Expanding the working concentration range for the direct analysis of metallic alloys by on-line anodic electrodissolution and electrothermal atomic absorption spectrometry

The behavior of several absorption lines under different atomization condit ions (from tube wall, L'vov platform and with and without modifier) and the maintenance of the carrier gas flow during atomization were studied with t he objective of expanding the:working concentration range in the determinat ion of Sn, Ni and Fe in brass alloy samples by on-line anodic electrodissol ution and electrothermal atomic absorption spectrometry (ETAAS). The employ ment of several lines and atomization conditions does not seem to affect th e precision with any of the investigated metals. The upper working limit fo r Sn, Ni, and Fe is approximately 1.5, 3.5 and 4.0 times higher, respective ly, under stop gas flow conditions using the less sensitive line than under the most sensitive condition. When combined with the use of resonance line s, non-stop gas flow could be a promising alternative especially for Ni and Fe. The use of non-stop gas flow in combination with non-resonance lines s hould be avoided, The detection limit and the sensitivity can be adjusted b etter, by employing elevated currents in the electrodissolution step. (C) 1 999 Elsevier Science B.V. All rights reserved.