Determination of total nitrogen in food by flow injection analysis (FIA) with a potentiometric differential detection system

• Tipo: Artigo em Revista Científica Internacional
• Data: 1999

Autores

Lima, JLFC (Autor) FFUP; Montenegro, MCBSM (Autor) FFUP; Pinto, APMMO (Autor) Outra

Revista

Título: Fresenius' Journal of Analytical Chemistry

Vol. 364

Páginas: 353-357

ISSN: 0937-0633

Editora: Springer

Indexação

ISI Web of Knowledge - 11 Citações

Scopus - 12 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-001-465

DOI: 10.1007/s002160051348

Abstract (EN): A flow injection set-up based on potentiometric detection and gas diffusion device for the determination of total nitrogen in food is described. The detection system consisted of two ammonium-sensitive electrodes placed sequentially and each alternately operating as reference electrode. Tubular electrodes without an inner reference solution were prepared with a PVC membrane composed of nonactin in Tris (2-ethylhexyl) phosphate and potassium tetrakis (4-chlorophenyl) berate to reduce the membrane resistance. The food sample digests were inserted into the system, and the ammonium present was converted into ammonia gas. The gas diffused through a gas-permeable membrane to a buffer acceptor stream with a pH that ensured transformation to the ammonium cation, which was potentiometrically detected. Good agreement between FIA results and those provided by the reference procedure was obtained, with relative deviation errors below 5%. Using the proposed system, low reagent consumption is possible, a sampling rate of about 30 samples/h was achieved, as well as a good reproducibility for consecutive injections of the same sample (variation coefficient < 2%).

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 5