Consulta: subjectFacets:"Determination"
Registros recuperados: 9
Data/hora: 07/06/2024 09:36:00

The determination of total dissolved free primary amines in seawater: Critical factors, optimized procedure and artefact correction
Provedor de dados: 5
Autores: Aminot, Alain; Kerouel, Roger.
The paper reviews the methods described in the literature for the determination of total dissolved free primary amines (TDFPA) by fluorescence. A wide set of reaction conditions can be found, but they rely on few experiments for their validation. Among fluorogenic compounds, o-plithaldialdehyde (OPA) is more sensitive than fluorescamine and was thus examined here. However, the use of mercaptoethanol (ME) in the reaction (as ail additional derivatization compound) is able to generate unreliable results, in particular when standardization relies on glycine. We suggest replacing ME with 3-mercaptopropionic acid (MPA) which induces more stable and comparable fluorescence among amine Compounds. A systematic study was therefore undertaken to define reagent...
Tipo: Text
Palavras-chave: Fluorescence; Determination; Seawater; Total dissolved free primary amines.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2274.pdf

A flow injection-fluorometric method for the determination of ammonium in fresh and saline waters with a view to in situ analyses
Provedor de dados: 5
Autores: Aminot, Alain; Kerouel, Roger; Birot, Dominique.
A version of the orthophthaldialdehyde-fluorescence ammonium determination for flow injection analysis (FIA) is presented here, with a view to its use for in situ, low-power consumption systems, Thus, the reaction temperature was limited to 30 degreesC and FIA was used in stop-Bow mode (3 min stop). The calibration is linear up to 50 mu mol l(-1), but concentrations up to 100 mu mol l(-1) can be measured. Repeatability is around 1% in the range of 0.5-4 mu mol l(-1) and the detection limit is about 0.03 mu mol l(-1) Over the salinity range of 5-35 (seawater practical salinity scale) the salt effect is almost negligible (within +/- 2%); and below salinity of 5 it increases to a maximum of -9% in fresh water compared to seawater. Hydrogen carbonate,...
Tipo: Text
Palavras-chave: In situ; Fluorometry; Flow injection analysis; Determination; Ammonium.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/publication-1722.pdf

Génétique des huîtres
Provedor de dados: 5
Autores: Gras, Marie-paule; Gras, Paul.
Following the high mortality which killed the Portuguese oysters Crassostrea angulata cultivated on the French coasts, the massive establishment of Pacific oysters Crassostrea gigas, resisting the disease and the creation of artificial deposits for the latter was decided. In most culture areas, the mortality was estimated at more than 80 % of the stock, but, in some regions, some small populations of Crassostrea angulata subsisted and kept on reproducing. A genetic control of the spawner stocks had to be made. The first step was to know if the oysters living in the same areas were of the same species in order to foresee the next generations and try to improve them (selection).
Tipo: Text
Palavras-chave: Sélection; Determination; Crassostrea gigas; Crassostea angulata; Huîtres; Génétique.
Ano: 1977
URL: http://archimer.ifremer.fr/doc/1977/acte-6579.pdf

Méthode de dosage du cadmium, du cuivre, du plomb et du zinc dans la chair de poissons
Provedor de dados: 5
Autores: Auger, Dominique.
An analytical technique for cadmium, copper, lead and zinc determination in fish tissue used in monitoring programmes is described. Atomic absorption spectrophotometry on nitric digested samples is performed.
Tipo: Text
Palavras-chave: Cadmium; Cuivre; Poisson; Plomb; Zinc; Analyse; Cadmium; Copper; Lead; Zinc; Fish; Determination.
Ano: 1989
URL: https://archimer.ifremer.fr/doc/00489/60059/63343.pdf

A re-examination of matrix effects in the segmented-flow analysis of nutrients in sea and estuarine water
Provedor de dados: 5
Autores: Coverly, Stephen; Kerouel, Roger; Aminot, Alain.
Modern instruments together with the use of standard reference materials have improved the accuracy and long-term reproducibility of the analysis of nutrients (ammonium, nitrate, nitrite, phosphate and silicate) in sea water using segmented-flow analysis, so that errors arising from matrix effects become more significant. Colorimetric detectors with bubble-through flowcells have become widely used for seawater analysis in recent years and their associated matrix effects are described. A re-examination of all categories of matrix effects, whose main origin is salinity, was thus undertaken to assess how much they are liable to alter the data. Interferences were classified into four types, each of which was examined in order to show its influence on the...
Tipo: Text
Palavras-chave: Nutrient; Determination; Seawater; Estuarine water; Segmented-flow analysis; Matrix effects.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00057/16843/14530.pdf

Easier detection of invertebrate "identification-key characters" with light of different wavelengths
Provedor de dados: 5
Autores: Koken, Marcel; Grall, Jacques.
The marine alpha-taxonomist often encounters two problems. Firstly, the "environmental dirt" that is frequently present on the specimens and secondly the difficulty in distinguishing key-features due to the uniform colours which fixed animals often adopt. Here we show that illuminating animals with deep-blue or ultraviolet light instead of the normal white-light abrogates both difficulties; dirt disappears and important details become clearly visible. This light regime has also two other advantages. It allows easy detection of very small, normally invisible, animals (0.1 mu m range). And as these light wavelengths can induce fluorescence, new identification markers may be discovered by this approach.
Tipo: Text
Palavras-chave: Fluorescent colours; Light emission; Determination; Cryptic species; Dimorphism; Pattern UV light; Deep-blue light; Autofluorescence.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00185/29660/28026.pdf

Voltammetric characteristics of miconazole and its cathodic stripping voltammetric determination
Provedor de dados: 42
Autores: PEREIRA,FRANCISCO C.; STRADIOTTO,NELSON R.; ZANONI,MARIA VALNICE B.
Miconazole is reduced at mercury electrode above pH 6 involving organometallic compound formation, responsible for an anomalous polarographic behavior. The electrodic process presents a large contribution of the adsorption effects. The drug can be determined by cathodic stripping voltammetry from 8.0 x 10-8 to 1, 5 x 10-6 molL-1 in Britton-Robinson buffer pH 8.0, when pre-accumulated for 30s at an accumulation potential of 0V. A relative standard deviation of 3.8% was obtained for ten measurements of 1.0 x 10-7 molL-1 miconazole in B-R buffer pH 8.0 and a limit detection of 1, 7 x 10-8 molL-1 was determined using 60s of deposition time and scan rate of 100 mVs-1. The proposed method is simple, precise and it was applied successfully for the determination...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Miconazole; Voltammetry; Electroanalysis; Determination.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000300005

Determination of amylase activity in cotyledons of Phaseolus vulgaris L. cv. carioca
Provedor de dados: 52
Autores: Morais,Glaucia Almeida de; Takaki,Massanori.
Determination of α- and β-amylase activity in the extracts of cotyledons of Phaseolus vulgaris L. cv. cariocawas done using selective inactivation of α-amylase by lowering the pH of the incubation medium or by the use of EDTA as inhibitor or selective inactivation of β-amylase by the use of HgCl2 or by heating to 70ºC in the presence of CaCl2; and still by using the reagent starch azure for specific determination of α-amylase. Results indicated that the methods used were inappropriate in this case, being indicated the determination of total amylase activity.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Α-amylase; Β-amylase; Determination; Selective inactivation; Phaseolus vulgaris.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131998000100003

Detection and characterization of human rotavirus in hospitalized patients in the cities of Ponta Grossa, Londrina and Assai - PR, Brazil
Provedor de dados: 55
Autores: Nozawa,Carlos M; Kerntopf,Gustavo Franthesco; Czernisz,Érika da Silva; Albuquerque,Daniele; Romanin,Priscila; Freitas,José Felipe Eliseu; Santos,Norma; Benati,Fabrício José; Pietruchinski,Eduardo; Linhares,Rosa Elisa Carvalho.
Acute diarrheal disease is still one of the major public health problems worldwide. Rotaviruses (RV) are the most important viral etiologic agents and children under five years of age are the target population. OBJECTIVE: To investigate the rate of RV infection in hospitalized patients due to acute diarrhea in the cities of Ponta Grossa, Londrina and Assai - Paraná. METHODS: Latex agglutination (LA); immunochromatography (ICG); polyacrylamide gel electrophoresis (PAGE) and negative staining electron microscopy (ME) tests were used to detect the virus. For the genotyping, RT-PCR and RT-PCR-ELISA were used, respectively, for NSP4 and VP4/VP7. RESULT: Out of 124 samples there were 69 positive stool samples for RV, for at least one of the used tests, 67 of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Rotavirus; Determination; Hospitalized patients; Genotyping.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702010000600002