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Analytical Aspects (analytical + aspect)

Distribution by Scientific Domains
Chemistry66%

Selected Abstracts

Lichen extracts as raw materials in perfumery.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2009
Part 1: oakmoss
Abstract A comprehensive review is presented on extracts of a lichen, oakmoss (Evernia prunastri), that are used in the fragrance industry. Analytical aspects are discussed in detail, from both qualitative and quantitative standpoints, mainly in relation to the industrial processing of the lichen. It is shown that more than 170 constituents have been identified so far in oakmoss extracts, including 47 depsides or depside-derived compounds and 25 triterpenes or steroids. A survey of industrially relevant synthetic products with an oakmoss odour is included. Toxicology issues related to the use of oakmoss extracts in cosmetics and fragrance formulations are critically reviewed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Analytical aspects of pharmaceutical grade chondroitin sulfates

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2007
Nicola Volpi
Abstract Chondroitin sulfate is a very heterogeneous polysaccharide in terms of relative molecular mass, charge density, chemical properties, biological and pharmacological activities. It is actually recommended by EULAR as a symptomatic slow acting drug (SYSADOA) in Europe in the treatment of knee osteoarthritis based on meta-analysis of numerous clinical studies. Chondroitin sulfate is also utilized as a nutraceutical in dietary supplements mainly in the United States. On the other hand, chondroitin sulfate is derived from animal sources by extraction and purification processes. As a consequence, source material, manufacturing processes, the presence of contaminants, and many other factors contribute to the overall biological and pharmacological actions of these agents. The aim of this review is to evaluate new possible more specific analytical approaches to the determination of the origin and purity of chondroitin sulfate preparations for pharmaceutical application and in nutraceuticals, such as the evaluation of the molecular mass values, the constituent disaccharides, and the specific and sensitive agarose-gel electrophoresis technique. Furthermore, a critical evaluation is presented, together with a discussion of the limits of these analytical approaches. Finally, the necessity for reference standards having high specificity, purity and well-known physico-chemical properties useful for accurate and reproducible quantitative analyses will be discussed. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3168,3180, 2007 [source]

Bioanalysis of pentoxifylline and related metabolites in plasma samples through LC-MS/MS

BIOMEDICAL CHROMATOGRAPHY, Issue 6 2010
Daniela Iuliana Sora
Abstract Analytical aspects related to the assay of pentoxifylline (PTX), lisofylline (M1) and carboxypropyl dimethylxanthine (M5) metabolites are discussed through comparison of two alternative analytical methods based on liquid chromatography separation and atmospheric pressure electrospray ionization tandem mass spectrometry detection. One method is based on a ,pure' reversed-phase liquid chromatography mechanism, while the second one uses the additional polar interactions with embedded amide spacers linking octadecyl moieties to the silicagel surface (C-18 Aqua stationary phase). In both cases, elution is isocratic. Both methods are equally selective and allows separation of unknowns (four species associated to PTX, two species associated to M1) detected through specific mass transitions of the parent compounds and owning respective structural confirmation. Plasma concentration,time patterns of these compounds follow typical metabolic profiles. It has been advanced that in-vivo formation of conjugates of PTX and M1 is possible, such compounds being cleaved back to the parent ones within the ion source. The first method was associated with a sample preparation procedure based on plasma protein precipitation by strong organic acid addition. The second method used protein precipitation by addition of a water miscible organic solvent. Both analytical methods were fully validated and used to assess bioequivalence between a prolonged release generic formulation and the reference product, under multidose and single dose approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Lichen extracts as raw materials in perfumery.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2009
Part 2: treemoss
Abstract This is a comprehensive review of extracts from the lichen Pseudevernia furfuracea (treemoss) that are used in the fragrance industry. Qualitative and quantitative analytical aspects are critically reviewed and the results are compared to those of the related oakmoss extracts. It is shown that more than 90 constituents have been identified so far in treemoss extracts, including 42 depsides, depsidones or depside-derived compounds, and 42 triterpenes or steroids. Constituents of certain host trees, mainly Pinus species, generate specific analytical and toxicological issues which need to be considered in addition to those related to the known degradation products of lichen compounds. A new classification of lichen extracts used as raw materials in fragrance compounding is proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Automatic analysis of aqueous specimens for phytoplankton structure recognition and population estimation

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 9 2006
Karsten Rodenacker
Abstract An automatic microscope image acquisition, evaluation, and recognition system was developed for the analysis of Utermöhl plankton chambers in terms of taxonomic algae recognition. The system called PLASA (Plankton Structure Analysis) comprises (1) fully automatic archiving (optical fixation) of aqueous specimens as digital bright field and fluorescence images, (2) phytoplankton analysis and recognition, and (3) training facilities for new taxa. It enables characterization of aqueous specimens by their populations. The system is described in detail with emphasis on image analytical aspects. Plankton chambers are scanned by sizable grids, divers objective(s), and up to four fluorescence spectral bands. Acquisition positions are focused and digitized by a TV camera and archived on disk. The image data sets are evaluated by a large set of quantitative features. Automatic classifications for a number of organisms are developed and embedded in the program. Interactive programs for the design of training sets were additionally implemented. A long-term sampling period of 23 weeks from two ponds at two different locations each was performed to generate a reliable data set for training and testing purposes. These data were used to present this system's results for phytoplankton structure characterization. PLASA represents an automatic system, comprising all steps from specimen processing to algae identification up to species level and quantification. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source]

Tocopheryl quinones and mitochondria

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 5 2010
Lars Gille
Abstract In the past, the role of tocopherols and tocopheryl hydroquinones as antioxidants in mitochondria has been examined. However, structural properties of tocopherols and tocopheryl quinones (arrangement of polar/apolar moieties) have also been recognized as being crucial for the selective transport of RRR-,-congeners compared with other tocopherols in the cell, suggesting that these properties might be generally important for the binding of vitamin E-related compounds to proteins and enzymes in mitochondria. Therefore, direct modulation of mitochondrial activities, such as bioenergetics, production of reactive oxygen species and apoptosis, not exclusively related to the redox activity of these compounds is increasingly studied. This overview focuses on the influence of ,-/,-tocopheryl quinones and their parent ,-/,-tocopherols on mitochondrial functions, including formation of tocopheryl quinones, their analytical aspects, their potential as alternative substrates and their inhibitory activity for some mitochondrial functions. It is shown that the understanding of how tocopheryl quinones and tocopherols interfere with mitochondrial functions on the molecular level is still incomplete and that a better comprehension requires further research activities. [source]