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1.
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   

2.
A novel ratiometric fluorescence nanosensor for superoxide anion (O2??) detection was designed with gold nanoparticles‐bovine serum albumin (AuNPs‐BSA)@terbium/guanosine monophosphate disodium (Tb/GMP) nanoscale coordination polymers (NCPs) (AuNPs‐BSA@Tb/GMP NCPs). The abundant hydroxyl and amino groups of AuNPs‐BSA acted as binding points for the self‐assembly of Tb3+ and GMP to form core‐shell AuNPs‐BSA@Tb/GMP NCP nanosensors. The obtained probe exhibited the characteristic fluorescence emission of both AuNPs‐BSA and Tb/GMP NCPs. The AuNPs‐BSA not only acted as a template to accelerate the growth of Tb/GMP NCPs, but also could be used as the reference fluorescence for the detection of O2??. The resulting AuNPs‐BSA@Tb/GMP NCP ratiometric fluorescence nanosensor for the detection of O2?? demonstrated high sensitivity and selectivity with a wide linear response range (14 nM–10 μM) and a low detection limit (4.7 nM).  相似文献   

3.
Two complexes of Tb3+, Gd3+/Tb3+ and one heteronuclear crystal Gd3+/Tb3+ with phenoxyacetic acid (HPOA) and 2,4,6‐tris‐(2‐pyridyl)‐s–triazine (TPTZ) have been synthesized. Elemental analysis, rare earth coordination titration, inductively coupled plasma atomic emission spectrometry (ICP‐AES) and thermogravimetric analysis‐differential scanning calorimetry (TG‐DSC) analysis show that the two complexes are Tb2(POA)6(TPTZ)2·6H2O and TbGd(POA)6(TPTZ)2·6H2O, respectively. The crystal structure of TbGd(POA)6(TPTZ)2·2CH3OH was determined using single‐crystal X‐ray diffraction. The monocrystal belongs to the triclinic system with the P‐1 space group. In particular, each metal ion is coordinately bonded to three nitrogen atoms of one TPTZ and seven oxygen atoms of three phenoxyacetic ions. Furthermore, there exist two coordinate forms between C6H5OCH2COO and the metal ions in the crystal. One is a chelating bidentate, the other is chelating and bridge coordinating. Fluorescence determination shows that the two complexes possess strong fluorescence emissions. Furthermore, the fluorescence intensity of the Gd3+/Tb3+ complex is much stronger than that of the undoped complex, which may result from a decrease in the concentration quench of Tb3+ ions, and intramolecular energy transfer from the ligands coordinated with Gd3+ ions to Tb3+ ions. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

4.
A novel ternary complex, Tb2L4·L′·(ClO4)6·8H2O, has been synthesized using bis(benzylsulfinyl)methane as the first ligand L and 2,2′‐dipyridyl as the second ligand L′. The ternary complex was characterized by element analysis, molar conductivity, coordination titration analysis, infrared, thermogravimetric‐differential scanning calorimetric and ultraviolet spectra. The results indicated that the composition of the complex was Tb2L4·L′·(ClO4)6·8H2O (L = C6H5CH2SOCH2SOCH2C6H5; L′ = Dipy). Fourier transform infrared results revealed that the perchlorate group was bonded with the Tb(III) ion by the oxygen atom, and the coordination was bidentate. The fluorescent spectra illustrated that the complex displayed characteristic fluorescence in the solid state. After the introduction of the second ligand, 2,2‐dipyridyl, the relative emission intensity and fluorescence lifetime of the ternary complex Tb2L4·L′·(ClO4)6·8H2O were enhanced compared to the binary complex TbL2.5(ClO4)3·3H2O. This indicated that the presence of both organic ligand bis(benzylsulfinyl)methane and the second ligand 2,2‐dipyridyl could sensitize the fluorescence intensity of Tb(III) ion, and introduction of the 2,2‐dipyridyl group resulted in an enhancement of the fluorescence of the Tb(III) ternary rare earth complex. The strongest characteristic fluorescence emission intensity of the ternary complex was 9.36 times that of the binary complex. The phosphorescence spectra and fluorescence lifetime of the complex were also measured. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

5.
d ‐penicillamine‐capped cadmium telluride quantum dots (DPA‐capped CdTe QDs) were synthesized as the new fluorescent semiconductor nanocrystal in aqueous solution. Fourier transmission infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, ultraviolet‐visible and photoluminescence spectroscopy were used for characterization of the QDs. Based on the quenching effect of Cu2+ ions on the fluorescence intensity of DPA‐capped CdTe QDs, a new fluorometric sensor for copper(II) detection was developed that showed good linearity over the concentration range 5 × 10–9–3 × 10–6 m with the detection limit 0.4 × 10–9 m . Owing to the strong affinity of the DPA to copper(II), the sensor showed appropriate selectivity for copper(II) compared with conventional QDs. The DPA‐capped CdTe QDs was successfully applied for determination of Cu2+ concentration in river, well and tap waters with satisfactory results. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

6.
A fluorescent probe was developed and characterized, it consisted of terbium(III) with 3‐ally‐salicylohydrazide in ethanol, in which the 1:2 [Tb3+:S1] molar ratio was the best stoichiometric ratio for the probe. The ligand 3‐ally‐salicylohydrazide (S1) was synthesized, then was confirmed by IR, CHN, LC–MS and 1H NMR. The sensitivity of the probe's fluorescence spectra towards the presence of eight organophosphorus pesticides in ethanolic solution was studied, in which the probe showed marked sensitivity towards dichlorvos pesticide. A tangible enhancement of the probe's fluorescence intensity was observed as a consequence of the gradual addition of dichlorvos pesticide. The calculated limit of detection (LOD) was 1.183 μM and limit of quantitation (LOQ) was 3.94 μM. Further characterization of the nature of forces acting in the interaction of the probe with dichlorvos was performed by calculation of binding constants at different temperatures according to the Benesi ? Hildebrand equation, and the thermodynamic parameters ΔH, ΔS and ΔG. In order to assess the analytical applicability of the method, the influence of various potentially interfering anion and cations that naturally occur in water and soil were calculated.  相似文献   

7.
A simple spectrofluorimetric method is described for the determination of DNA, based on its enhancement of the fluorescence intensity of prulifloxacin (PUFX)–Tb3+. The luminescence intensity of the PUFX–Tb3+ complex increased up to 10‐fold after adding DNA. The excitation and emission wavelengths were 345 and 545 nm, respectively. Under optimum conditions, variations in the fluorescence intensity showed a good linear relationship with the concentration of hsDNA in the range of 3.0 × 10‐9 to 1.0 × 10‐6 g/mL, with a correlation coefficient (R) of 0.997, and the detection limit was 2.1 × 10‐9 g/mL. The method was successfully applied to the determination of DNA in synthetic samples, and recoveries were in the range 97.3–102.0%. The mechanism of fluorescence enhancement of the PUFX–Tb3+ complex by DNA is also discussed. The mechanism may involve formation of a ternary complex mainly by intercalation binding together with weak electrostatic interaction, which will increase the energy transition from ligand to Tb3+, increasing the rigidity of the complex, and decreasing the radiationless energy loss through O–H vibration of the H2O molecule in the PUFX–Tb3+ compl+osed method is not only more robust and friendly to the environment, but also of relatively higher sensitivity. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

8.
A coordination polymer {[Tb4(3-SBA)4(OH)4(phen)3(H2O)3] · 7H2O}n (3-SBA = 3-sulfobenzoate, phen = 1,10-phenanthroline) was synthesized and structurally characterized. The complex contains cubane-like clusters, [Tb43-OH)4(phen)3(H2O)3]8+, which are further linked through 3-SBA ligands to form a 2-D grid-like network structure with topology of (33, 44, 53). The complex exhibits strong photoluminescence of the Tb3+ ion.  相似文献   

9.
In this study, a series of LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) down‐converting phosphors were synthesized using a modified sol–gel combustion method, and their photoluminescence (PL) properties were investigated as a function of activator concentration and annealing temperature. The resultant particles were characterized using X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, UV/Vis diffuse reflectance spectroscopy and PL spectra. The highly crystalline LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) phosphors with an average size of 200–300 nm obtained at 1100°C have an orthorhombic aeschynite‐type structure and exhibit the highest luminescent intensity in our study range. The emission spectra of LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) phosphors under excitations at UV/blue sources are mainly composed of characteristic peaks arising from the f–f transitions of RE3+, including 489 nm (5D47F6) and 545 nm (5D47F5) for Tb3+, 476 and 482 nm (4F9/26H15/2) and 571 nm (4F9/26H13/2) for Dy3+, and 545 nm (5F4 + 5S25I8) for Ho3+, respectively. The luminescent mechanisms were further investigated. It can be expected that these phosphors are of intense interest and potential importance for many optical applications. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

10.
A flow injection chemiluminescence (FI–CL) method was developed for the determination of cyanide (CN) based on the recovered CL signal by Cu2+ inhibiting a glutathione (GSH)‐capped CdTe quantum dot (QD) and hydrogen peroxide system. In an alkaline medium, strong CL signals were observed from the reaction of CdTe QDs and H2O2, and addition of Cu2+ could cause significant CL inhibition of the CdTe QDs–H2O2 system. In the presence of CN, Cu2+ can be removed from the surface of CdTe QDs via the formation of particularly stable [Cu(CN)n](n‐1)– species, and the CL signal of the CdTe QDs–H2O2 system was efficiently recovered. Thus, the CL signals of CdTe QDs–H2O2 system were turned off and turned on by the addition of Cu2+ and CN, respectively. Further, the results showed that among the tested ions, only CN could recover the CL signal, which suggested that the CdTe QDs–H2O2–Cu2+ CL system had highly selectivity for CN. Under optimum conditions, the CL intensity and the concentration of CN show a good linear relationship in the range 0.0–650.0 ng/mL (R2 = 0.9996). The limit of detection for CN was 6.0 ng/mL (3σ). This method has been applied to detect CN in river water and industrial wastewater with satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

11.
A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra‐(3‐methoxy‐4‐hydroxyphenyl)]–Tb3+ [T(3‐MO‐4HP)–Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3‐MO‐4HP)–Tb3+ porphyrin in the presence of bis(2‐ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris–HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05–3.00 µg mL?1 for calf thymus DNA (ct DNA) and 0.03–4.80 µg mL?1 for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 µg mL?1, respectively. In addition, the binding interaction mechanism between T(3‐MO‐4HP)–Tb3+ porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

12.
In this study, d ‐penicillamine‐functionalized graphene quantum dots (DPA‐GQD) has been synthesized, which significantly increases the fluorescence intensity of GQD. We used this simple fluorescent probe for metal ions detection in human plasma samples. Designed DPA‐GQD respond to Hg2+, Cu2+, Au2+, Ag+, Co2+, Zn2+, and Pb2+ with high sensitivity. The fluorescence intensity of this probe decreased significantly in the presence of metal ions such as, Hg2+, Cu2+, Au2+, Ag+, Co2+, Zn2+, and Pb2+. In this work, a promising probe for ions monitoring was introduced. Moreover, DPA‐GQD probe has been tested in plasma samples. The functionalized DPA‐GQDs exhibits great promise as an alternative to previous fluorescent probes for bio‐labeling, sensing, and other biomedical applications in aqueous solution.  相似文献   

13.
A sensitive and convenient flow‐injection chemiluminescence (FI‐CL) turn‐on assay for alkaline phosphatase (ALP) activity without any label and synthesis is developed. Cu2+ can catalyze the luminol–H2O2 CL reaction. Pyrophosphate (PPi) can chelate Cu2+ and therefore the Cu2+‐mediated luminol‐H2O2 CL reaction is inhibited. The addition of ALP can catalyze the hydrolysis of PPi into phosphate ions, Cu2+ is released and the chemiluminescence recovers. A detection limit of 1 mU/mL ALP is obtained.  相似文献   

14.
A new 2,5‐diphenyl‐1,3,4‐oxadiazole‐based derivative (L) was synthesized and applied as a highly selective and sensitive fluorescent sensor for relay recognition of Cu2+ and S2? in water (Tris–HCl 10 mM, pH = 7.0) solution. L exhibits an excellent selectivity to Cu2+ over other examined metal ions with a prominent fluorescence ‘turn‐off’ at 392 nm. L interacts with Cu2+ through a 1:2 binding stoichiometry with a detection limit of 4.8 × 10–7 M. The on‐site formed L–2Cu2+ complex exhibits excellent selectivity to S2? with a fluorescence ‘off–on’ response via a Cu2+ displacement approach. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

15.
The synthesis and X-ray crystal structure of the complex {[CuII(Ph2PBPT)(bpy)](ClO4)2 · 2DMF} where Ph2PBPT=4,4-(1,4-phenylene)bis[3-phenyl-5-(2-pyridyl)-4H-1,2,4-triazole], bpy=2,2-bipyridine and DMF=N,N-dimethylformamide are reported. In this one-dimensional coordination polymer the Cu2+ ions are in a distorted octahedral N6 coordination environment made up of two Ph2PBPT molecules, each chelating via one pyridine and one triazole nitrogen, and one bpy co-ligand. Within the zig-zag chain thus formed the shortest distance between two metal centres across the Ph2PBPT ligand is 13.305(3) Å while it is 10.009(3) Å between two chains. This complex represents the first structurally characterised example of a coordination compound incorporating a chelating 4,4-bis(4H-1,2,4-triazole) as a ligand.  相似文献   

16.
A sensitive time‐resolved luminescence method for the determination of amlodipine (AM) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+) by formation of a ternary complex with AM in the presence of tri‐n‐octylphosphine oxide (TOPO) as co‐ligand, dodecylbenzenesulfate as surfactant and europium ion as a co‐luminescence reagent. The signal for Tb–AM–TOPO is monitored at λex = 242 nm and λem = 550 nm. Optimum conditions for the formation of the complex in aqueous system were 0.015 m Tris (hydroxylmethyl) amino methane buffer, pH 9.0, TOPO (1.0 × 10–4 m ), Eu3+ (2.0 × 10–7 m ), dodecylbenzenesulfate (0.14%) and 6.0 × 10–5 m of Tb3+, which allows the determination of 10–50 ppb of AM with a limit of detection of 1.2 ppb. The relative standard deviations of the method range between 0.1 and 0.2% indicated excellent reproducibility of the method. The proposed method was successfully applied for the assay of AM in pharmaceutical formulations and in plasma samples. Average recoveries of 98.5 ± 0.2% and 95.2 ± 0.2% were obtained for AM in tablet and plasma samples respectively. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

17.
In aqueous solution, the reaction of Cu(ClO4)2 and di(2-pyridylmethyl)amine, DPA with the disodium salt of pyrazole-3,5-dicarboxylate (Na2Hpzdc) in presence of sodium azide afforded the azido complex [Cu3(DPA)3(μ-pzdc)(μ-N3)](ClO4)2·2H2O (1) whereas when reaction was conducted in absence of sodium azide the perchlorato complex [Cu3(DPA)3(μ-pzdc)(μ-ClO4)](ClO4)2·3H2O (2) was obtained. The complexes were structurally characterized by physicochemical techniques and by single crystal X-ray crystallography in case of 1. The coordination sphere of the two complexes which are iso-structural polymeric 1D systems consist of three independent Cu(DPA) units, one pzdc bridging ligand and one end-on bridging azido group in 1 or one bridging perchlorato group in 2. The three Cu(II) centers in both complexes may be described as axially elongated octahedral. Magnetic susceptibility measurements reveal the weak anti-ferromagnetic coupling in the two complexes (= −23.2 cm−1 for 1 and −14.8 cm−1 for 2).  相似文献   

18.
In this paper, a novel fluorescent sensor 1 for selective and sensitive detection of cysteine was developed based on a complex between bi‐8‐carboxamidoquinoline derivative ligand ( L ) and Cu2+. The interaction of Cu2+ with the ligand causes a dramatic fluorescence quenching most likely due to its high affinity towards Cu2+ and a ligand–metal charge transfer (LMCT) process. The in situ generated L–Cu 2 complex was utilized as a chemosensing ensemble for cysteine. In the presence of cysteine, the fluorophore, L , was released from L–Cu 2 complex because of the strong affinity of cysteine to Cu2+ via the Cu–S bond, leading to the fluorescence recovery of the ligand. The proposed displacement mechanism was confirmed by the results of mass spectrometry (MS) study. Under optimized conditions, the recovered fluorescence intensity is linear with cysteine concentrations in the range 1 × 10?6 mol/l to 8 × 10?6 mol/l. The detection limit for cysteine is 1.92 × 10?7 mol/l. Furthermore, the established method showed a highly sensitive and selective response to cysteine among the 20 fundamental α‐amino acids used as the building blocks of proteins, after Ni2+ was used as a masking agent to eliminate the interference of His. The proposed sensor is applicable in monitoring cysteine in practical samples with good recovery rate.  相似文献   

19.
Four series of borosilicate glasses modified by alkali oxides and doped with Tb3+ and Sm3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B2O3 + 10SiO2 + 5MgO + R + 0.5(Tb2O3/Sm2O3) [where R = 10(Li2O /Na2O/K2O) for series A and C, and R = 5(Li2O + Na2O/Li2O + K2O/K2O + Na2O) for series B and D]. The X‐ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5D47F5 (543 nm) transition of the Tb3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm3+ ions with the series C and D glasses showed strong reddish‐orange emission at 600 nm (4G5/26H7/2) with an excitation wavelength λexci = 404 nm (6H5/24F7/2). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb3+ and Sm3+ ions was studied to optimize the potential alkali‐oxide‐modified borosilicate glass.  相似文献   

20.
Latent fingerprints (LFPs) are one among the most important types of evidences at crime scenes because of the distinctiveness and tenacity of the friction ridges in fingerprints (FPs). Therefore, it is essential in forensic science to develop a reliable method to detect LFPs. Traditional detection methods still face a number of difficulties, such as limited sensitivity, low contrast, strong background, and complex processing stages. In this study, MgO-ZrO2:Tb3+ (1–5 mol%) (MZ:Tb) nanocomposites (NCs) were prepared via a simple solution combustion (SC) method at low temperature. The photoluminescence (PL) investigation demonstrates that when excited at 379 nm, the produced NCs emits distinctive emission peaks of terbium ions (Tb3+). According to the photometric results, the NCs can be employed as warm light NCs and emit light in the green portion of the colour spectrum. The estimated optical band gap from diffuse reflectance spectra is found to be in the range 4.84–4.97 eV. Regardless of the type of surface being used, the optimized MgO-ZrO2:Tb3+ (4 mol%) (MZ:4Tb) NCs has a strong ability to minimize background fluorescence interference. With high contrast LFP and I–V type of cheiloscopy, these NCs present a flexible fluorescent mark for the identification of levels 1–3 details in forensic investigation.  相似文献   

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