Determination of cadmium in sediments and in sewage sludge by slurry sampling electrothermal atomic absorption spectrometry using iridium as permanent modifier

Journal of the Brazilian Chemical Society

Daniel L. G. Borges¹  Lúcia F. Dias¹  Márcia A. M. S. Da Veiga¹  Adilson J. Curtius¹ 

[1] ,Universidade Federal de Santa Catarina Departamento de Química Florianópolis SC ,Brazil

关键词: cadmium;    slurry;    ET AAS;    modifier;    sediment;    sewage sludge;   

DOI  :  10.1590/S0103-50532003000200017

来源: SciELO

【 摘 要 】

A procedure for the determination of Cd in sediment and sewage sludge as slurries by electrothermal atomic absorption spectrometry is proposed. The slurry, 1 mg mL-1, was prepared by mixing sample ground to a particle size £ 50 mm with 5% v/v nitric acid in an ultrasonic bath. The homogeneity of the slurries was assured by passing a constant flow of argon into the autosampler cup, just before transferring an aliquot to the graphite furnace. Two permanent modifiers deposited on the platform were tested: Ru and Ir. Modifiers in solution were also tested: Pd plus Mg and phosphate alone or plus Mg. The Ir-treated tube was adopted due to its good performance as modifier and also for practical reasons. About 80% of Cd is extracted to the water phase of the slurry. To test the accuracy of the method, three certified materials were analyzed: a marine sediment, a river sediment and a domestic sewage sludge. The concentrations obtained, using calibration against aqueous standards prepared in the same medium as the slurries, are in agreement with the certified values, at a confidence level of 95%, according to the Student-t test. The limit of detection (3s) was 43 ng g-1 in the solid sample and the relative standard deviation for the sediment MESS-2 was 2.3% (n = 10).

【 授权许可】

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