Ensaio de um redutor de cádmio aplicado à determinação do teor de nitrito e nitrato da Baía de Maputo

Abstract

The present work entitled “Test of a Cadmium Reducer Applied to the Determination of Nitrite and Nitrate Content in Maputo Bay Waters” is part of the environmental research program at the Department of Chemistry at UEM. It is the assembly and effôaio of a tubular reducer with a view to verifying its applicability in the bay's waters. Based on the work with this instrument, the results on the levels of nitrate and nitrite in samples taken in Maputo Bay in May 1997 are presented. Nitrite determinations were carried out based on the diazotization method in the presence of sulphanilic acid and N-(1-naphthyl)-ethylenediamine, with formation of complexes whose absorbance was then measured in a spectrophotometer in the visible region. For the determination of nitrate, the method of reduction to nitrite with cadmium amalgam was used. The spectrophotometric part of the analysis is similar to the case of nitrite determination. Based on the results obtained, it can be concluded that the nitrate content in the Maputo Bay area during the study period corresponded to an average of 1.0pmol/L and that of nitrite, 0.2pmol/L, which are normal values ​​in bays and estuaries.(TRADUÇÃO NOSSA)