共查询到20条相似文献,搜索用时 0 毫秒
1.
Zhihong XuAuthor Vitae Like ZhangAuthor VitaeRui GuoAuthor Vitae Tiancheng XiangAuthor VitaeChangzeng WuAuthor Vitae Zhi ZhengAuthor VitaeFengling YangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):546-552
A new rhodamine B derivative colorimetric and fluorescent sensor (1) was synthesized by condensation reaction of rhodamine B hydrazide and 2,4-dihydroxybenzaldehyde, which showed reversible and highly selective and sensitive recognition toward Cu2+ over other examined metal ions. Upon addition of Cu2+, sensor 1 exhibits remarkably enhanced absorbance intensity and color change from colorless to pink in DMSO and MeCN aqueous buffer solution or pure MeCN, and shows significant off-on fluorescence accompanied by color changes from colorless to orange in MeCN. The sensor 1 was also successfully applied to the determination of Cu2+ in water samples. 相似文献
2.
Yu WangAuthor Vitae XueYan HuAuthor VitaeLei WangAuthor Vitae ZhuoBin ShangAuthor VitaeJianBin ChaoAuthor Vitae WeiJun JinAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):126-131
A new acridine fluoroionophore containing two diethanolamine ligands, 4,5-bis(N,N-di (2-hydroxyethyl)iminomethyl)acridine (BHIA), was designed and synthesized based on the fluorophore-spacer-receptor format. And its fluorescent sensing behavior towards metal ions was investigated in buffered aqueous media. The presence of Cd2+ induces the formation of a 1:1 ligand/metal complex at neutral pH, which exhibits enhanced emission at 454 nm. The fluorescence intensity is linear with the Cd2+ concentration in the range of 1.0 × 10−6 to 3.0 × 10−5 M (R = 0.9967). Experimental results show a low interference response towards other metal ions. The selective switch-on fluorescence response of BHIA to Cd2+ makes it suitable for sensing of Cd2+ in aqueous solution. The detection limit is 1.3 × 10−7 M. Moreover, the results indicated that BHIA was a reversible chemosensor for Cd2+, which makes it attractive for sensing applications. 相似文献
3.
Single quantum dot-micelles coated with gemini surfactant for selective recognition of a cation and an anion in aqueous solutions 总被引:3,自引:0,他引:3
The synthesis of quantum dot coated with cetyltrimethyl ammonium bromide (CTAB) and gemini surfactant [C12H25N+(CH3)2(CH2)4(CH3)2N+C12H25]·2Br− (C12-4-12) in aqueous solution have been described. It is characterized by photoluminescent spectroscopy, UV–vis spectroscopy and transmission electron microscopy (TEM), etc. In comparison with CTAB-coated QDs, the QDs coated with C12-4-12 respond selectively to both transition metal ion copper and fluoride ion in aqueous media. When Cu2+ is bound to C12-4-12-coated QD micelles, the fluorescence intensity is quenched. Linear relationships are found between the relative fluorescence intensity and the concentration of Cu2+ in the range 0–500 μM, which is best described by a Stern–Volmer-type equation. Meanwhile, it is found that F− enhanced the luminescence of the C12-4-12-coated QD micelles in a concentration dependence that is described by a Langmuir binding isotherm equation in the range 0–300 μM. The limits of detection of Cu2+ and F− are 1.1 and 0.68 μM, respectively. The possible mechanism is discussed. 相似文献
4.
采用深海适冷菌Pseudoalteromonas sp. SM9913分泌的胞外多糖(EPS)分别对Pb2+和Cu2+进行吸附,研究了多糖用量、pH、吸附时间和共存离子对EPS吸附性能的影响及EPS对Pb2+和Cu2+的吸附热力学.结果表明,EPS对Pb2+和Cu2+的吸附量随EPS投加量的增加而减小.EPS对Pb2+和Cu2+的最佳吸附pH分别为4.5~5.5和4.5~6.0. EPS对Cu2+的吸附平衡时间为90 min,对Pb2+的吸附平衡时间则长达180 min.共存离子Ca2+、Mg2+、Na+、K+的加入均降低了EPS对Pb2+的吸附量,Ca2+、Mg2+的加入降低了EPS对Cu2+的吸附量,但低浓度的Na+和实验范围浓度的K+不仅没有降低反而增加了EPS对Cu2+的吸附量.Freundlich和Dubinin-Radushkevich方程均能较好地描述SM9913胞外多糖吸附Pb2+和Cu2+的热力学过程,由Dubinin-Radushkevich方程得到SM9913胞外多糖对Pb2+和Cu2+的最大吸附量分别为243.3 mg/g (10℃) 和36.7 mg/g (40℃).胞外多糖吸附金属离子前后的红外光谱分析表明,多聚糖中C—O—C、乙酰基和羟基是起主要吸附作用的官能团. 相似文献
5.
A series of Bi3+ and Gd3+ doped ZnB2O4 phosphors were synthesized with solid state reaction technique. X-ray diffraction technique was employed to study the structure of prepared samples. Excitation and emission spectra were recorded to investigate the luminescence properties of phosphors. The doping of Bi3+ or Gd3+ with a small amount (no more than 3 mol%) does not change the structure of prepared samples remarkably. Bi3+ in ZnB2O4 can emit intense broad-band purplish blue light peaking at 428 nm under the excitation of a broad-band peaking at 329 nm. The optimal doping concentration of Bi3+ is experimentally ascertained to be 0.5 mol%. The decay time of Bi3+ in ZnB2O4 changes from 0.88 to 1.69 ms. Gd3+ in ZnB2O4 can be excited with 254 nm ultraviolet light and yield intense 312 nm emission. The optimal doping concentration of Gd3+ is experimentally ascertained to be 5 mol%. The decay time of Gd3+ in ZnB2O4 changes from 0.42 to 1.36 ms. 相似文献
6.
Syed M. Usman AliAuthor Vitae N.H. AlviAuthor VitaeZafar IbupotoAuthor Vitae Omer NurAuthor VitaeMagnus WillanderAuthor Vitae Bengt DanielssonAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):241-247
In this study, a potentiometric uric acid biosensor was fabricated by immobilization of uricase onto zinc oxide (ZnO) nanowires. Zinc oxide nanowires with 80-150 nm in diameter and 900 nm to 1.5 μm in lengths were grown on the surface of a gold coated flexible plastic substrate. Uricase was electrostatically immobilized on the surface of well aligned ZnO nanowires resulting in a sensitive, selective, stable and reproducible uric acid biosensor. The potentiometric response of the ZnO sensor vs Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (1-650 μM) suitable for human blood serum. By applying a Nafion® membrane on the sensor the linear range could be extended to 1-1000 μM at the expense of an increased response time from 6.25 s to less than 9 s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea. 相似文献
7.
In this paper, DNA–Cu2+ complex was electrodeposited onto the surface of glassy carbon (GC) electrode, which fabricated a DNA–Cu2+/GC electrode sensor to detect H2O2 with nonenzyme. Cyclic voltammogram of DNA–Cu2+/GC electrode showed a pair of well-defined redox peaks for Cu2+/Cu+. Moreover, the electrodeposited DNA–Cu2+ complex exhibited excellent electrocatalytic behavior and good stability for the detection of H2O2. The effects of Cu2+ concentration, electrodeposition time and determination conditions such as pH value, applied potential on the current response of the DNA–Cu2+/GC electrode toward H2O2 were optimized to obtain the maximal sensitivity. The linear range for the detection of H2O2 is 8.0 × 10−7 M to 4.5 × 10−3 M with a high sensitivity of −40.25 μA mM−1, a low detection limit of 2.5 × 10−7 M and a fast response time of within 4 s. In addition, the sensor has good reproducibility and long-term stability and is interference free. 相似文献
8.
A simple and reliable method was proposed for preparing a selective dopamine (DA) sensor based on a molecularly imprinted electropolymer of o-aminophenol. The sensor is selective for the determination of DA in the presence of high concentrations of ascorbic acid (AA), with a maximum molar ratio of 1/1000. The molecular imprinted (MIP) sensor was tested by cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV) to verify the changes in oxidative currents of ferricyanide. In optimized conditions, DA at concentrations of 2 × 10−8 to 0.25 × 10−6 mol/L could be determined with a detection limit of 1.98 × 10−9 mol/L (S/N = 3). The MIP sensor showed high selectivity, sensitivity, and reproducibility. Determination of DA in simulated samples of dopamine hydrochloride showed good recovery. 相似文献
9.
A very sensitive, highly selective and reversible optical chemical sensor (optode) for mercury ion is described. The sensor is based on the interaction of Hg2+ with 2-mercapto-2-thiazoline (MTZ) in plasticized PVC membrane incorporating a proton-selective chromoionophore (ETH5294) and lipophilic anionic sites (sodium tetraphenylborate, NaTPB). The membranes were cast onto glass substrates and used for the determination of mercury ion in aqueous solutions by batch and flow-through methods. The sensor could be used in the range 2.0 × 10−10 to 1.5 × 10−5 M (0.04 ng mL−1 to 3 μg mL−1) Hg2+ with a detection limit of 5.0 × 10−11 M and a response time of <40 s. It can be easily and completely regenerated by dilute nitric acid solution. The sensor has been incorporated into a home-made flow-through cell for determination of mercury ion in flowing streams with improved sensitivity, precision and detection limit. The sensor showed excellent selectivity for Hg2+ with respect to several common alkali, alkaline earth and transition metal ions. The results obtained for the determination of mercury ion in river water samples using the proposed optode was found to be comparable with the well-established cold-vapor atomic absorption method. 相似文献
10.
Ling-Fei Zhang Jiang-Lin Zhao Xi Zeng Lan Mu Xue-Kai Jiang Min Deng Jian-Xin Zhang Gang WeiAuthor vitae 《Sensors and actuators. B, Chemical》2011,160(1):662
A simple structure, a rhodamine fluorescent derivative, was synthesized easily by a one-step condensation reaction of rhodamine B ethylenediamine and acetylacetone. Its structure was characterized by X-ray crystallography, NMR, MS and IR spectroscopy. As a bi-functional and highly selective “OFF–ON” chemosensor for Fe3+ or Cu2+, the derivative displayed a selective fluorescence enhancement effect only with Fe3+ and an absorption enhancement effect only with Cu2+ by modulating the pH value. In an aqueous ethanol medium, Fe3+ formed a 1:1 complex with the derivative at pH 6, while Cu2+ formed a 1:1 complex at pH 8.5. The limits of detection of the ions were low: 3.9 × 10−9 and 4.8 × 10−8 mol L−1. The derivative also functioned as a fluorescence sensor for CT-DNA, in which the Fe3+ ion that was used as a bridge between the derivative and DNA forming a ternary complex. 相似文献
11.
Zhimin LiuAuthor Vitae Zhenling WangAuthor VitaeYanyan CaoAuthor Vitae Yanfeng JingAuthor VitaeYanli LiuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):540-546
A novel nanocomposite, comprising of graphene sheet (GS) and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), was developed on the glassy carbon electrode (GCE) for the simultaneous determination of hydroquinone and catechol in 0.10 M acetate buffer solution (pH 5.0). At the GS/BMIMPF6/GCE, both hydroquinone and catechol can cause a pair of quasi-reversible and well-defined redox peaks. In comparison with bare GCE and GS modified electrode, GS/BMIMPF6/GCE showed larger peak currents, which was related to the higher specific surface area of graphene and high ionic conductivity of BMIMPF6. Under the optimized condition, the cathodic peak current were linear over ranges from 5.0 × 10−7 M to 5.0 × 10−5 M for hydroquinone and from 5.0 × 10−7 M to 5.0 × 10−5 M for catechol, with the detection limits of 1.0 × 10−8 M and 2.0 × 10−8 M, respectively. The proposed method was successfully applied to the simultaneous determination of hydroquinone and catechol in artificial sample, and the results are satisfactory. 相似文献
12.
Zhi-Qiang HuAuthor Vitae Yong-Cheng FengAuthor VitaeHe-Qing HuangAuthor Vitae Lei DingAuthor VitaeXiao-Ming WangAuthor Vitae Cun-Sheng LinAuthor VitaeMing LiAuthor Vitae Cui-Ping MaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):428-432
A Rhodamine-based fluorescent and colorimetric chemosensor for Fe3+ ion, acetyl rhodamine-hydroxamate (ARH), was designed and synthesized. Upon mixed with Fe3+ in CH3CN-H2O (1:1, v/v), the spirolactam of ARH was opened, which resulted in the dramatic enhancement of both fluorescence and absorbance intensity as well as the color change of the solution. Background metal ions showed small or no interference with the detection of Fe3+. The Job's plot indicated the formation of 1:1 complex between ARH and Fe3+. Confocal laser scanning microscopy experiments showed that ARH could be used to detect Fe3+ in living cells. 相似文献
13.
Guoqiang YangAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):848-853
A new fluorescent excited state intramolecular proton transfer compound, 2-(2-hydroxy-4-carbaldehydephenyl)benzoxazole (HCPBO), has been synthesized for the detection of Cu2+, based on its fluorescence quenching. In molecular monodispersed solution, the recognition selectivity for Cu2+ was poor as Co2+ and Ni2+ gave similar results in fluorescence quenching. However, the nanoparticles of HCPBO, prepared in ethanol-water (1:4, v/v), greatly enhanced the recognition selectivity for Cu2+. The mechanism was discussed as energy transfer (ET), energy migration (EM) and the more quantity of formed HCPBO-Cu2+ complex than other metal ions in the nanoparticle conditions enhanced the recognition selectivity for Cu2+ together. 相似文献
14.
Nur AksunerAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):162-168
A new sensor membrane based on a novel triazolo-thiadiazin derivative immobilized in polyvinyl chloride has been developed for the determination of Pb(II) ions that displays excellent performance. The parameters involved in the preparation of the optode and determination of Pb(II) were optimized. Under the optimal conditions, the proposed sensor displays a calibration response for Pb(II) over a wide concentration range of 5.0 × 10−8 to 3.8 × 10−4 M with the detection limit of 2.2 × 10−8 M. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity over common metal ions. The optode membrane developed is easily prepared, stable, rapid, and simple for the determination of Pb(II). The accuracy of the proposed sensor was confirmed by analyzing standard reference materials of natural water and surface water. The sensor was successfully used for the determination of Pb(II) ions in water samples with satisfactory results. 相似文献
15.
R. PearceAuthor Vitae T. IakimovM. AnderssonAuthor Vitae L. HultmanAuthor VitaeA. Lloyd SpetzAuthor Vitae R. YakimovaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):451-455
Epitaxially grown single layer and multi layer graphene on SiC devices were fabricated and compared for response towards NO2. Due to electron donation from SiC, single layer graphene is n-type with a very low carrier concentration. The choice of substrate is demonstrated to enable tailoring of the electronic properties of graphene, with a SiC substrate realising simple resistive devices tuned for extremely sensitive NO2 detection. The gas exposed uppermost layer of the multi layer device is screened from the SiC by the intermediate layers leading to a p-type nature with a higher concentration of charge carriers and therefore, a lower gas response. The single layer graphene device is thought to undergo an n-p transition upon exposure to increasing concentrations of NO2 indicated by a change in response direction. This transition is likely to be due to the transfer of electrons to NO2 making holes the majority carriers. 相似文献
16.
Vinicius Cunha Machado Gladys Tapia David Gabriel Javier Lafuente Juan Antonio Baeza 《Environmental Modelling & Software》2009,24(11):1274-1284
This work proposes a procedure for calibration and validation of complex models by systematically obtaining identifiable parameter subsets according to the available data. The procedure uses the new RDE criteria calculated from the Fisher Information Matrix (FIM) as the ratio of normalized D to modified E criteria (RDE). It does not require expert knowledge and it defines automatically the dimension of the identifiable subset without requiring a threshold for the RDE. It was applied successfully to the study of the IWA-ASM2d model, which was implemented, calibrated and validated for an anaerobic/anoxic/oxic (A2/O) pilot WWTP operated under three different influent ammonium concentrations (15, 20 and 30 mg/L) and two internal recycling ratios (IRR = 2 and 5). Starting from 51 among all the ASM2d parameters, a sensitivity analysis around the ASM2d default values was performed. From the sensitivity ranking, the 20 best-ranked parameters were named “seeds”, since each one served for growing a parameter subset for model calibration. The subset generation process added to the seed a parameter that presented the highest RDE among all the remaining parameters of the sensitivity ranking. The process of parameter addition was repeated until the RDE decreased from the current iteration to the previous one. The best subset determined by the methodology {bPAO, YPO4, μA} presented the highest possible value of the RDE. Finally, the simulation of the WWTP with this subset fitted adequately the experimental data while the parameters obtained had low confidence intervals. 相似文献
17.
A new l-lysine derivative featuring an anthracene unit is synthesized and characterized by elemental analysis, ESI-MS, 1H-NMR, and 13C-NMR. It can selectively bind ATP in acidic aqueous solutions, and be used as a highly selective fluorescent chemosensor for Cu2+ at neutral pH, resulting in fluorescence quenching. According to these characters, two combinational logic circuits are fabricated on a single molecule with three chemical inputs [H+(IN1), OH−(IN2), ATP (IN31)] and [H+(IN1), OH−(IN2), Cu2+(IN32)], respectively. 相似文献
18.
Yangyang ZhangAuthor VitaeWen ShiAuthor Vitae Duan FengAuthor VitaeHuimin MaAuthor Vitae Yan LiangAuthor VitaeJianru ZuoAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):261-265
Exposure to mercury causes severe damage to plants, animals and even humans. Concern over mercury toxicity has encouraged the development of efficient, sensitive, and selective methods for the in vivo detection of mercury. Although a variety of studies have been published describing fluorescence imaging of mercury in animal cells and tissues, no in vivo monitoring has been developed for plant systems until now. In this paper, we report the semi-quantitative fluorescence imaging of Hg2+ ions in a common model plant Arabidopsis thaliana (A. thaliana), with rhodamine B thiolactone (RBS) as a novel Hg2+ probe. The experimental results show that RBS is plant cell wall and cell membrane permeable, and the probe responds selectively to Hg2+ ions instead of the other species in plant systems. Real-time monitoring of Hg2+ absorption in roots of A. thaliana by RBS shows that saturation of Hg2+ uptake could occur in a short period of 3 days at most. The transportation and accumulation of Hg2+ ions in roots of A. thaliana have also been studied, revealing that most of Hg2+ ions reside in root cap and meristematic zone, and only a small amount of Hg2+ ions can reach the maturation zone. This indicates that the interaction of Hg2+ ions with any Hg2+-philic species including proteins in these regions may be responsible for plant poisoning and even death. 相似文献
19.
Yi-Chun Chang Ying-Chia Huang Chih-Ping Chu 《Expert systems with applications》2009,36(10):12423-12440
As Internet use has proliferated, e-learning systems have become increasingly popular. Many researchers have taken a great deal of effort to promote high quality e-learning environments, such as adaptive learning environments, personalized/adaptive guidance mechanisms, and so on. These researches need to collect large amounts of behavioral patterns for the verification and/or experimentation. However, collecting sufficient behavioral patterns usually takes a great deal of time and effort. To solve this problem, this paper proposes a browsing behavior model (B2 model) based on High-Level Petri Nets (HLPNs) to model and generate students’ behavioral patterns. The adopted HLPN contains (1) Colored Petri Nets (CPNs), in which colored tokens can be used to identify and separate student, learning content and assessment, and (2) Timed Petri Nets (TPNs), in which time variable can be used to represent the time at which a student reads learning content. Besides, to validate the viability of the B2 model, this paper implements a B2 modeling tool to generate behavioral patterns. The generated behavioral patterns are compared with actual behavioral patterns collected from elementary school students. The results confirm that the generated behavioral patterns are analogous to actual behavioral patterns. 相似文献
20.
A new poly(vinylchloride) (PVC) membrane electrode for trace level determination of Co2+ ions has been developed based on 5-amino-3-methylisothiazole as an ionophore, o-nitrophenyloctylether as a plasticizer and oleic acid (OA) as a good lipophilic additive. The electrode exhibits a Nernstian slope of 29.5 ± 0.2 mV/decade in a linear range of 1.0 × 10−1 to 6.3 × 10−7 M for Co2+ ions. The detection limit of this electrode is 3.9 × 10−7 M. It has a fast response time of 12 s and can be used for a period of 4 months without any divergence in potentials. The proposed electrode reveals a good selectivity for Co (II) over a wide variety of other tested cations and could be used in the pH range 3.3–9.0. The electrode was successfully applied as an indicator electrode for the potentiometric titration of cobalt ions with EDTA as well as for the direct determination of Co (II) in real samples. 相似文献