Simultaneous determination of Cd and Fe in sewage sludge by high-resolution continuum source electrothermal atomic absorption spectrometry with slurry sampling

This work describes the method development for the simultaneous determination of Cd and Fe using the main resonance line of Cd at 228 802 nun and a secondary Fe line at 228.725 nm, and high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS ET AAS) Two certified reference materials and two 'real' samples of industrial and domestic sewage sludge have been analyzed as slurries prepared in a mixture of HF and HNO3 The simultaneous determination has been performed using a short temperature program of only 30s, without a pyrolysis stage and with two atomization stages, at 1300 degrees C and 2300 degrees C, taking into consideration the significantly different thermal characteristics of Cd and Fe Structured background, which is likely due to the presence of one or more diatomic molecules, including SiO, has been detected. However, there has been no spectral overlap between molecular bands and the atomic lines of Cd and Fe, making possible the determination to be carried out using only automatic correction for continuous background Calibration against aqueous standards lead to good agreement between certified or informed values and the determined values, at a statistical confidence level of 95%, recovery tests were performed for real samples, resulting in recoveries ranging from 90 to 105%. Detection limits of 003 and 90 mu g g(-1) for Cd and Fe, respectively, have been obtained, which are adequate for the purpose (C) 2010 Elsevier B V All rights reserved