Publicação
Sequential injection determination of nitrate in vegetables by spectrophotometry with inline cadmium reduction
| Resumo: | 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%. |
|---|---|
| Autores principais: | Oliveira, Sara M. |
| Outros Autores: | Lopes, Teresa I. M. S.; Rangel, António O. S. S. |
| Assunto: | Copperized cadmium column Nitrate Sequential injection analysis Spectrophotometry Vegetables |
| Ano: | 2007 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade Católica Portuguesa |
| Idioma: | inglês |
| Origem: | Veritati - Repositório Institucional da Universidade Católica Portuguesa |
| Resumo: | 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%. |
|---|
Atividades financiadas
Não foram encontrados projetos financiados.