W+Rh as permanent chemical modifier in simultaneous atomic absorption spectrometry: interference studies on As, Cd, Pb and Se determination

Journal of the Brazilian Chemical Society

Oliveira, Elisabeth¹  Oliveira, Pedro V¹  Correia, Paulo R. M¹  Universidade de São Paulo, São Paulo, Brazil¹  Nomura, Cassiana S¹ 

关键词: simultaneous atomic absorption spectrometry;    interference;    permanent chemical modifier;   

DOI  :  10.1590/S0103-50532004000100013

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

A systematic study of Na+, K+, Ca2+, Mg2+, Cl-, NO3-, SO42- and PO43- interference on the simultaneous atomization of As, Cd, Pb and Se was carried out using an electrothermal atomic absorption spectrometer. The mixture 250 mg W + 250 mg Rh was thermally deposited on the graphite tube platform and used as permanent chemical modifier. The compromised heating program adjustments (Tp = 650 oC and Ta = 2200 oC) diminished the thermal decomposition and volatilization efficiency of the interfering species during the pyrolysis step. The Cl- and SO42- anions caused the most severe interference, while NO3- only affected the analytes' atomization when high amounts (> 27 mg) were used. The anion PO43- produced a strong negative interference on the Se absorbance signals. The presence of Na+, K+, Ca2+ and Mg2+ prejudiced mainly Cd, and the interference effects of Cl- salts were more pronounced than NO3- salts.

【 授权许可】

Unknown