title: Causes and elimination of systematic errors in the determination of iron and cobalt in aqueous solutions in the ng/ml and pg/ml range.
abstract: The determination of very low levels of elements, in the ng/g and pg/g range, is very closely linked with different systematic errors causing considerable discrepancies in the analytical results for real samples. Main sources of these errors are blanks as well as losses of elements and compounds by volatilization and adsorption. In this paper, systematic errors arising from contamination of the sample solution by the vessels and the dust content of the air are demonstrated for determination of iron and cobalt at pg/ml and ng/ml levels in pure aqueous solutions by AAS with electrothermal atomization. Effective cleaning procedures are described for different vessel materials such as PTFE, quartz and glass. Blanks due to airborne dust can be substantially reduced by working on clean-benches in clean-rooms.
authors.affiliation: Max-Planck-Institute for Metal Research, Institute of Materials Science, Laboratory for High-Purity Materials, Katharinenstrasse 17, D-7070 Schwäbisch Gmünd, F.R.G.
authors.forename: K
authors.initials: K
authors.lastname: Gretzinger
authors.forename: L
authors.initials: L
authors.lastname: Kotz
authors.forename: P
authors.initials: P
authors.lastname: Tschöpel
authors.forename: G
authors.initials: G
authors.lastname: Tölg