Determination of heavy metals in sea water and in marine organisms by graphite furnace AAS

Summary This paper is a plea for a reference material containing extremely low concentrations of Pb and Cd. A reasoning is given by a historical overview on the main topics of pollution research in relation to those metals. Emphasis has changed from toxicological tests (with high concentrations) over hot spots in the environment (certain organisms and organs, such as kidney and liver, showing significantly elevated concentrations) to mechanisms of transport and modelling. That development has been accompanied and promoted by methodological improvement. Those concentrations, which have to be determined with a sufficiently high precision are now in the lower background range. A proper standard material for such purpose could be fish muscle which, over and above, could be spiked, if necessary, for measurements in a higher concentration range.

---

Bestimmung von Schwermetallen in Meerwasser und marinen Organismen mit Hilfe der Graphitofen-AASXXII. Fischmuskel an Stelle von Leber und Algen als Referenzmaterial für Blei- und Cadmiumbestimmungen

---

Part XXI. Cadmium determination in coastal water samples from the German Bight (1985) Vom Wasser 64:53–68     

Determination of heavy metals in sea water and in marine organisms by flameless atomic absorption spectrophotometry

Summary This paper presents results of an intercalibration of cadmium determination by means of flameless AAS in biological materials from toxicological experiments. Furthermore, the philosophy of this kind of investigation is discussed in some detail. The goal and the result of this investigation was a correspondence of the measurement results within an acceptable range. Contamination during further handling has been identified as the main reason for severe deviations. The authors made measurements in the labs of several colleagues. The equipment itself did not produce individual variations. Repeated intercomparison after elimination of identified systematic errors showed sufficient correspondence of the results.Teil XII: Fresenius Z. Anal. Chem.301, 294–299 (1980)     

On batch homogeneity in horizontal CVD reactors (II). HCl gas-phase etching

A general model of the depletion is given, to which the reactive component of the reaction gas mixture in a horizontal CVD-reactor is subjected during its flow along the heater. Furthermore the model of heating the process gas, described in Part I of this work, is used to derive an expression of the dependence of the thickness δ of the boundary layer upon the x-coordinate (direction of the flow). Both models are combined to get a model of longitudinal homogeneity of wafer processing in an CVD-reactor, which is applied to the special case of HCl gas phase etching. The predictions derived using the model were compared with experimental results.