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991.
Dr. Samuel Ahoulou Dr. Neus Vilà Dr. Sébastien Pillet Prof. Cédric Carteret Prof. Dominik Schaniel Dr. Alain Walcarius 《Chemphyschem》2021,22(23):2464-2477
Silica matrices hosting transition metal guest complexes may offer remarkable platforms for the development of advanced functional devices. We report here the elaboration of ordered and vertically oriented mesoporous silica thin films containing covalently attached tris(bipyridine)iron derivatives using a combination of electrochemically assisted self-assembly (EASA) method and Huisgen cycloaddition reaction. Such a versatile approach is primarily used to bind nitrogen-based chelating ligands such as (4-[(2-propyn-1-yloxy)]4’-methyl-2,2’-bypiridine, bpy’) inside the nanochannels. Further derivatization of the bpy’-functionalized silica thin films is then achieved via a subsequent in-situ complexation step to generate [Fe(bpy)2(bpy’)]2+ inside the mesopore channels. After giving spectroscopic evidences for the presence of such complexes in the functionalized film, electrochemistry is used to transform the confined diamagnetic (S=0) species to paramagnetic (S=1/2) oxidized species in a reversible way, while blue light irradiation (λ=470 nm) enables populating the short-lived paramagnetic (S=2) excited state. [Fe(bpy)2(bpy’)]2+-functionalized ordered films are therefore both electro- and photo-active through the manipulation of the oxidation state and spin state of the confined complexes, paving the way for their integration in optoelectronic devices. 相似文献
992.
Capillary columns offer the toxicologist several advantages over packed columns. We have presented a highly reproducible screening procedure based on the retention index system and have shown the use of capillary columns for routine quantitation. We are currently expanding the use of these columns in our laboratory and predict that they will be in routine use by most toxicologists in the near future. 相似文献
993.
Walter Jennings 《Journal of separation science》1980,3(12):601-608
Fused silica is an evolutionary product of continuing efforts to improve our chromatographic capabilities. It offers the normal user new horizons in inertness, chromatographic reproducibility, ease of column installation, and possibilities in on-column trapping. Since this writing, chemically bonded phases in several film thicknesses became available on fused silica columns, and these are especially well suited to on-column injections. The use of fused silica syringe needles to inject directly onto fused silica columns seems particularly interesting. Evolution is, of course, a continuous process and it would appear that we can expect continuing developments in this exciting area. 相似文献
994.
Jacek Goworek Andrzej Dąbrowski Mieczysław Jaroniec Jerzy Garbacz 《Monatshefte für Chemie / Chemical Monthly》1982,113(8-9):925-932
The adsorption isotherms of methyl, ethyl,n-propyl andn-butyl acetates from benzene andn-heptane on silica gel have been measured at 298 K. A bilayer model of surface phase has been used to interpret these experimental data. It has been shown that the chain length of the hydrocarbon part of the ester and the solvent affinity to the adsorbent influence the structure of the surface phase. Moreover, this structure is also determined by energetic heterogeneity of the adsorbent surface.
Die Anwendung eines Zweischicht-Adsorptionsmodells zum Verständnis der Adsorption von Estern ausn-Heptan- und Benzollösungen auf Kieselgel
Zusammenfassung Es wurden die Adsorptionsisothermen der Methyl-, Ethyl-,n-Propyl undn-Butylacetate in Benzol undn-Heptanlösungen auf Kieselgel bei 298 K gemessen. Zur Interpretation der experimentellen Daten ist ein Zweischicht-Modell für die Oberflächenphase benutzt worden. Es wurde gezeigt, daß die Länge der Esterkohlenwasserstoffkette und die Aktivität des Lösungsmittels Einfluß auf die Struktur der Oberflächenform haben. Außerdem ist diese Struktur durch energetische Inhomogenität der Adsorbensoberfläche bestimmt.相似文献
995.
Yinqiu Zhen Sheng-e Wang Wenxiang Xiao Hongyan Yuan Dan Xiao 《Mikrochimica acta》2007,159(3-4):305-310
Based on the Nash reagent embedded in silica gel beads as a recognition element, a fluorescent dosimeter for formaldehyde
determination is established. The system can act as a fluorescent off–on switch for the qualitative detection of formaldehyde.
The fluorescence emission of the Nash reagent-loaded silica gel beads is “switches off” (or very low) before exposure to formaldehyde,
while fluorescence can be switched on when the beads are contacted with formaldehyde. The slope of fluorescence time scan
spectra changes with formaldehyde concentration, which constitutes the basis of quantitative determination of formaldehyde
concentration. The formaldehyde can also be semi-quantitatively measured in a naked-eye-detectable fashion. No response of
this dosimeter to primary alcohols, ketones and other common substances was observed. The dosimeter is sensitive, inexpensive,
a disposable, and simple in operation. 相似文献
996.
Jiancui Chen Huifeng Xue Qiaoyun Chen Yao Lin Dianping Tang Jinwen Zheng 《中国化学快报》2019,30(9):1631-1634
A nanoparticle-based potentiometric immunoassay was designed for the sensitive detection of squamous cell carcinoma antigen (SCCA; cervical carcinoma marker) on a portable pH meter coupling enzyme-labeled hybridization chain reaction (HCR) with two alternating hairpin DNA probes for the signal amplification. Initially, a sandwich-type immunoreaction was carried out between anti-SCCA capture antibody-conjugated magnetic bead and detection antibody/initiator strand-coated gold nanoparticle (AuNP). Then, the HCR reaction was readily executed between two glucose oxidase (GOx)-labeled hairpins through the initiator strand to form numerous GOx concatamers on the AuNP via the long nicked double-helix. The concatenated GOx oxidized glucose into gluconic acid and hydrogen peroxide, thus resulting in the pH change of the detection solution on a handheld pH meter. Several labeling protocols including GOx-antibody, GOx-AuNP-antibody and GOx-HCR-AuNP-antibody were investigated for detection of target SCCA, and improved analytical features were obtained with the immune-HCR assay. Under optimum conditions, the immune-HCR assay exhibited good pH responses for the determination of SCCA at a concentration as low as 5.7 pg/mL. Additionally, the immune-HCR assay had good precision and reproducibility, high specificity, and acceptable accuracy for analyzing human serum specimens. 相似文献
997.
将两种N-乙酸取代氮氧杂大环固载(键合)于硅胶上,制得了硅胶固载大环(SGBMC)。研究了它们与Co(Ⅱ),Ni(Ⅱ),C(Ⅱ),Zn(Ⅱ)的配位性能,容量、选择性以及SGBMC的再生。结果表明它们对Cu(Ⅱ)有良好的配位选择性,且配位后的金属离子易为稀盐酸洗脱,SGBMC至少可重复使用5次。 相似文献
998.
A significant effect of pore size has been found on the yield of photolysis of water to hydrogen, ozone (oxidising product) and methane (decomposing product of catalyst or solvent) using [pol-Ti(OBu)4 + CH3OH]-complex/SiO2. The pore structure of silica gel has been found to provide good conditions for forming this type of catalyst. 相似文献
999.
Detection of metal ions by glass capillary gas-chromatographic separation of their volatile chelates
The utility of several glass capillary columns to separate some trifluoroacetonates, diethyldithiocarbamates, di(trifluoroethyl) dilithiocarbamates and diisopropyldithiophosphates metal chelates was investigated. The increased sensitivity offered by selective detectors was also explored. Most favorable results were obtained with a short highly inert fused silica column, coated with a non-retentive liquid phase. 相似文献
1000.
R. C. M. de Nijs 《Journal of separation science》1981,4(12):612-615
A method is described for the preparation of a Porous Layer Open Tubular (PLOT) fused silica column coated with submicron particles of aluminum oxide for the analysis of light hydrocarbons. The column is thermally stable and provides reproducible analytical data over a long period of time. The column can be operated at temperatures easily controlled by commercially available gas chromatographic apparatus. 1,3-Butadiene is retarded much more than its principal impurities: thus the polarity of aluminum oxide is extremely useful for butadiene analysis because none of the contaminants is obscured by the butadiene peak. The analysis of the 16 most common C1–C4 hydrocarbons is achieved within 5 min at 60°C with helium as the carrier gas. Conditioning of the carrier gas with water vapor from CuSO4.5H2O to decrease the activity of the aluminum oxide is described. Some applications of a 30 m × 0.32 mm aluminum oxide PLOT column are given. 相似文献