Data/hora: 08/06/2024 02:22:03

Biblioteca(s): 	Embrapa Pecuária Sudeste.	
Data corrente: 	18/08/2005	
Data da última atualização: 	13/03/2023	
Autoria: 	SANTOS, D. M.; PEDROSO, M. M.; COSTA, L. M.; NOGUEIRA, A. R. de A.; NÓBREJA J. A.	
Afiliação: 	DANIELE M. SANTOS, Universidade Federal de Uberlândia; MARIELE M. PEDROSO, Universidade Federal de São Carlos; LETICIA M. COSTA, Universidade Federal de São Carlos; ANA RITA DE ARAUJO NOGUEIRA, CPPSE; JOAQUIM A. NOBREGA, Universidade Federal de São Carlos.	
Título: 	A new procedure for bovine milk digestion in a focused microwave oven: gradual sample addition to pre-heated acid.	
Ano de publicação: 	2005	
Fonte/Imprenta: 	Talanta, v. 65, n. 2, p. 505-510, jan. 2005.	
DOI: 	https://doi.org/10.1016/j.talanta.2004.07.013	
Idioma: 	Inglês	
Conteúdo: 	Milk samples can be efficiently digested using a focused microwave oven, however the conventional procedure of addition of concentrated acids to the liquid sample leads to digestates with elevated acidity and residual carbon concentrations. In this work a focused microwave oven was applied for acid digestion of bovine milk samples using a conventional and an alternative procedure based on gradual sample addition to hot and concentrated acids. A two-level 23 full factorial design experiment with eight runs was carried out to evaluate the optimum experimental conditions for reducing both the residual carbon and the final acidity of digestates. The three studied parameters were: temperature of the digestion medium for sample addition, addition of sulfuric acid before the sample or during the first step, and number of aliquots of the sample gradually added. The best conditions were attained by adding small aliquots of milk (ten-fold a volume of 0.5 ml added during 5.0 min) to a digestion mixture containing 3.0 ml nitric acid plus 1.0 ml sulfuric acid heated at 105 °C. It was demonstrated that the digestion efficiency of the alternative procedure was better than the conventional procedure, i.e. 98 and 80%, respectively. The alternative procedure was applied for determination of Ba, Ca, Cu, K, Mg, Na, P, and Zn in whole and non-fat bovine milk. The accuracy was proved using two certified reference materials (whole and non-fat milk powder).	
Palavras-Chave: 	Bovine milk; Focused microwave assisted digestion; Pre heated acid; Sample addition.	
Thesagro: 	GADO DE CORTE; GADO LEITEIRO.	
Categoria do assunto: 	W Química e Física	
Registro original: 	Embrapa Pecuária Sudeste (CPPSE)	
Exemplares: 	CPPSE - (15813-1) - UPC - AP - DD - PROCI-2005.00107 - SAN - 2005.00107 - DIS