Functions and setup of the contrAA 600
contrAA 600
Edition 01/2014
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5.3
Electrothermal atomizer
Fig. 8
Electrothermal atomizer – graphite tube furnace
The electrothermal atomizer [EA] is an integral part of the contrAA 600 and the core piece for
working in EA mode and the HydrEA technique.
The furnace system is equipped with a graphite tube, which has contact pieces at the side of
the tube jacket for a transversely aligned pipe heater. This transversely heated graphite tube
determines the function. It is the atomizer for the liquid sample injected by means of the
autosampler AS-GF or IC sample carrier supplied via the solids sample periphery and sup-
plied with a small amount of solid substance. At the same time, the transversely heated
graphite tube is also the heating resistor of the electric furnace.
Graphite tube furnace characteristics
Constant temperature ratios along the entire tube length
Realization of linear temperature-time runs according to a sensorless control model
on the basis of saved thermoelectrical parameters and an adaptive control
Protective gas flows, independent of each other and symmetrical to the furnace cen-
ter, which ensure effective graphite tube and furnace window cleaning, and which al-
so ensure fast and safe transport of the thermally disintegrated products of the
sample for disposal
Low consumption of protective gas, at the same time ensuring effective protection
against interference with atmospheric oxygen.
The analytical advantage of the graphite tube technique in conjunction with the background
compensator is the high selectivity problem-free trace and ultra-trace analysis of real sam-
ples with a complex matrix.
In the analysis, each sample runs through a furnace program (temperature-time program)
with the aim of drying wet samples and of separating out any distorting incidental substances
before atomizing.
The furnace program runs in four basic steps:
Drying the sample
