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A flow injection-fluorometric method for the determination of ammonium in fresh and saline waters with a view to in situ analyses ArchiMer
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
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Exoproteolytic activity determined by flow injection analysis: its potential importance for bacterial growth in coastal marine ponds ArchiMer
Delmas, Daniel; Legrand, Catherine; Bechemin, Christian; Collinot, Cecile.
The measurement of the fluorescent 4-methyl-7-coumarinylamine released from the hydrolysis of a non-fluorescent peptide model substrate by exoproteolytic enzymes has been adapted to flow injection analysis (FIA). FIA allows samples to be processed very quickly (less than 2 min. for triplicate determinations) with good sensitivity (< 0.1 muM) and reproducibility (relative standard deviation < 3 % at the 0.2 muM level). In a coastal marine pond, exoproteolytic activity was closely related to bacterioplankton biomass. The high activity measured in pond water (maximum velocity: V(M) almost-equal-to 1.46 to 2.54 muM.h-1) emphasizes the importance of dissolved protein hydrolysis for bacterial growth and for dissolved organic nitrogen cycling. The mean...
Tipo: Text Palavras-chave: Activité exoprotéolytique; Protéine dissoute; Analyse en flux continu; Bactérioplancton; Marais maritime; Flow injection analysis; Exoproteolytic activity; Dissolved protein; Bacterioplankton; Coastal marine pond.
Ano: 1994 URL: http://archimer.ifremer.fr/doc/00196/30756/29163.pdf
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Impact of environmental factors on in situ determination of iron in seawater by flow injection analysis ArchiMer
Laes, Agathe; Vuillemin, Renaud; Leilde, Bernard; Sarthou, Géraldine; Bournot Marec, Claudie; Blain, Stéphane.
A sensitive method for iron determination in seawater has been adapted on a submersible chemical analyser for in situ measurements. The technique is based on flow injection analysis (FIA) coupled with spectrophotometric detection. When direct injection of seawater was used, the detection limit was 1.6 nM, and the precision 7%, for a triplicate injection of a 4 nM standard. At low iron concentrations, on line preconcentration using a column filled with 8-hydroxyquinoline (8HQ) resin was used. The detection limit was 0.15 nM (time of preconcentration = 240 s), and the precision 6%, for a triplicate determination of a I nM standard, allowing the determination of Fe in most of the oceanic regimes, except the most depleted surface waters. The effect of...
Tipo: Text Palavras-chave: Temperature and pressure effects; Submersible chemical analyser; Seawater; In situ measurements; Iron; Flow injection analysis.
Ano: 2005 URL: http://archimer.ifremer.fr/doc/2005/publication-1209.pdf
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