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8451191 
Journal Article 
Behaviour of chromium in the graphite furnace during the performance of the flameless absorption spectrometry 
Arpadjan, S; Krivan, V 
1988 
0 
Fresenius' Zeitschrift für Analytische Chemie
ISSN: 0016-1152 
329 
7 
745-749 
English 
By means of51Cr as radiotracer, the behaviour of chromium in the graphite tube during the individual steps of the temperature program was investigated. The investigated matrix systems include 1 mol/l HCl, 0.2 mol/l HNO3, 0.2 mol/l NaCl, human serum and urine, cow milk, a tetramethylammonium hydroxide solution of hair, a solution of Cr-diethyldithiocarbamate in MIBK, and a HF/ HNO3/H2O2 solution of niobium. Excluding the last two matrices, the labelling was carried out with both the51Cr3+ and51CrO42-. Without matrix modification, a charring temperature between 1200 °C and 1400 °C can be used for the investigated samples. No significant difference was observed between uncoated and pyrolytically coated tubes. Significant stabilization effects can be achieved in the pre-atomization step by using tungsten-coated tubes and/or matrix modifiers of which Na2WO4, Na2MoO4 and H2O2 proved to be well suited. Optimum experimental conditions were found for the execution of the atomization step. The results obtained in some special experiments indicate that no strong retention of chromium on the surface of the graphite tube by carbide formation is taking place. © 1988 Springer-Verlag.