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Quantitative Composition (quantitative + composition)
Selected AbstractsEnantioselective analysis of pheniramine in urine by charged CD-mediated CZE provided with a fiber-based DAD and an on-line sample pretreatment by capillary ITPELECTROPHORESIS, Issue 15 2007Jozef Marák Abstract Application potentialities of CZE on-line coupled with capillary ITP and DAD to the identification and determination of trace concentration levels (,g/L) of pheniramine (PHM) enantiomers and their metabolites present in complex ionic matrices of biological origin (urine) are shown. An enhanced (enantio)selectivity of the CZE separation system obtained by the addition of carboxyethyl-,-CD (CE-,-CD) to the carrier electrolyte provided CZE conditions for a reliable identification of similar/identical DAD spectra of structurally related compounds (PHM enantiomers and their metabolites) in clinical urine samples differing in qualitative and quantitative composition of sample matrix constituents. A high sample loadability (a 30,,L sample injection volume), partial sample clean-up (removing macroconstituents from the sample), and preconcentration of the analytes in ITP stage resulted in the decrease of concentration LOD for PHM enantiomers in urine to 5.2 and 6.8,,g/L (2.2×10,8 and 2.8×10,8,mol/L), without using any sample pretreatment technique. The background correction and smoothing procedure applied to the raw DAD spectra provided analytically relevant DAD spectra of PHM enantiomers and their metabolites also when they were present in urine sample (30,,L injection volumes of ten-times diluted urine sample) at a 9×10,8,mol/L concentration. DAD spectra of PHM enantiomers present in urine samples matched their reference spectra with reasonable certainties. DAD spectra of PHM metabolites were compared with the reference spectra of PHM enantiomers and a good match was found which indicates the similarities in the structures of enantiomers and their metabolites detected in the urine samples. This fact allows performing the quantitative analyses of PHM metabolites in the urine samples by applying the calibration parameters of PHM enantiomers also for PHM metabolites and the results show the possibilities of using the ITP,CZE,DAD combination for the direct analysis of PHM enantiomers and/or their metabolites in urine without any sample pretreatment. ITP,CZE,DAD method with oppositely charged selector is suggested to use in clinical research as it provides favorable performance parameters including sensitivity, linearity, precision, recovery, and robustness with minimal demands on sample preparation. [source] The volatile constituents of frankincense , a reviewFLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2009Michaela Mertens Abstract The smell of frankincense resin and powder, as well as burned frankincense, has been linked to a series of health effects since ancient times. Additionally, frankincense and its fumes are used as a means to induce positive psychophysical effects and well-being, not only in an ecclesiastical setting but also in traditional medical applications. This review aims to provide an overview of current knowledge of the volatile constituents of frankincense, with explicit consideration concerning the diverse Boswellia varieties. Altogether, more than 300 volatiles in frankincense have been reported in the literature. In particular, a broad diversity has been found in the qualitative and quantitative composition of the volatiles with respect to different varieties of Boswellia. A detailed discussion of the various analytical approaches applied to isolating and analysing the volatile fractions of frankincense is also presented. Copyright © 2009 John Wiley & Sons, Ltd. [source] Enantiomeric composition studies in Lavandula species using supercritical fluidsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2005Gema Flores Abstract Characteristic aroma compounds in plants and essential oils of Lavandula from different varieties were examined. The study of the qualitative and quantitative composition of the major volatile components was faced by developing a method based on the use of supercritical fluid extraction-GC-MS (SFE-GC-MS). The optimization of a variety of parameters affecting SFE extraction enabled RSDs from three replicates lower than 2% to be achieved. Equally, recoveries of up to 59% were obtained by applying the proposed method. The use of multidimensional GC was necessary to enantiomerically resolve the target compounds. The obtained results showed enantiomeric purities >90% for all studied compounds in all varieties considered, proving the natural invariability of the enantiomeric composition of the compounds of interest. This information can be useful in authenticity studies as well as in selecting natural sources of enantiomerically pure compounds. [source] Mechano-Synthesis of Lead,Magnesium,Niobate CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2006Danjela Kuscer The synthesis of Pb(Mg1/3Nb2/3)O3 (PMN) with high-energy milling was studied by X-ray powder diffraction (XRD) using the Rietveld-refinement method. The results are discussed in terms of the qualitative and quantitative composition of the crystalline and amorphous phases as a function of milling time. The mechano-synthesis of PbO, Nb2O5, and MgO leads to the formation of perovskite PMN. In the initial stage of milling, particle size reduction and a high degree of amorphization were observed, together with the simultaneous formation of perovskite and pyrochlore-type structures. A mechanism for the formation of PMN by the mechano-synthesis route is proposed. [source] Brassica oleracea var. costata: comparative study on organic acids and biomass production with other cabbage varietiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2009Carla Sousa Abstract BACKGROUND: A study was undertaken to evaluate the effect of agronomic practices, harvesting time and leaf age on the organic acid composition and biomass production of Brassica oleracea L. var. costata DC (tronchuda cabbage). Samples were cultivated under eight different fertilisation regimes (two levels each of nitrogen, boron and sulfur, an organic fertiliser and no fertiliser) and collected at three different times. RESULTS: Principal component analysis of the data indicated significant differences. Three principal components with an eigenvalue higher than one accounted for 79.0% of the total variance of the data set. Samples obtained with conventional fertilisation were characterised by the highest values of fresh weight. External leaves showed higher total organic acid and malic acid contents than internal leaves, while the latter were characterised by higher proportions of citric acid. For consecutive harvests, total organic acid concentration decreased in both external and internal leaves. CONCLUSION: The use of a conventional fertilisation regime (nitrogen, boron or sulfur) improved the growth of B. oleracea var. costata without affecting its organic acid profile. However, for consecutive harvests, total organic acid concentration was observed to decrease independently of the agronomic practices tested. Leaf age influenced the quantitative composition of organic acids. Copyright © 2009 Society of Chemical Industry [source] Essential oil composition and antifungal activity of Foeniculum vulgare Mill. obtained by different distillation conditionsPHYTOTHERAPY RESEARCH, Issue 4 2003N. Mimica-Duki Abstract The in,uence of different hydrodistillation conditions was evaluated from the standpoint of essential oil yield, chemical composition and antifungal activity from seeds of Foeniculum vulgare Mill. Three hydrodistillation conditions were considered. The main constituents of the oils were: (E)-anethole (72.27%,74.18%), fenchone (11.32%,16.35%) and methyl chavicol (3.78%,5.29%). The method of distillation signi,cantly effected the essential oil yield and quantitative composition, although the antifungal activity of the oils against some fungi was only slightly altered. Copyright © 2003 John Wiley & Sons, Ltd. [source] The limit of leucocytospermia from the microbiological viewpointANDROLOGIA, Issue 5 2003Margus Punab Summary. The aim of the study was to find out the correlation between white blood cell (WBC) counts in semen and quantitative composition of seminal microflora, and to establish the minimum WBC count associated with significant bacteriospermia. The research included 159 men with different WBC counts in their semen, 84 of them with chronic prostatitis/chronic pelvic pain syndrome. Semen samples were cultivated quantitatively for detecting anaerobic, microaerophilic and aerobic bacteria. Bryan-Leishman stained slides were used for detecting WBC in semen. Seminal fluid was colonized by eight different microorganisms, and the total count of microorganisms in semen ranged from 102 to 107 CFU ml,1. A high frequency of anaerobic microorganisms was found. A positive correlation was observed between the WBC count and the number of different microorganisms, and also between the WBC count and the total count of microorganisms in semen sample. The receiver operating characteristic curve analysis demonstrated that the WHO-defined WBC cut-off point (1 × 106 WBC ml,1) has very low sensitivity for discriminating between patients with and without significant bacteriospermia, as a more optimal sensitivity/specificity ratio appears at 0.2 × 106 WBC ml,1 of semen. The quantitative microbiological finding of semen in the patients of National Institute of Health (NIH) categories IIIa and IV was very similar, i.e. a high number of different microorganisms and a high total count of microorganisms. In the control group (without leucocytospermia and prostatitis symptoms) both parameters were significantly lower. [source] GC-MS analysis of penta- and tetra-cyclic triterpenes from resins of Pistacia species.BIOMEDICAL CHROMATOGRAPHY, Issue 8 2005Part II. Abstract Pistacia species contain oleoresins with bioactive triterpenes. In this study triterpenes, including minor components, were identified and quantified in both neutral and acidic fractions of Pistacia terebinthus var. Chia resin, grown exclusively in Chios island (Greece), collected traditionally, as well as using stimulating agents (liquid collection). It was proved that these two resin samples were composed of several different minor triterpenes, while major constituents were similar but in different proportions. Compounds that differentiated two resin samples of P. lentiscus and P. terebinthus var. Chia, both traditionally collected, were detected, in order to identify the nature of resins present in archaeological materials. In the traditionally collected resin, 37 triterpenes were identified, 12 in the acidic and 25 in the neutral fraction. In the liquid collection resin 10 compounds were identified in the acidic and 23 in the neutral fraction, while 16 compounds were not contained in the traditionally collected resin. The main triterpenes in both resin samples collected traditionally and using stimulating agents were: isomasticadienonic acid (23.6 and 26.3% w[sol ]w of the triterpenic fraction, respectively), 28-norolean-17-en-3-one (16.3 and 17.5% w[sol ]w of the triterpenic fraction, respectively) and masticadienonic acid (5.8 and 6.0% w[sol ]w of the triterpenic fraction). In this study the qualitative and quantitative composition of triterpenes was compared in the Pistacia lentiscus and P. terebinthus var. Chia resin samples collected with the traditional and new liquid techniques, and also triterpenes in resins of P. terebinthus obtained by the traditional technique and using stimulating agents. The aim of the study was also to examine whether the collection technique influenced the triterpenes contained in P. terebinthus var. Chia resin samples. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sedimentation History of Neogene Lacustrine Sediments of Su,eo,ka Bela Stena Based on Geochemical Parameters (Valjevo-Mionica Basin, Serbia)ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 6 2008AJNOVI, Aleksandra Abstract: Sediments of the western part of the Valjevo-Mionica basin (Serbia) were examined both geochemically and mineralogically to explain, on the basis of their sedimentological characteristics, the causes of changes in their qualitative and quantitative composition. A total of 62 samples obtained from the drillhole at depths up to 400 m was investigated. Using correlation of the obtained data, six geochemical zones were defined, two of which being specially distinguished by their mineralogical, geochemical and sedimentological characteristics. The first one, upper zone A, consists of banded marlstones interbedded with clay and oil shales and is characterized by presence of analcite and searlesite. These minerals and very high contents of Na2O indicate sedimentation in alkaline conditions with increased salinity in arid climate. That provided pronounced water stratification, as well as higher bioproductivity in the basin and sedimentary organic matter preservation. Therefore, the zone A sediments are characterized by high organic matter contents of the type which provides good potential for production of liquid hydrocarbons. Another specific zone, zone F, contains sediments with very high MgO, K2O and Li concentrations. Their geochemical correlation, as well as almost complete absence of illite in this zone, indicates the presence of interstratified clay mineral type illite-saponite (lithium-bearing Mg-smectite). [source] Temporal Variations in Fine Sand Assemblages in the North Aegean Sea (Eastern Mediterranean)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 2 2004Evdokia Kourelea Abstract Two sites were selected in the North Aegean Sea for the study of shallow fine sand assemblages, which are poorly known in the Eastern Mediterranean. The biomonitoring of these sites can provide useful information on the impact of human activities on the macrofaunal and meiofaunal composition of these assemblages. In order to examine this impact, sampling took place in five different periods between 2000 and 2001. The qualitative and quantitative compositions of the communities at the two sites showed certain differences, mostly between the sites and the year of sampling rather than between sampling periods, which would be the expected outcome. The communities seem to be affected by a combination of the human activities with the particular hydrodynamics of the studied sites. [source] | ||||||||||||||||