Author(s):
Barbosa, José Tiago Pereira ; Santos, Clarissa Marques Moreira ; Bispo, Lilia dos Santos ; Lyra, Fernanda Henrique ; David, Jorge Mauricio ; Korn, Maria das Graças Andrade ; Flores, Erico Marlon Moraes ; Barbosa, José Tiago Pereira ; Santos, Clarissa Marques Moreira ; Bispo, Lilia dos Santos ; Lyra, Fernanda Henrique ; David, Jorge Mauricio ; Korn, Maria das Graças Andrade ; Flores, Erico Marlon Moraes
Date: 2015
Origin: Oasisbr
Subject(s): Soybean analysis; Microwave-induced combustion; Food analysis; Halogens; ICP-MS
Description
Texto completo: acesso restrito. p.1065-1070
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Made available in DSpace on 2015-03-11T12:46:32Z (GMT). No. of bitstreams: 1 José Tiago Pereira Barbosa.pdf: 153492 bytes, checksum: 7bb0eba73be6edefbb359040f1743c1b (MD5) Previous issue date: 2013
A method for bromine, chlorine, and iodine determination in soybean and related products was developed by inductively coupled plasma mass spectrometry (ICP-MS) after digestion by microwave-induced combustion (MIC). Samples were pressed as pellets and combusted using pressurized oxygen (20 bar) and ammonium nitrate solution (50 μL of 6 mol L−1) as the igniter. Analytes were absorbed in alkaline solution (100 mmol L−1 NH4OH), and a reflux step of 5 min, microwave power of 1,400 W, was applied after combustion in order to improve analyte recoveries. For Cl determination by ICP-MS, a dynamic reaction cell was used with ammonia as the reaction gas. The accuracy was evaluated using certified reference materials (CRMs) and spiked samples. Using MIC, the agreement with CRM values and spike recoveries was higher than 95 % for all analytes for certified reference materials of a similar composition (National Institute of Standards and Technology (NIST), corn bran and NIST, whole milk). Limits of detection were 0.03, 1.2, and 0.002 μg g−1 for Br, Cl, and I, respectively. The residual carbon content in the digests obtained after MIC procedure was lower than 0.5 %. Blanks were always negligible and no memory effects were observed. Digestion by MIC allowed processing up to eight samples by each run in 25 min with high efficiency of digestion providing a suitable medium for further bromine, chlorine, and iodine determination by ICP-MS.
