Data/hora: 21/09/2024 18:01:20

Biblioteca(s): 	Embrapa Pecuária Sudeste.	
Data corrente: 	28/08/2000	
Data da última atualização: 	04/01/2022	
Autoria: 	SILVA, F. V.; NOGUEIRA, A. R. de A.; SOUZA, G. B. de; REIS, B. F.; ARAÚJO, A. N.; MONTENEGRO, M. C. M. B. S.; LIMA, J. L. F. C.	
Afiliação: 	FERNANDO V. SILVA, INSTITUTO DE QUÍMICA DE SÃO CARLOS; ANA RITA DE ARAUJO NOGUEIRA, CPPSE; GILBERTO BATISTA DE SOUZA, CPPSE; BOAVENTURA F. REIS, CENTRO DE ENERGIA NUCLEAR NA AGRICULTURA; ALBERTO N. ARAÚJO, CEQUP; MARIA C. M. B. S. MONTENEGRO, CEQUP; JOSÉ L. F. C. LIMA, CEQUP.	
Título: 	Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease.	
Ano de publicação: 	2000	
Fonte/Imprenta: 	Talanta, v.53, p.331-336, 2000.	
Idioma: 	Português	
Conteúdo: 	A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canar;alia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0 x 10 mol urea 1 ', a relative standard deviation of' 1.9% (n = 10) and a sampling rate of 20 samples h-1 ' were observed when 172 Sumner units (SU) of urease and 900 ul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.	
Palavras-Chave: 	Ammonium tubular; Crude extract; Selective electrode; SIA.	
Thesaurus Nal: 	urea.	
Categoria do assunto: 	W Química e Física	
Registro original: 	Embrapa Pecuária Sudeste (CPPSE)	
Exemplares: 	CPPSE - (12992-1) - UPC - AP - DD - PROCI-2000.00016 - SIL - 2000.00016 - DIS