Effects of La3+ and Eu3+ on outward potassium channels (Kout+) in Vicia guard cells have been studied by patch clamping technique. Extracellular La3+ inhibited Kout+ currents with a half-inhibition concentration (IC50) of 81 μmol·L−1. Interestingly, intracellular La3+ activated Kout+ currents at a free concentration of 1.13 × 10−14 mol·L−1, and inhibited Kout+ currents at a free concentration of 5.86 × 10−14 mol·L−1. Extracellular Eu3+ also activated Kout+ currents at concentrations of 10 μmol·L−1 and 50 μmol·L−1, and inhibited Kout+ currents at concentrations of more than 1 mmol·L−1. The effects of La3+ and Eu3+ on Kout+ currents may contribute to regulation of the plant water status, which may be one of the mechanisms of the biological effect
of rare earth elements. 相似文献
A new tripodal rhodamine B derivative 2 was designed and synthesized by tripodal trialdehyde and rhodamine B hydrazide for
the first time. This derivative could be used as a fluorescent chemosensor for the selective and sensitive determination of
copper(II) in Tris-HCl buffer and ethanol aqueous mixed media. Under the optimum conditions described herein, fluorescence
enhancement at 557/577 nm was linearly related to the concentration of copper(II) in the range of 0.10 to 10.00×10−5 mol·L−1, with a correlation coefficient of R2=0.9964 (n=15) and a detection limit of 1.129×10−7 mol·L−1 (the relative standard deviation for five repeated measurements at 4.00×10−5 mol·L−1 Cu(II) was 2.2%). The absorbance measurements at 557 nm were linearly related to the concentration of Cu(II) in the range
of 0.50 to 25.00×10−5 mol·L−1, with a correlation coefficient of R2=0.9948 (n=13) and a detection limit of 3.338×10−7mol·L−1.
Supported by the Foundation of the Governor of Guizhou Province, China (Grant No. 200617) and the Talented Person Foundation
of Guizhou University (Grant No. 2007039) 相似文献
Spiropyrans are the most studied families of func- tional materials due to their reversible structural con- version in response to external optical, chemical, and thermal stimulation[1]. Irradiation with ultraviolet light causes formation of an extended π-conjugation open form (merocyanine form) by heterolytic cleavage of the C (spiro)-O bond, which generates an intense ab- sorption in the visible region. Under the irradiating of visible light, the opened form will come back to the closed spi… 相似文献
Since the copper ions (Cu2+) play a fatal role in many foundational physiological processes, it is important to develop a simple, highly sensitive and selective sensor for Cu2+ detection in living systems. Herein, an intramolecular charge transfer (ICT) and dansyl-based fluorescent chemosensor 1 was designed, synthesized and characterized for the sensitive and selective quantification of Cu2+. It exhibited remarkable fluorescence quenching upon addition of Cu2+ over other selected metal ions, attributed to the complex formation between 1 and Cu2+ with the association constant 6.7 × 105 M?1. The sensor 1 showed a fast and linear response towards Cu2+ in the concentration range from 0 to 12.5 × 10?6 mol L?1 with the detection limit of 2.5 × 10?7 mol L?1. This detection could be carried out in a wide pH range of 5.0–14. Furthermore, sensor 1 can be used for detecting Cu2+ in living cells. 相似文献
2,2′‐Bisbenzimidazole derivative ( L ) was designed as a fluorescent chemosensor for Fe3+. This structurally simple chemosensor displays significant fluorescence quenching with increasing concentrations of Fe3+. L exhibited high selectivity and antidisturbance for Fe3+ among environmentally relevant metal ions in aqueous media. The method of Job's plot indicated the formation of 1:2 complex between L and Fe3+, and the possible binding mode of the system was also proposed. In addition, further study demonstrates the detection limit on fluorescence response of the sensor to Fe3+ is down to 10?7 mol·L?1 range. The binding mode was investigated by fluorescence spectra, ESI‐MS, IR data, 1H NMR, 13C NMR and crystal data. 相似文献
A new 1,8‐naphthalimide‐based fluorescence “turn off” chemosensor, N‐phenyl‐4‐(3,3′‐((2‐aminoethyl)azanediyl)dipropanoic acid)‐1,8‐naphthalimide ( MAST ), for the detection of Cu2+ was synthesized. Upon treatment with Cu2+, in coexistence with various competitive metal ions in HEPES‐buffered dimethylsulfoxide (DMSO) solution (v/v, 1:1; pH 7.4), MAST displayed a high selectivity toward Cu2+ with a fluorescence quenching of 83.67%. Additionally, a good linear response of MAST for the detection of Cu2+ was obtained in the concentration range of 10 × 10−6 to 50 × 10−6 M. A 1:1 stoichiometric interaction of MAST with Cu2+ was observed, and the association constant and detection limit were calculated to be 1.37 × 106 and 0.69 × 10−8 M, respectively. The sensing mechanism of the chemosensor toward Cu2+ was proposed due to the effect of the paramagnetic nature of Cu2+ and reverse‐photo‐induced electron transfer (PET) process. Ultimately, the proposed chemosensor was applied to quantify Cu2+ in real‐world water samples, with excellent recovery rates of 98.00–109.80% observed. 相似文献
A novel 1,8-naphthalimide dye with simple structure has been produced by a facile synthetic method for colorimetric and fluorescent sensing of H+ and Cu2+. In CH3CN/H2O (1/1, v/v), the dye could monitor H+ using dual channels (ratiometric absorbance and fluorescence intensity change) from pH 6.2 to 12.0. Meanwhile, in the pH range of 1.9–5.2, the dye could also be used to detect Cu2+ using triple channels [ultraviolet–visible (UV–Vis) absorption, fluorescence intensity reduction, as well as fluorescence blueshift]. The detection limits for Cu2+ evaluated by colorimetric and fluorescent titration were 6.10 × 10?7 and 2.62 × 10?7 M, respectively. The dye exhibited specific selectivity and sensitivity for H+ and Cu2+ over various coexisting metal ions. Moreover, the sensing mechanism of the dye for H+ and Cu2+ was carefully examined. 相似文献
A rhodamine-conjugated coumarin (L) was used in designing a selective fluorescence chemosensor for the determination of trace amounts of Cr3+ ions in acetonitrile–water (MeCN/H2O (90:10, %v/v) solutions. The intensity of the fluoresce emission of the chemosensor is intensified upon addition of Cr3+ ions in MeCN/H2O (90:10, %v/v) solutions, due to the formation of a selective 1:1 complex between L and Cr3+ ions. The fluorescence enhancement versus Cr3+ concentration has been found to be linear from 1.0?×?10?7 to 1.8?×?10?5 M and a detection limit of 7.5?×?10?8 M. The proposed fluorescent probe proved to be highly selective towards Cr3+ ions as compared to other common metal ions and could be successfully applied to the determination of Cr3+ concentrations in some water and wastewater samples. 相似文献
New imidazole‐functionalized disubstituted polyacetylene was synthesized by utilizing the postfunctional strategy. In addition, its ability to sense copper ions and α‐amino acids by fluorescence quenching has been studied. The quenching of the fluorescence of the imidazole‐functionalized disubstituted polyacetylene was observed at a very low level of Cu2+ (7.0 × 10−7 mol · L−1). The fluorescent intensity decreased rapidly upon the increase of the concentration of the added solution of Cu2+. It was expected that the addition of α‐amino acids to the solution of the polyacetylene/Cu2+ complex could turn on the fluorescence of the polyacetylene, if α‐amino acids could remove the copper ions from the complex. Glycine, was used for testing: upon the addition of glycine the quenched fluorescence of P1 turned on immediately. The detection limit was as low as 6.0 × 10−5 mol · L−1.
A novel fluorescent chemosensor, (E)-7-(diethylamino)-3-((2-phenylimidazo[1,2-a]pyridin-3-ylimino)methyl)-2H-chromen-2-one 1a, has been synthesised and characterised. This chemosensor displayed an extreme selective fluorescence emission only with Cu2+ ion over all other metal ions examined. The Job’s plot experiment analysis suggested the binding ratio of the chemosensor 1a with Cu2+ was 1:1 metal-to-ligand ratio. The association constant for Cu2+ towards receptor 1a obtained from Benesi–Hildebrand plot was found to be 4.859 × 103 M?1 with a detection limit 4.6 × 10?8 M. Fluorescence enhancement caused by Cu2+ binding with chemosensor 1a attributed to combinational effect of intramolecular charge transfer and chelation-enhanced fluorescence occurred at pH 8.0. 相似文献
In this work, we design and synthesize the novel probe RC through introduction the 1-aza-4,13-dithia-15-crown-5 ring into the structure of rhodamine 6G hydrazide, where the N atom of crown ring is responsible for quenching of rhodamine fluorescence. The compound obtained behaves as multifunctional cation sensor providing selective fluorescent response to Au3+ and selective colorimetric response to Cu2+ ions in aqueous acetonitrile (1/1, v/v) at pH 7.0. The use of 10?5?M RC solution allowed reliable determination of target cations in the presence of a wide range of environmentally relevant ions with detection limits of 2?×?10?6?M and 5?×?10?7?M for gold and copper, respectively. 相似文献
Solubility product (Lu(OH)3(s)⇆Lu3++3OH−) and first hydrolysis (Lu3++H2O⇆Lu(OH)2++H+) constants were determined for an initial lutetium concentration range from 3.72·10−5 mol·dm−3 to 2.09·10−3 mol·dm−3. Measurements were made in 2 mol·dm−3 NaClO4 ionic strength, under CO2-free conditions and temperature was controlled at 303 K. Solubility diagrams (pLuaq vs. pCH) were determined by means of a radiochemical method using 177Lu. The pCH for the beginning of precipitation and solubility product constant were determined from these diagrams and both the first
hydrolysis and solubility product constants were calculated by fitting the diagrams to the solubility equation. The pCH values of precipitation increases inversely to [Lu3+]initial and the values for the first hydrolysis and solubility product constants were log10β*Lu,H = −7.92±0.07 and log10K*sp,Lu(OH)3 = −23.37±0.14. Individual solubility values for pCH range between the beginning of precipitation and 8.5 were SLu3+ = 3.5·10−7 mol·dm−3, SLu(OH)2+ = 6.2·10−7 mol·dm−3, and then total solubility was 9.7·10−7 mol·dm−3. 相似文献
In this study, we have successfully synthesized a new coumarin based fluorescent chemosensor 1, in which tren and quinolone are introduced as receptors for sequential recognition of Cu2+ and PPi. The structure of chemosensor 1 was characterized by 1H NMR, 13C NMR and ESI-HR-MS. Sensor 1 showed an obvious “on-off” fluorescence quenching response toward Cu2+, and the quenching efficiency reached a maximum of 99.6% with the addition of 20 equiv. of Cu2+. The 1-Cu2+ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions, especially HPO42? and H2PO4?. The detection limit of sensor 1 was 1.9?×?10?6?M to Cu2+ and 5.96?×?10?8?M to PPi. In addition, sensor 1 showed a 1:1 binding stoichiometry to Cu2+ and sensor 1-Cu2+ showed a 2: 1 binding stoichiometry to PPi in CH3CN/HEPES buffer medium (9:1 v/v, pH?=?7.4). The stable pH range of sensor 1 to Cu2+ and 1-Cu2+ to PPi was from 4 to 8. 相似文献
A novel flow injection procedure has been developed for the determination of tannic acid based on the inhibition of the chemiluminescences
in luminol-H2O2-Manganese tetrasulfonatophthalocyanine (MnTSPc) system by tannic acid. The method is simple, rapid and sensitive with a detection
limit of 8 × 10−10 mol·L−1 and a linear range of 7 × 10−9–5 × 10−6 mol·L−1. The relative standard deviation is 1.9% for eleven measurements of 5 × 10−7 mol·L−1 tannic acid. The method has been successfully applied to the determination of tannic acid in real Chinese gall and hop pellets
samples. 相似文献
A new fluorescent sensor (1) for Pb2+ containing a 1,4-dicyano-2,5-bis(styryl)benzene fluorophore and 2-(N,N′-bis(carboxylmethyl))amino-1-carboxylmethoxylbenzene as receptor has been synthesized. The sensor selectively responds to
Pb2+ in the aqueous environment, and brings about similar and significant changes in one- and two-photon excited emission spectra:
λmax red-shift from 460 (519) to 590 nm. The selective response is pH-independent in a large physiological pH range, and two-photon
action cross section (ϕδ) is 51 GM (1 GM = 1×10−50 cm4·s·photon−1·molecule−1) at 740 nm.
Supported by the National Natural Science Foundation of China (Grant Nos. 20705621 & 20706008), the National Basic Research
Project of China (Grant No. 2009CB724706), the Ministry of Education of China, Changjiang Scholars Innovative Research Team
in University (Grant No. IRT0711) and Cultivation Fund of the Key Scientific and Technical Innovation Project (Grant No. 707016) 相似文献