comprehensible under long UV light. The probe can detect Cu2+ ion in the pH range 3–11 and Hg2+ ion in pH 6–8. The limit of detection for Cu2+ (0.77 μM) is well under the allowable limit prescribed by the United States Environmental Protection Agency. Two metal (Cu2+/Hg2+) ions are needed per L for complete fluorescence quenching. The probe shows marked reversibility on treatment with Na2EDTA, making the protocol more economical for practical purposes. Paper strip coated with the L solution of EtOH can detect the presence of Cu2+ and Hg2+ ions in the sample using visible quenching of the fluorescence intensity. Density functional theory–time-dependent density functional theory (DFT–TDDFT) calculations support experimental observations, and d-orbitals of Cu2+/Hg2+ provide a nonradiative decay pathway. Cell imaging study using HDF and MDA-MB-231 cells also supported the viability of L in detecting Cu2+ and Hg2+ ions in living cells.  相似文献   

17.
We report the fabrication of a novel easily available turn‐on fluorescent water‐soluble polymeric chemosensor for Hg2+ ions that was simply prepared by micellar free radical polymerization of a water‐insoluble organic rhodamine‐based Hg2+‐recognizing monomer (GR6GH), with hydrophilic monomers acrylamide (AM) and acrylic acid (AA). The chemical structure of the polymeric sensor was characterized by FT‐IR and 1H NMR spectroscopy. The apparent viscosity average molecular weight Mη of poly(acrylamide–acrylic acid) [poly(AM–NaAA)] and the water‐soluble polymeric chemosensor poly(AM–NaAA–GR6GH) were 1.76 × 106 and 6.84 × 104 g/mol, respectively. Because of its amphiphilic property, the water‐soluble polymeric chemosensor can be used as a chemosensor in aqueous media. Upon addition of Hg2+ ions to an aqueous solution of poly(AM–NaAA–GR6GH), fluorescence enhancements were observed instantly. Moreover, other metal ions did not induce obvious changes to the fluorescence spectra. This approach may provide an easily measurable and inherently sensitive method for Hg2+ ion detection in environmental and biological applications. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
A novel multifunctional fluorescent peptide sensor based on pentapeptide dansyl‐Gly‐His‐Gly‐Gly‐Trp‐COOH (D‐P5) was designed and synthesized efficiently using Fmoc solid‐phase peptide synthesis (SPPS). This fluorescent peptide sensor shows selective and sensitive responses to Hg2+ and Cu2+ among 17 metal ions and six anions studied in N‐2‐hydroxyethylpiperazine‐N‐2‐ethane sulfonic acid (HEPES) buffer solution. The peptide probe differentiates Hg2+ and Cu2+ ions by a ‘turn‐on’ response to Hg2+ and a ‘turn‐off’ response to Cu2+. Upon addition of Hg2+ or Cu2+ ions, the sensor displayed an apparent color change that was visible under an ultraviolet lamp to the naked eye. The limits of detection (LOD) of DP‐5 were 25.0 nM for Hg2+ and 85.0 nM for Cu2+; the detection limits for Cu2+ were much lower than the drinking water maximum contaminant levels set out by the United States Environmental Protection Agency (USEPA). It is noteworthy that both D‐P5‐Hg and D‐P5‐Cu systems were also used to detect S2? successfully based on the formation of ternary complexes. The LODs of D‐P5‐Hg and D‐P5‐Cu systems for S2? were 217.0 nM and 380.0 nM, respectively. Furthermore, the binding stoichiometry, binding affinity and pH sensitivity of the probe for Hg2+ and Cu2+ were investigated. This study gives new possibilities for using a short fluorescent peptide sensor for multifunctional detection, especially for anions.  相似文献   

19.
A novel styrylcyanine‐based fluorescent probe 1 was designed and synthesized via facile methods. Ferric ions quenched the fluorescence of probe 1, whereas the addition of ferrous ions led to only small changes in the fluorescence signal. When hydrogen peroxide was introduced into the solution containing probe 1 and Fe2+, Fe2+ was oxidized to Fe3+, resulting in the quenching of the fluorescence. The probe 1/Fe2+ solution fluorescence could also be quenched by H2O2 released from glucose oxidation by glucose oxidase (GOD), which means that probe 1/Fe2+ platform could be used to detect glucose. Probe 1 is fluorescent in basic and neutral media but almost non‐fluorescent in strong acidic environments. Such behaviour enables it to work as a fluorescent pH sensor in both the solution and solid states and as a chemosensor for detecting volatile organic compounds with high acidity and basicity. Subsequently, the fluorescence microscopic images of probe 1 in live cells and in zebrafish were achieved successfully, suggesting that the probe has good cell membrane permeability and a potential application for imaging in living cells and living organisms. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

20.
Spiropyran (SP) and its derivatives operate between their ring opening and closing forms as a versatile molecular platform for the fluorescence detection of cations and anions, using a colour change for signalling. A functionalized SP fluorescence probe, L , was prepared and characterized. Probe L can detect Ca2+ with a fluorescence ‘turn‐on’ response in ethanol solution. It selectively binds Ca2+ to form a 1:1 ligand/metal complex, which produced a new emission band centred at 604 nm. The sensing result was clearly observed by the solution colour change from colourless to pink under visible light, and from blue to red under ultraviolet light. The detection limit was calculated to be 4.53 × 10?8 M for Ca2+. The probe provides another possibility that SP‐based derivatives could be used for the development and detection of metal ions in environmental and physiological systems.  相似文献   

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