共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
Liu TC Zhang HL Wang JH Wang HQ Zhang ZH Hua XF Cao YC Luo QM Zhao YD 《Analytical and bioanalytical chemistry》2008,391(8):2819-2824
Mouse anti-human CD71 monoclonal antibody (anti-CD71) was conjugated with red quantum dots (QDs; 5.3 nm, emission wavelength
λ
em = 614 nm) and used to label HeLa cells successfully. Then green QD-labeled goat anti-mouse immunoglobulin G (IgG; the size
of the green QDs was 2.2 nm; λ
em = 544 nm) was added to bind the red-QD-conjugated anti-CD71 on the cell surface by immunoreactions. Such interaction between
anti-CD71 and IgG lasted 4 min and was observed from the fluorescence spectra: the fluorescence intensity of the “red” peak
at 614 nm increased by 32%; meanwhile that of the “green” one at 544 nm decreased by 55%. The ratio of the fluorescence intensities
(I
544 nm/I
614 nm) decreased from 0.5 to 0.2. The fluorescence spectra as well as cell imaging showed that fluorescence resonance energy transfer
took place between these two kinds of QDs on the HeLa cells through interactions between the primary antibody and the secondary
antibody. 相似文献
3.
Zhen Wei Zheng Liu Rongrong Jiang Chaoqing Bian Tao Huang Aishui Yu 《Journal of Solid State Electrochemistry》2010,14(6):1045-1050
TiO2 array film fabricated by potentiostatic anodization of titanium is characterized by X-ray diffraction (XRD), scanning electron
microscopy (SEM), and charge–discharge measurements. The XRD results indicated that the TiO2 array is amorphous, and after calcination at 500 °C, it has the anatase form. The pore size and wall thickness of TiO2 nanotube arrays synthesized at different anodization voltages are highly dependent on the applied voltage. The electrochemical
performance of the prepared TiO2 nanotube array as an electrode material for lithium batteries was evaluated by galvanostatic charge–discharge measurement.
The sample prepared at 20 V shows good cyclability but low discharge capacity of 180 mA h cm−3, while the sample prepared at 80 V has the highest discharge capacity of 340 mA h cm−3. 相似文献
4.
Fattori Alberto Peter Laurence M. McCall Keri L. Robertson Neil Marken Frank 《Journal of Solid State Electrochemistry》2010,14(10):1929-1936
The electrochemical and spectroelectrochemical properties of the sensitizer dye Z907 (cis-RuLL'(SCN)2 with L=4,4′-dicarboxylic acid-2,2′-bipyridine and L'=4,4′-dinonyl-2,2′-bipyridine) adsorbed on fluorine-doped tin oxide (FTO) and TiO2 surfaces have been investigated. Langmuirian binding constants for FTO and TiO2 are estimated to be 3 × 106 M−1 and 4 × 104 M−1, respectively. The Ru(III/II) redox process is monitored by voltammetry and by spectroelectrochemistry. For Z907 adsorbed
onto FTO, a slow EC-type electrochemical reaction is observed with a chemical rate constant of ca. k = 10−2 s−1 leading to Z907 dye degradation of a fraction of the FTO-adsorbed dye. The Z907 adsorption conditions affect the degradation
process. No significant degradation was observed for TiO2-adsorbed dye. Degradation of the Z907 dye affects the electron hopping conduction at the FTO–TiO2 interface. 相似文献
5.
First results on Fe solid-phase extraction from coastal seawater using anatase TiO2 nano-particles 总被引:1,自引:0,他引:1
Christophe R. Quétel Emilia Vassileva Ivan Petrov Kristina Chakarova Konstantin I. Hadjiivanov 《Analytical and bioanalytical chemistry》2010,396(6):2349-2361
This paper describes the application of TiO2 nano-particles (anatase form) for the solid-phase extraction of iron from coastal seawater samples. We investigated the adsorption
processes by infra-red spectroscopy. We compared in batch and on-(mini)column extraction approaches (0.1 and 0.05 g TiO2 per sample, respectively), combined to external calibration and detection by inductively coupled plasma mass spectrometry
at medium mass resolution. Globally, this titania phase was slightly more efficient with seawater than with ultra-pure water,
although between pH 2 and pH 7, the Fe retention efficiency progressed more in ultra-pure water than in seawater (6.9 versus
4.8 times improvement). Different reaction schemes are proposed between Fe(III) species and the two main categories of titania
sites at pH 2 (adsorption of [FeL
x
](3 − x)+ via possibly the mediation of chlorides) and at pH 7 (adsorption of [Fe(OH)2]+ and precipitation of [Fe(OH)3]0). Under optimised conditions, the inlet system was pre-cleaned by pumping 6% HCl for ∼2 h, and the column was conditioned
by aspirating ultra-pure water (1.7 g min−1) and 0.05% ammonia (0.6 g min−1) for 1 min. Then 3 g seawater sample was loaded at the same flow rate while being mixed on-line with 0.05% ammonia at 0.6 g
min−1 to adjust the pH to 7. The iron retained on the oxide powder was then eluted with 3 g 6% HCl (<0.002% residual salinity in
the separated samples). The overall procedural blank was 220 ± 46 (2 s, n = 16) ng Fe kg−1 (the titania was renewed in the column every 20 samples, with 2-min rinsing in between samples with 6% HCl at 1.5 g min−1). The recovery estimated from the Canadian certified reference material CASS-2 was 69.5 ± 7.6% (2 s, n = 4). Typically, the relative combined uncertainty (k = 2) estimated for the measurement of ∼1 μg Fe kg−1 (0.45 μm filtered and acidified to pH 1.5) of seawater was ∼12%. We applied our method to a similar sample, from the coastal
region of the North Sea. The agreement well within stated uncertainties of our result with the value obtained independently
by isotope dilution mass spectrometry further validated our method. 相似文献
6.
Joint results of the differential scanning calorimetry (DSC) and thermogravimetry (TG) experiments were the basis for the
fusion enthalpy and temperature determination of the biuret (NH2CO)2NH (synthesis by-product of the urea fertilizer (NH2)2CO). Recommended values are Δm
H = (26.1 ± 0.5) kJ mol−1, T
m = (473.8 ± 0.4) K. The DSC method allowed for the phase diagrams of “water–biuret,” “water–urea,” “urea–biuret” binary systems
to be studied; as a result, liquidus and solidus curves were precisely defined. Stoichiometry and decomposition temperature
of the biuret hydrate identified, composition of the compound in “urea–biuret” system was suggested. 相似文献
7.
Petr Kluson Hana Luskova Libor Cerveny Tomas Cajthaml 《Reaction Kinetics and Catalysis Letters》2005,86(2):281-289
Summary Unexpected photocatalytic properties of templated precursors of nanostructured TiO2(titania) were observed in the development of a generally applicable method for the synthesis of a truly nanocrystalline titania
at temperatures compatible with plastic catalytic supports. It specifically comprised the “self-activation”feature of the
TiO2nanostructured precursor (produced within the non-ionic surfactant template) likely induced by the preparation method “imprinted”photoactivity.
Such behavior complied with the principal aim to develop the photocatalytic material without recourse to any significant thermal
step. 相似文献
8.
Sitek B Sipos B Pfeiffer K Grzendowski M Poschmann G Hawranke E Köper K Klöppel G Meyer HE Stühler K 《Analytical and bioanalytical chemistry》2008,391(1):361-365
Large-gel two-dimensional gel electrophoresis (2-DE) is the method of choice for high-resolution proteome analysis of complex
protein mixtures. Until now, however, the advantages of large 2-DE in combination with multiplexed fluorescence dye protein
labelling has been complicated by the separate handling and analysis of the second-dimension gels. Therefore, we adapted the
large 2-DE procedure allowing us to run “one-piece” large 2-DE gels (40 cm × 30 cm) in the second dimension for high resolution
proteome analysis. Here, we show that in combination with fluorescence dye protein saturation labelling “one-piece” large
2-DE enables analysis of small amounts of sample (3 μg protein) for high-resolution proteome analysis. 相似文献
9.
Shuhu Xiao Jiuhui Qu Huijuan Liu Xu Zhao Dongjin Wan 《Journal of Solid State Electrochemistry》2009,13(12):1959-1964
Titanium oxide nanotube electrodes were successfully prepared by anodic oxidation on pure Ti sheets in 0.5 wt.% NH4F + 1 wt.% (NH4)2SO4 + 90 wt.% glycerol mixed solutions. Nanotubes with diameter 40–60 nm and length 7.4 μm were observed by field emission scanning
electron microscope. The electrochemical and photoelectrochemical characteristics of TiO2 nanotube electrode were investigated using linear polarization and electrochemical impedance spectroscopy techniques. The
open-circuit potential dropped markedly under irradiation and with the increase of Cl− concentrations. A saturated photocurrent of approximately 1.3 mA cm−2 was observed under 10-W low-mercury lamp irradiation in 0.1 M NaCl solution, which was much higher than film electrode. Meanwhile,
the highest photocurrent in NaCl solution implied that the photogenerated holes preferred to combine with Cl−. Thus, a significant synergetic effect on active chlorine production was observed in photoelectrocatalytic processes. Furthermore,
the generation efficiency for active chlorine was about two times that using TiO2/Ti film electrode by sol–gel method. Finally, the effects of initial pH and Cl− concentration were also discussed. 相似文献
10.
Nika Veronovski Patrizia Andreozzi Camillo La Mesa Majda Sfiligoj-Smole Volker Ribitsch 《Colloid and polymer science》2010,288(4):387-394
Photocatalytically active TiO2 P25 nanoparticles, widely used for practical applications, were investigated. The nominal size of TiO2 P25 nanoparticles is 21 nm, but they easily agglomerate in aqueous media, depending on pH and ionic strength. TiO2 P25 aqueous dispersions were stabilized by alkanediyl-α,ω-bis-N-dodecyl-N, N′-dimethyl-ammonium bromide, cationic Gemini surfactant. The optimal conditions required to obtain stable dispersions, without
formation of large agglomerates, were experienced. The stabilization of TiO2 P25 nanoparticles by cationic Gemini surfactant was investigated in some details. Different amounts of Gemini surfactant
were used, at concentrations between 1.0 and 250 × 10−6 mol L−1, well below the critical micelle concentration. Dynamic light scattering and zeta potential analyses estimated the particle
size and the dispersions stability. When the proper amount of Gemini surfactant was used, the resulting nanoparticles were
still poly-disperse, but large agglomerates disappeared and were remarkably redispersible. 相似文献
11.
Horst Fr. Schröder Wilhelm Gebhardt Mario Thevis 《Analytical and bioanalytical chemistry》2010,398(3):1207-1229
Municipal wastewater has been examined for steroids, β2-agonists, stimulants, diuretics, and phosphodiesterase type V inhibitors (PDE type V inhibitors), which are “dual-use-drugs”
applied either as anabolic, doping, and lifestyle drugs or for treatment of diverse diseases. To identify their origin, fitness
centre discharges under suspicion of being point sources and sewage-treatment plant feed and effluents were sampled and concentrations
determined. Sensitive and selective methods for determination and quantification based on solid-phase extraction (SPE) followed
by high-performance liquid chromatography–high resolution mass and tandem mass spectrometry (HPLC–(HR)MS and HPLC–MS–MS) were
developed and established for analysis of these compounds in wastewater and to assess their effect on the environment. The
methods developed enabled quantification at trace concentrations (limit of quantification (LOQ): 5 ng L−1). Of the steroids and stimulants under investigation, testosterone, methyltestosterone, and boldenone or ephedrine, amphetamine,
and MDMA (3,4-methylendioxy-N-methylamphetamine) were observed at up to 5 μg L−1 (ephedrine). Of the β2-agonists salbutamol only, and of the diuretics furosemide and hydrochlorothiazide were confirmed in the extracts. Quite high
concentrations of the PDE type V inhibitors sildenafil, tadalafil, and vardenafil and their metabolites were confirmed in
fitness centre discharges (sildenafil: 1,945 ng L−1) whereas their concentrations in municipal wastewater did not exceed 35 ng L−1. This study identified anabolic and doping drugs in wastewater for the first time. Results obtained from wastewater treatment
plant effluents proved that these “dual-use-drugs”, with the exception of hydrochlorothiazide, were mostly eliminated. 相似文献
12.
Zafar MN Beden N Leech D Sygmund C Ludwig R Gorton L 《Analytical and bioanalytical chemistry》2012,402(6):2069-2077
In this study, different flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenases (FADGDHs) were characterized electrochemically
after “wiring” them with an osmium redox polymer [Os(4,4′-dimethyl-2,2′-bipyridine)2(PVI)10Cl]+ on graphite electrodes. One tested FADGDH was that recently discovered in Glomerella cingulata (GcGDH), another was the recombinant form expressed in Pichia pastoris (rGcGDH), and the third was a commercially available glycosylated enzyme from Aspergillus sp. (AspGDH). The performance of the Os-polymer “wired” GDHs on graphite electrodes was tested with glucose as the substrate. Optimal
operational conditions and analytical characteristics like sensitivity, linear ranges and current density of the different
FADGDHs were determined. The performance of all three types of FADGDHs was studied at physiological conditions (pH 7.4). The
current densities measured at a 20 mM glucose concentration were 494 ± 17, 370 ± 24, and 389 ± 19 μA cm−2 for GcGDH, rGcGDH, and AspGDH, respectively. The sensitivities towards glucose were 2.16, 1.90, and 1.42 μA mM−1 for GcGDH, rGcGDH, and AspGDH, respectively. Additionally, deglycosylated rGcGDH (dgrGcGDH) was investigated to see whether the reduced glycosylation would have an effect, e.g., a higher current density, which
was indeed found. GcGDH/Os-polymer modified electrodes were also used and investigated for their selectivity for a number of different sugars. 相似文献
13.
Barthen N Millon E Aubriet F 《Journal of the American Society for Mass Spectrometry》2011,22(3):508-519
Laser ablation of titanium oxides at 355 nm and ion–molecule reactions between [(TiO2)x]–• cluster anions and H2O or O2 were investigated by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with an external ion source.
The detected anions correspond to [(TiO2)x(H2O)yOH]– and [(TiO2)x(H2O)yO2]–• oxy-hydroxide species with x = 1 to 25 and y = 1, 2, or 3 and were formed by a two step process: (1) laser ablation, which
leads to the formation of [(TiO2)x]–• cluster anions as was previously reported, and (2) ion–molecule reactions during ion storage. Reactions of some [(TiO2)x]–• cluster anions with water and dioxygen conducted in the FTICR cell confirm this assessment. Tandem mass spectrometry experiments
were also performed in sustained off-resonance irradiation collision-induced dissociation (SORI-CID) mode. Three fragmentation
pathways were observed: (1) elimination of water molecules, (2) O2 loss for radical anions, and (3) fission of the cluster. Density functional theory (DFT) calculations were performed to explain
the experimental data. 相似文献
14.
Marina E. Rincón Cecilia Cuevas-Arteaga Mauricio Solís de la Fuente Arturo Estrada-Vargas Norberto Casillas Maximiliano Bárcena-Soto 《Journal of Solid State Electrochemistry》2012,16(3):977-983
This paper presents the characterization of TiO2 nanostructures obtained by low-voltage anodization using alternate current electrochemical microscopy (AC-SECM) and photoelectrochemical
(PEC) measurements. TiO2 nanostructures were obtained from the exposure of titanium foils to several aqueous acidic solutions of hydrofluoric acid + phosphoric
acid at potentials of 1 to 3 V. Scanning electron microscopy, X ray diffraction, and atomic force microscopy studies evidence
the formation of a thin porous amorphous layer (<600 nm) with pore size in the range of 200–1,000 nm. By AC-SECM studies at
different bias, we were able to confirm the unambiguous semiconducting properties of as-obtained porous titania films, as
well as differences in surface roughness and conductivity in specimens obtained at both potentials. The difference in conductivity
persists in air annealed samples, as demonstrated by electrochemical impedance spectroscopy and PEC measurements. Specimens
obtained at 3 V show lower photocurrent and dark current than those obtained at 1 V, regardless of their larger conductivity,
and we proposed it is due to differences on the oxide layer formed at the pore bottom. 相似文献
15.
Cai Jin-Hua Ye Yuan-Jian Huang Jin-Wang Yu Han-Cheng Ji Liang-Nian 《Journal of Sol-Gel Science and Technology》2012,62(3):432-440
Three types of silica gel supported titanium dioxide particles immobilizing Zn(II) carboxylphenyl porphyrins appending p-CH3, p-H and p-Cl phenyl substituents (designated as ZnMP–TiO2–SiO2, ZnPP–TiO2–SiO2 and ZnCP–TiO2–SiO2, respectively) have been synthesized and characterized using SEM, XRD, IR, AFS, DRS, UV–Vis, XPS and TG. The photodegradation
of α-terpinene in aqueous suspension was used to determine the photocatalytic activity of TiO2–SiO2 samples which had been impregnated with Zn(II) porphyrins, as sensitizers. The experimental results confirmed that the photocatalytic
activitys of these composites are much higher than those of the nonmodified TiO2–SiO2 under visible light irradiation and follow the order of ZnMP–TiO2–SiO2 > ZnPP–TiO2–SiO2 > ZnCP–TiO2–SiO2. 相似文献
16.
The structure of water solubilized by reverse aggregates of calcium bis(2-ethylhexyl) sulfosuccinate in deuterobenzene and
toluene has been probed by Fourier transform-IR and 1H NMR spectroscopies. The νOD band of solubilized HOD (4% D2O in H2O) has been recorded as a function of the [water]/[surfactant] molar ratio, W/S. Curve fitting of this band showed the presence
of a main peak at 2550 ± 13 cm−1 and a small one at 2405 ± 15 cm−1. As a function of increasing W/S, the frequency of the main peak decreases, its full width at half-height increases, and
its area increases linearly. The 1H NMR chemical shift of solubilized H2O–D2O mixtures at W/S = 18.1 has been measured as a function of the deuterium content of the aqueous nanodroplet. These data were
used to calculate the so-called “fractionation factor” of the aggregate-solubilized water, the value of which was found to
be unity. The results of both techniques show that reverse aggregate-solubilized water, although different from bulk water,
does not seem to coexist in “layers” of different degrees of structure, as suggested, for example by the two-state water-solubilization
model.
Received: 12 July 1999/Accepted: 30 August 1999 相似文献
17.
H. Malankar S. S. Umare K. Singh M. Sharma 《Journal of Solid State Electrochemistry》2010,14(1):71-82
γ-MnO2, synthesized chemically from local manganese ore, was subjected to physicochemical studies. X-ray diffraction, Fourier transform
infrared spectroscopy, surface area measurement, thermogravimetry/differential thermal analysis, scanning electron microscopy,
and chemical analyses were used to determine the structural and chemical disorder present in the samples. The electrochemical
activity in alkaline medium was evaluated by recording discharge profile at constant current and constant load condition.
The charge–discharge profile in 9 M KOH was studied by cyclic voltammetry. The samples were found to be “type III” γ-MnO2 with high degree of microtwinning defect (T
w). The De Wolff disorder was in the range 0.21 < P
r < 0.32. Thermal studies showed weight loss due to the loss of structural water and formation of lower manganese oxides. Mn4+ vacancy, calculated on the basis of cation vacancy model, was in range 0.06 < x < 0.1. The discharge in alkaline medium was accompanied by homogeneous solid-state proton diffusion in MnO2 lattice. The energy density is explained as a function of proton transfer rate (P
t) during the discharge. 相似文献
18.
Rika M. Y. A. Rahman M. M. Salleh A. A. Umar A. Ahmad 《Journal of Solid State Electrochemistry》2010,14(11):2089-2093
A nanoparticle TiO2 solid-state photoelectrochemical cell has been fabricated. The effect of ionic conductivity of a solid electrolyte of polyacrylonitrile
(PAN)–propylene carbonate (PC)–lithium perchlorate (LiClO4) on the performance of a photoelectrochemical cell of indium tin oxide (ITO)/TiO2/PAN–PC–LiClO4/graphite has been investigated. A nanoparticle TiO2 film was deposited onto ITO-covered glass substrate by controlled hydrolysis technique. A solid electrolyte of PAN–LiClO4 with PC plasticizer prepared by solution casting technique was used as a redox couple medium. The room temperature conductivity
of the electrolyte was determined by AC impedance spectroscopy technique. A graphite electrode was prepared onto a glass slide
by electron beam evaporation technique. The device shows a photovoltaic effect under illumination. The short-circuit current
density, J
sc, and open-circuit voltage, V
oc, vary with the conductivity of the electrolyte. The highest J
sc of 2.82 μA cm−2 and V
oc of 0.56 V were obtained at the conductivity of 4.2 × 10−4 Scm−1 and at the intensity of 100 mW cm−2. 相似文献
19.
Ewa Bobrowska-Grzesik 《Mikrochimica acta》2001,136(1-2):31-34
Derivative spectrophotometry was applied for the simultaneous determination of amoxycillin and clavulanic acid in pharmaceutical
preparations: “Augmentin” inj. and tablets and “Amoksiklav” drops and tablets, in solutions after hydrolysis with sodium hydroxide.
As the absorption spectra overlap strongly (amoxycillin λmax = 247 nm and 290 nm, clavulanic acid λmax = 258 nm) the first and the second derivative spectrophotometric procedure was elaborated for their determination. Amoxycillin
was determined at λ = 257.9 nm (1-st derivative spectra) or λ = 273 nm (2-nd derivative) while clavulanic acid at λ = 280.3 nm
(1-st derivative) or λ = 285 nm (2-nd derivative spectra). The Beer’s law is obeyed in the range of 0.004–0.04 mg/ml for amoxycillin
and 0.002–0.02 mg/ml for clavulanic acid.
Received December 6, 1999. Revision August 1, 2000. 相似文献
20.
B. Das M. V. Reddy G. V. Subba Rao B. V. R. Chowdari 《Journal of Solid State Electrochemistry》2011,15(2):259-268
Nano-composites of SnO(V2O3)
x
(x = 0, 0.25, and 0.5) and SnO(VO)0.5 are prepared from SnO and V2O3/VO by high-energy ball milling (HEB) and are characterized by X-ray diffraction (XRD), scanning electron microscopy, and
high-resolution transmission electron microscopy techniques. Interestingly, SnO and SnO(VO)0.5 are unstable to HEB and disproportionate to Sn and SnO2, whereas HEB of SnO(V2O3)
x
gives rise to SnO2.VO
x
. Galvanostatic cycling of the phases is carried out at 60 mA g−1 (0.12 C) in the voltage range 0.005–0.8 V vs. Li. The nano-SnO(V2O3)0.5 showed a first-charge capacity of 435 (±5) mAh g−1 which stabilized to 380 (±5) mAh g−1 with no noticeable fading in the range of 10–60 cycles. Under similar cycling conditions, nano-SnO (x = 0), nano-SnO(V2O3)0.25, and nano-SnO(VO)0.5 showed initial reversible capacities between 630 and 390 (±5) mAh g−1. Between 10 and 50 cycles, nano-SnO showed a capacity fade as high as 59%, whereas the above two VO
x
-containing composites showed capacity fade ranging from 10% to 28%. In all the nano-composites, the average discharge potential
is 0.2–0.3 V and average charge potential is 0.5–0.6 V vs. Li, and the coulombic efficiency is 96–98% after 10 cycles. The
observed galvanostatic cycling, cyclic voltammetry, and ex situ XRD data are interpreted in terms of the alloying–de-alloying
reaction of Sn in the nano-composite “Sn-VO
x
-Li2O” with VO
x
acting as an electronically conducting matrix. 相似文献