Metals determination in milk powder samples for adult and infant nutrition after focused-microwave induced combustion

Autor: Juliano Smanioto Barin, Erico M.M. Flores, Leticia S. F. Pereira, Lucas Schmidt, Juliana S.F. Pereira, Clarissa M. Moreira
Rok vydání: 2013
Předmět:
Zdroj: Microchemical Journal. 109:29-35
ISSN: 0026-265X
DOI: 10.1016/j.microc.2012.05.010
Popis: In this study, a recently sample preparation method based on focused microwave-induced combustion (FMIC) is proposed for milk powder digestion (for adult and infant nutrition) for subsequent determination of Ba, Ca, Co, Cr, Cu, Fe, Mg, Mn, Sr, V and Zn by inductively coupled plasma optical emission spectrometry (ICP OES). Combustion was carried out under oxygen flow rate (2 to 15 l min − 1 ) using ammonium nitrate (50 μl of 6 mol l − 1 solution) as ignition aid. Samples were pressed as pellets (up to 3 g) and placed on a quartz holder positioned inside the glass vessel. The concentration of the absorbing solution was investigated using nitric acid in the range of 2 to 14 mol l − 1 . Sample digestion was also performed by microwave-assisted wet digestion (MAWD) and by microwave-induced combustion (MIC). Agreement higher than 95% was obtained for all analytes by comparison with certified reference materials of milk powder after FMIC using diluted nitric acid (2 mol l − 1 ) and by comparison of the results obtained by MAWD and MIC. The main advantage of FMIC when compared to MAWD and MIC is the possibility to digest higher sample masses (up to 3 g) achieving better limits of detection. It was possible to use diluted nitric acid solution for analytes absorption and digests were suitable for determination of metals by ICP OES avoiding the use of more expensive instrumentation as inductively coupled plasma mass spectrometry.
Databáze: OpenAIRE
Externí odkaz: