IWC Annual Report 2003 - Institut für Wasserchemie und chemische ...

1.4 Laser Spectroscopy I
1.4.1 Microanalysis Using the Laser-Induced Plasma Spectroscopy (LIPS) and
VUV-Echelle Spectrograph
Funding: DFG Pa 716/2-1
Cooperation: ISAS, Berlin
Since the early days of laser spectroscopy, laser ablation in combination with optical
emission spectroscopy or mass spectrometry has been utilized for spatially-resolved
analysis. Laser-induced plasma spectroscopy (LIPS, or laser induced breakdown spectroscopy,
LIBS) has been recognized early as potential tool for microanalysis. In
contrast to other techniques), LIPS offers the prospect of a fast and highly automated
at-line analysis without or only minor sample preparation.
The objective of this work was to extend the range of
elements for microanalysis by LIPS, via observation of
atomic emission in the VUV (120-200 nm) range. This
permits not only a multielement analysis of metals, but
also access to emission lines of metalloids such as S, P,
N,O, C, and As. Two experimental set-ups for VUV-LIPS
were realized: A set-up for bulk analysis based on conventional
Czerny-Turner monochromator and a new echelle
spectrograph. With the latter a new set-up for microanalysis
by laser-induced plasma spectroscopy (LIPS) in the
VUV range was designed. The system features an integrated
ablation and detection module with a VUV echelle
which permits a full spectral coverage between 150 and
300 nm with a resolving power between 11000 - 15000.
At present, the ablation module permits a microanalysis
with a crater size of 25 µm and a nominal depth resolution with an ablation rate
of 150 nm per pulse. The VUV performance was demonstrated for bulk analysis of
steel, detection limits for sulphur, carbon, and phosphorus were in the lower mg/kg
range. The VUV scanning and mapping performance for heterogeneous matrices was
illustrated for mineral bottom ash samples from a waste incineration process.
(Igor Radivojevic)
1.4.2 Investigation of the Colloidal Transport in Biological Sewage Plants Using
AF 4 and ICP-MS
Funding: DFG Pa716/4-1
Cooperation: Institute of Water Quality Control and Waste Management, TUM (Prof.
Wilderer)
The goals of this project are the investigation of interactions of artificial tracer colloids
with biofilms in laboratory reactors and technical plants, and the characterization of
hydrocolloids in biological sewage plants. Several spherical lanthanoide(III)phosphate
colloids with different size distribution have been synthesized by slow increase of pH in
solutions which contain soluble rare earth metal salts and phosphoric acid. The best
results have been received with Thulium, which will be used as tracer colloid in the
future. At present experiments at a biofilm reactor containing a bacteria strain, which
is able to degrade 2,4-D are carried out to receive informations about interactions of
tracer colloids with biofilms.
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