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Use este identificador para citar ou linkar para este item: https://repositorio.ufba.br/handle/ri/6022
Tipo: Artigo de Periódico
Título: Comparison of direct solid sampling and slurry sampling for the determination of cadmium in wheat flour by electrothermal atomic absorption spectrometry
Título(s) alternativo(s): Talanta
Autor(es): Araujo, Rennan Geovanny Oliveira
Oleszczuk, Nédio
Rampazzo, Roger T.
Costa, Pedro A.
Silva, Márcia M.
Vale, Maria Goreti R.
Welz, Bernhard
Ferreira, Sergio Luis Costa
Autor(es): Araujo, Rennan Geovanny Oliveira
Oleszczuk, Nédio
Rampazzo, Roger T.
Costa, Pedro A.
Silva, Márcia M.
Vale, Maria Goreti R.
Welz, Bernhard
Ferreira, Sergio Luis Costa
Abstract: Two analytical methods for the determination of cadmium in wheat flour by electrothermal atomic absorption spectrometry without prior sample digestion have been compared: direct solid sampling analysis (SS) and slurry sampling (SlS). Besides the conventional modifier mixture of palladium and magnesium nitrates (10 g Pd+3 g Mg), 0.05% (v/v) Triton X-100 has been added to improve the penetration of the modifier solution into the solid sample, and 0.1% H2O2 in order to promote an in situ digestion for SS. For SlS, 30 g Pd, 12 gMg and 0.05% (v/v) Triton X-100 have been used as the modifier mixture. Under these conditions, and using a pyrolysis temperature of 800 ◦C, essentially no background absorption was observed with an atomization temperature of 1600 ◦C. About 2mg of sample have been typically used for SS, although as much as 3–5mg could have been introduced. In the case of SlS multiple injections had to be used to achieve the sensitivity required for this determination. Calibration against aqueous standards was feasible for bothmethods. The characteristic mass obtained with SSwas 0.6 pg, and that with SlSwas 1.0 pg. The limits of detection were 0.4 and 0.7 ng g−1, the limits of quantification were 1.3 and 2.3 ng g−1 and the relative standard deviation (n = 5) was 6–16% and 9–23% for SS and SlS, respectively. The accuracy was confirmed by the analysis of certified reference materials. The two methods were applied for the determination of cadmium in six wheat flour samples acquired in supermarkets of different Brazilian cities. The cadmium content varied between 8.9±0.5 and 13±2ngg−1 (n = 5). Direct SS gave results similar to those obtained with SlS using multi-injections; the values of both techniques showed no statistically significant difference at the 95% confidence level. Direct SS was finally adopted as the method of choice, due to its greater simplicity, the faster speed of analysis and the better figures of merit.
Palavras-chave: Cadmium
Wheat flour
Slurry sampling
Solid sampling
ET AAS
URI: http://www.repositorio.ufba.br/ri/handle/ri/6022
Data do documento: 2008
Aparece nas coleções:Artigo Publicado em Periódico (Química)

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