State-of-the-art in analytical characterization of high purity solid samples by different spectroscopic methods

AbstractIn this paper we describe synchrotron based, state-of-the-art spectroscopic methods for the analysis of surfaces and interfaces in thin film photovoltaic devices, their merits and their limitations. Using results obtained with the “CISSY” end station at the BESSY synchrotron in Berlin, Germany, we show how surface sensitive Synchrotron excitedX-rayPhotoelectronSpectroscopy(SXPS)andSoftX-rayEmissionSpectroscopy (SXES), which yields compositional and chemical depth information in the ten to hundred nm scale, have increased our knowledge of the chemistry of surfaces and buried interfaces of these systems.

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The isolation, analytical characterization by HPLC-UV and NMR spectroscopy, cytotoxic and antioxidant activities of baeomycesic acid from Thamnolia vermicularis var. subuliformis

Hemijska industrija ◽

10.2298/hemind110414035m ◽

2011 ◽

Vol 65 (5) ◽

pp. 591-598

Author(s):

Nedeljko Manojlovic ◽

Perica Vasiljevic ◽

Dragan Nikolic ◽

Gordana Bogdanovic-Dusanovic ◽

Zoran Markovic ◽

...

Keyword(s):

Antioxidant Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Herbal Medicines ◽

Rapid Identification ◽

Cytotoxic Activities ◽

Spectroscopic Methods ◽

Scavenging Activity ◽

Analytical Characterization

The aim of this work was the analytical characterization of the ?-orcinol depside, baeomycesic acid in lichens extracts. The extract of Thamnolia vermicularis var. subuliformis was analyzed by the two different methods, namely HPLC-UV and 1H NMR analysis. The results showed that baeomycesic acid was the most abundant depside in the lichens. These results could be of use for rapid identification of this metabolite in other lichen species. Besides baeomycesic acid, three depsides and one monocyclic phenolic compound were isolated from the lichen extract on the chromatographic column. The structure of baeomycesic acid was confirmed by HPLC-UV and spectroscopic methods. In addition, antioxidant and cytotoxic activities of baeomycesic acid were determined. The result of the testing showed that baeomycesic acid exhibited a moderate radical scavenging activity (IC50 = 602.10 ? 0.54 ?g/mL) and good cytotoxic activity. This is the first report of detailed analytical characterization, isolation, as well as antioxidant and cytotoxic activities of baeomycesic acid from Thamnolia vermicularis. These results may be helpful in future industrial production of herbal medicines that include this important natural product.

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Recent problems and limitations in the analytical characterization of high-purity material☆

Talanta ◽

10.1016/0039-9140(74)80123-2 ◽

1974 ◽

Vol 21 (5) ◽

pp. 327-345 ◽

Cited By ~ 33

Author(s):

Günther Tölg

Keyword(s):

High Purity ◽

Analytical Characterization ◽

Purity Material

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TEM characterization of WSix films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171973 ◽

1994 ◽

Vol 52 ◽

pp. 848-849

Author(s):

V. C. Kannan ◽

S. M. Merchant ◽

R. B. Irwin ◽

A. K. Nanda ◽

M. Sundahl ◽

...

Keyword(s):

Integrated Circuits ◽

Vapor Deposition ◽

High Purity ◽

Physical Vapor Deposition ◽

Thermal Treatments ◽

Rapid Thermal Anneal ◽

Tungsten Silicide ◽

Tem Characterization ◽

Metal Silicides

Metal silicides such as WSi2, MoSi2, TiSi2, TaSi2 and CoSi2 have received wide attention in recent years for semiconductor applications in integrated circuits. In this study, we describe the microstructures of WSix films deposited on SiO2 (oxide) and polysilicon (poly) surfaces on Si wafers afterdeposition and rapid thermal anneal (RTA) at several temperatures. The stoichiometry of WSix films was confirmed by Rutherford Backscattering Spectroscopy (RBS). A correlation between the observed microstructure and measured sheet resistance of the films was also obtained.WSix films were deposited by physical vapor deposition (PVD) using magnetron sputteringin a Varian 3180. A high purity tungsten silicide target with a Si:W ratio of 2.85 was used. Films deposited on oxide or poly substrates gave rise to a Si:W ratio of 2.65 as observed by RBS. To simulatethe thermal treatments of subsequent processing procedures, wafers with tungsten silicide films were subjected to RTA (AG Associates Heatpulse 4108) in a N2 ambient for 60 seconds at temperatures ranging from 700° to 1000°C.

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