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Advisor(s)
Abstract(s)
In this work, a sequential injection methodology for monitoring nitrite and nitrate in estuarine waters
without any previous treatment is described. The developed system was applied to the measurement
of nitrite and nitrate in estuarine waters of three rivers in the NW Portugal, allowing an automatic, fast
(ca 60 h 1) and precise method (relative standard deviation lower than 2%). The procedure was based
on the reaction between nitrite, sulfanilamide and N-(1-naphthyl)-ethylenediamine dihydrochloride
(N1NED), whereas the determination of nitrate resulted from its reduction to nitrite, using an in-line
cadmium column, followed by the same reaction. The samples were collected in three locations for
each river (Douro, C avado and Ave) covering the lower, middle and upper section of the estuaries.
Despite the presence of a salinity gradient, this parameter showed no interference in the accuracy of
the determinations. The results obtained for the described method for nitrite were statistically
comparable to those obtained by the reference procedure. For the determination of nitrate, recovery
tests confirmed that the sequential injection methodology provided good quality results.
Description
Keywords
Pedagogical Context
Citation
"Analytical Methods". ISSN 1759-9660.1 (2009) 195–202
Publisher
The Royal Society of Chemistry