Determination and fractionation of barium in Brazil nuts

Abstract

, respectivamente. Esses resultados indicaram a indisponibilidade de bário presente nesse alimento ao organismo humano. Baseando-se nos teores de bário e enxofre nas diferentes frações e em cálculos estequiométricos para as possíveis reações envolvidas pode-se inferir que bário se encontra principalmente na forma de BaSO 4 . Experimentos termogravimétricos também confirmaram essa suposição.Several sample preparation strategies were employed for determination and fractionation of barium in Brazil nuts using measurements by graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma optical emission spectrometry with axial view (ICP OES). This food is widely consumed because of its nutritional value and good taste. The chemical analysis of Brazil nuts is not trivial due to their complex matrix. The fractionation of barium in Brazil nuts was studied owing to the toxicity of this element and the strong correlation between chemical form and absorption. Total concentrations of barium varied from 860 to 2084 mg kg -1 . Sequential extractions were performed based on solubility in different media and also according to lipids, proteins and low molecular weight fractions (LMW). The greatest contents of barium were determined in the LMW and in the water insoluble fractions with concentrations in the range 778 to 1606 and 551 to 1520 mg kg -1 , respectively. Based on these results it can be inferred that Ba is not absorbed when Brazil nuts are ingested. Considering both the contents of barium and sulfur in different fractions and stoichiometric calculations it was also possible to assume that barium occurs mainly in the BaSO 4 form. The presence of this chemical form was also confirmed by thermogravimetric measurements.

Analytical chemistry in Brazil: healthy and growing

“…There are typical tropical products, such as Brazil nuts, babassu nuts and sapucaia, which require the development of tailored procedures for determining chemical forms of a specific element, such as barium in Brazil nuts, 40 and arsenic, cadmium and lead in diverse products. 41 Demands imposed by legislation may be exemplified by the determination of folic acid and minerals in corn and wheat flours.…”

Evaluation of inductively coupled plasma mass spectrometry for determining Ca, Cu, Fe, Mg, Mn, Se and Zn in bovine semen samples using a simple sample dilution method

“…8,[10][11][12][13][14] The semen analysis is also useful in the evaluation of the exposure to toxic metals in the environment. 1,6 The analysis of trace elements in biological samples is predominantly performed using atomic spectrometry techniques, such as atomic absorption spectrometry (AAS), [15][16][17][18][19][20][21][22][23] inductively coupled plasma emission spectrometry (ICP-OES) 24 and inductively coupled plasma mass spectrometry (ICP-MS). [25][26][27][28][29] ICP-MS offers several advantages, including simultaneous multielement measurement capability coupled with very low limits of detection, a wider linear dynamic range, allowing the determination of major and trace elements at the same sample injection and isotopic information.…”

Avaliação da distribuição de cobre associado a compostos de diferentes massas moleculares na polpa de açaí

“…Técnicas seletivas e com adequada sensibilidade têm sido usadas para detecção de elementos em estudos de fracionamento, distribuição e especiação química (Gonçalves et al 2009; Naozuka e Oliveira 2007; Kannamkumarath et al 2002). A espectrometria de absorção atômica em forno de grafite (GF AAS) é uma técnica analítica bem estabelecida e suficientemente robusta para ser implantada em laboratórios envolvidos com rotina em larga escala (Welz 1999).…”