Improvement of microwave-assisted digestion of milk powder with diluted nitric acid using oxygen as auxiliary reagent

Autor(es)

Bizzi, Cezar A. ^{[1, 2]} ; Barin, Juliano S. ^[3] ; Garcia, Edivaldo E. ^[4] ; Nobrega, Joaquim A. ^[5] ; Dressler, Valderi L. ^{[1, 2]} ; Flores, Erico M. M. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Fed Santa Maria, Dept Quim, BR-97105900 Santa Maria, RS - Brazil

^[2] Inst Nacl Ciencia & Tecnol Bioanalit, Campinas, SP - Brazil

^[3] Univ Fed Santa Maria, Dept Tecnol & Ciencia Alimentos, BR-97105900 Santa Maria, RS - Brazil

^[4] Univ Estadual Maringa, Dept Quim, BR-87100900 Maringa, Parana - Brazil

^[5] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY; v. 66, n. 5, p. 394-398, MAY 2011.
• Citações Web of Science: 44

Resumo

The feasibility of using diluted HNO(3) solutions under oxygen pressure for decomposition of whole and non-fat milk powders and whey powder samples has been evaluated. Digestion efficiency was evaluated by determining the carbon content in solution (digests) and the determination of Ca, Cd, Cu, Fe, K. Mg, Mn, Mo, Na, Pb and Zn was performed by inductively coupled plasma optical emission spectrometry and Hg by chemical vapor generation coupled to inductively coupled plasma mass spectrometry. Samples (up to 500 mg) were digested using HNO(3) solutions (1 to 14 mol L(-1)) and the effect of oxygen pressure was evaluated between 2.5 and 20 bar. It was possible to perform the digestion of 500 mg of milk powder using 2 mol L(-1) HNO(3) with oxygen pressure ranging from 7.5 to 20 bar with resultant carbon content in digests lower than 1700 mg L(-1). Using optimized conditions, less than 0.86 mL of concentrated nitric acid (14 mol L(-1)) was enough to digest 500 mg of sample. The accuracy was evaluated by determination of metal concentrations in certified reference materials, which presented an agreement better than 95% (Student's t test, P<0.05) for all the analytes. (C) 2011 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 06/59083-9 - Espectrometria de massa acoplada ao plasma induzido: aspectos fundamentais e aplicações
• Beneficiário: Joaquim de Araújo Nóbrega
• Modalidade de apoio: Auxílio à Pesquisa - Temático