Consulta: subjectFacets:"Elemental composition"
Registros recuperados: 3
Data/hora: 05/06/2024 07:53:29

Elemental composition of individual pico- and nano-sized marine detrital particles in the northwestern Mediterranean Sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mostajir, B; Fagerbakke, Km; Heldal, M; Thingstad, Tf; Rassoulzadegan, F.
The elemental composition of individual &lt; 10 mu m detrital particles from Mediterranean surface waters was analysed using a Transmission Electron Microscope (TEM) equipped with an energy dispersive X-Ray microanalyser. Results show that carbon and phosphorus content per detritus volume are much higher in pico-detrital particles &lt; 2 mu m (42 kg C m(-3) and 1 kg P m(-3)) than in 5-10 mu m detrital particles (20 kg C m-3 and 0.1 kg P m(-3)). The C:N:P atomic ratios for different sized fractions of the detrital particles were found to be 82:10:1 for &lt; 2 mu m particles, 120:29:1 for 2-5 mu m particles and 308:37:1 for 5-10 mu m particles. The average ratio for all size classes of detrital particles (&lt; 10 mu m) was 132:23:1. The differences in...
Tipo: Text
Palavras-chave: Détritus; Composition élémentaire; Microscope électronique à transmission; Rayons X; Méditerranée; Detritus; Elemental composition; TEM; X-ray; Mediterranean.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43661/43208.pdf

CHARACTERIZATION OF BULK SOIL HUMIN AND ITS ALKALINE-SOLUBLE AND ALKALINE-INSOLUBLE FRACTIONS
Provedor de dados: Revista Brasileira de Ciência do Solo
Autores: Li,Cuilan; Gao,Shuqing; Gao,Qiang; Wang,Lichun; Zhang,Jinjing.
Humic substances are the major components of soil organic matter. Among the three humic substance components (humic acid, fulvic acid, and humin), humin is the most insoluble in aqueous solution at any pH value and, in turn, the least understood. Humin has poor solubility mainly because it is tightly bonded to inorganic soil colloids. By breaking the linkage between humin and inorganic soil colloids using inorganic or organic solvents, bulk humin can be partially soluble in alkali, enabling a better understanding of the structure and properties of humin. However, the structural relationship between bulk humin and its alkaline-soluble (AS) and alkaline-insoluble (AIS) fractions is still unknown. In this study, we isolated bulk humin from two soils of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil humic substances; Humin fractionation; Elemental composition; 13C NMR.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000100120

Chemical quality of bottled mineral waters from markets of Curitiba-PR-Brazil
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Santos,Éder José dos; Oliveira Junior,Dasio Roberto de; Hermann,Amanda Beatriz; Sturgeon,Ralph Edward.
ABSTRACT Twenty-seven bottled mineral waters from local markets in Curitiba, State of Paraná, Brazil were analyzed for a number of constituents, including: pH, conductivity, total dissolved solids, hardness, HCO3  - and CO 3  2-, as well as Ca2+, Mg2+, Na+, K+, NH4 + , F-, Cl-, NO3 -, NO2 - and SO4 2- by ion chromatography (IC); Al, Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Sr, V and Zn by inductively coupled plasma optical emission spectrometry (ICP OES); Hg by cold vapor generation-ICP OES and As, Pb, Sb and Se by ICP-mass spectrometry (ICP-MS). The obtained limits of quantitation (LOQ) were adequate for the determination of all analytes using the various analytical techniques. Results for the analysis of AccuStandard certified reference materials QCS-01-5,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bottled mineral waters; Elemental composition; Chemical quality; Principal component analysis.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132016000100513