Data/hora: 17/06/2024 17:17:09

Biblioteca(s): 	Embrapa Pecuária Sudeste.	
Data corrente: 	13/05/2003	
Data da última atualização: 	09/06/2022	
Autoria: 	ARAÚJO, G. C. L.; GONZALEZ, M. H.; FERREIRA, A. G.; NOGUEIRA, A. R. de A.; NÓBREGA, J. A.	
Afiliação: 	GEÓRGIA C. L. ARAÚJO, UFSCAR; MÁRIO H. GONZALEZ, UFSCAR; ANTÔNIO G. FERREIRA, UFSCAR; ANA RITA DE ARAUJO NOGUEIRA, CPPSE; JOAQUIM A. NÓBREGA, UFSCAR.	
Título: 	Effect of acid concentration on closed-vessel microwave-assisted digestion of plant materials.	
Ano de publicação: 	2002	
Fonte/Imprenta: 	Spectrochimica Acta part B, v.57, n.12, p.2121-2132, 2002.	
DOI: 	https://doi.org/10.1016/S0584-8547(02)00164-7	
Idioma: 	Inglês	
Conteúdo: 	The efficiency of microwave-assisted acid digestion of plants using different concentrations of nitric acid (2.0, 3.0, 5.0, 7.0 and 14 mol l-1) with hydrogen peroxide (30% v/v) was evaluated by measuring the residual carbon content (RCC) using inductively coupled plasma optical emission spectrometry (ICP-OES) with axial viewing. Certified reference materials were used for evaluating the accuracy attained when 2 mol l-1 HNO3 was employed for digestion. Under all experimental conditions RCC values were always lower than 13% w/v, and even the highest concentration did not cause any interference with element recovery. It seems that the high pressure reached for closed-vessel operation improved the oxidative action of nitric acid due to consequent temperature increase, even when this reagent was not used at high concentrations. According to acid?base titration data, residual acid in the digestates varied from 1.2 to 4.0 mol l-1, depending on the acid concentration initially added. It can be concluded that for plant materials, microwave-assisted acid digestion can be carried out under mild conditions, which implies that digestates do not need extensive dilution before introduction by pneumatic nebulization to ICP-OES. An additional advantage is the lower amount of residue generated when working with less concentrated acid solutions.	
Palavras-Chave: 	Acid digestion; Closed vessel; Inductively coupled plasma optical emission spectrometry (ICP-OES; Microwave-assisted digestion; Plant materials; Residual carbon content.	
Categoria do assunto: 	W Química e Física	
Registro original: 	Embrapa Pecuária Sudeste (CPPSE)	
Exemplares: 	CPPSE - (14446-1) - UPC - AP - DD - PROCI-2002.00171 - ARA - 2002.00171 - DIS