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Orientador(es)
Resumo(s)
A sequential injection system for the determination of nitrate (NO3
2) 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 L21 of NO3 2 (corresponding
to 0.270–10.0 g of NO3 2 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%.
Descrição
Palavras-chave
Copperized cadmium column Nitrate Sequential injection analysis Spectrophotometry Vegetables
Contexto Educativo
Citação
"Communications in soil science and plant analysis". ISSN 0010-3624. 38: 3-4 (2007) 533-544
Editora
Taylor & Francis Group