Functions and setup of the contrAA 600
contrAA 600
Edition 01/2014
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The core piece for the graphite tube operation is a transversely heated graphite tube fur-
nace.
The HydrEA technique with the hydride systems of the new generation (HS 55, HS 60 modu-
lar) is the preferred process for the detection-sensitive determination of the hydride-forming
elements As, Bi, Sb, Se, Sn, Te and Hg. The HydrEA technique (“Hydride technique with
electrothermal atomization”) is based on the fact that the metal hydride or mercury vapor is
enriched on the iridium-coated, preheated graphite tube and is atomized at 2100 °C or
800 °C respectively.
Finally, the contrAA 600 with its graphite tube technique is also suitable for the direct solids
analysis in connection with the special sample periphery SSA 600. With the determination of
trace elements directly in the solid sample, the time-intensive and contamination-prone
sample digestion can be eliminated as the main source of error in solution analysis.
Monochromator
The selectivity of the analysis is realized by means of the high-resolution double mono-
chromator based on a prism and an Echelle grating monochromator. This results in a very
compact design paired with a very high spectral resolution (high spectral decomposition of
the radiation) of λ/Δλ =145 000, which corresponds to a spectral bandwidth of < 2 pm/pixel at
200 nm. The monochromator is wavelength stabilized thanks to the use of an integrated
neon radiator. The wavelength accuracy is realized by the internal Ne line calibration of the
monochromator when approaching a wavelength.
Fig. 6
Beam path in the contrAA 600
Detector
At the exit slit of the monochromator, which separates the analysis line from other radiation
from the HCL before it hits the detector in the traditional LS AAS, the HR-CS AAS has a low-
noise, UV-sensitive, semiconductor detector (CCD line detector). Apart from the intensity on
the analysis line, it also registers its spectral vicinity. Thus a spectral area of up to 1 nm is
detected in the vicinity of the analysis line. The detection occurs simultaneously and at a
high resolution.
Analysis unit
The background correction is performed by means of polynomial smoothing via selected
pixels in the spectrum. The user can determine the selection of these receiver pixels manual-
ly. The software, however, provides an automatic default selection. The receiver pixels are
