Development of a sequential injection system for the determination of nitrite and nitrate in waters with different salinity: Application to estuaries in NW Portugal

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Ribeiro Mesquita, RBR (Author) Other; Oliveira Barbosa Ferreira, MTSOB (Author) Other; Alves Segundo, RLA (Author) Other; Carvalho Pinheiro Teixeira, CFCP (Author) Other; Adriano Bordalo (Author) ICBAS; Santos Silva Rangel, AOSS (Author) Other

Journal

Title: Analytical Methods

Vol. 1

Pages: 195-202

ISSN: 1759-9660

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 11 Citations

Other information

Authenticus ID: P-003-DPN

DOI: 10.1039/b9ay00101h

Abstract (EN): 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, Cavado 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8