Determinação de chumbo em açúcar por espectrometria de absorção atômica em forno de grafite tratado com tugstênio e ródio / Determination of lead in sugar by graphite furnace atomic absorption spectrometry (GFAAS) treated with tungsten-rhodium

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

A simple method for the direct determination of lead in sugar by graphite furnace atomic absorption spectrometry (GFAAS) with platform treated with 250µg W + 200µg Rh and deuterium background correction is proposed. Samples (8 g) were dissolved in 100 ml of an aqueous solution containing 0,2% v/v HNO3 and 10µl aliquots were co-injected with 5µg Rh into the integrated platform modified with W-Rh of the Universal Varian longitudinal heated graphite atomizer. The characteristic mass (mo) and the method detection limit were 11 pg Pb and 5,0 ng g-1 Pb, respectively, and the tube life time was 860 firings. The relative standard deviation of measurements (n=3) was lower than 2,5 %. For the evaluation of the permanent chemical modifier, parallel experiments were carried in the presence of diluted nitric acid and with the conventional Pd+Mg chemical modifier. Experiments were made either with manual inserted graphite plataforms or integrated plataforms into longitudinal graphite tubes. Comparison of the proposed method with a method based on Pd+Mg chemical modifier showed no statistical differences by applying a t-test at 95% confidence level, for sugar sample solution spiked with lead

ASSUNTO(S)

tungsten-rhodium permanent modifier sugar forno de grafite espectrometria de absorção atômica lead chumbo modificador permanente tungstênio-ródio açúcar atomic absorption spectrometry. graphite furnace

ACESSO AO ARTIGO

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