Sequential injection determination of nitrate in vegetables by spectrophotometry with inline cadmium reduction

Sara M. Oliveira, Teresa I. M. S. Lopes, António O. S. S. Rangel*

*Autor correspondente para este trabalho

Resultado de pesquisarevisão de pares

12 Citações (Scopus)
11 Transferências (Pure)

Resumo

A sequential injection system for the determination of nitrate (NO 3-) in vegetables was developed to automate this determination, allowing for substantially reduced reagent consumption and generated waste using low-cost equipment. After extraction with water and filtration, the extracted nitrate is reduced inline to nitrite in a copperized cadmium (Cd) column and determined as nitrite. According to the Griess-Ilosvay reaction, nitrate is diazotized with sulfanilamide and coupled with N-(1-naphtyl)-ethylenediamine dihydrochloride to form a purple-red azo dye monitored at 538 nm. Nitrate can be determined within a range of 1.35-50.0 mg L-1 of NO3- (corresponding to 0.270-10.0 g of NO3- per kg of vegetable), with a conversion rate of nitrate to nitrite of 99.1 ± 0.8%. The results obtained for 15 vegetable extracts compare well with those provided by the classical procedure, with a sampling throughput of 24 determinations per hour and relative standard deviations better than 1.2%.

Idioma originalEnglish
Páginas (de-até)533-544
Número de páginas12
RevistaCommunications in Soil Science and Plant Analysis
Volume38
Número de emissão3-4
DOIs
Estado da publicaçãoPublicado - fev. 2007

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