Verlag des Forschungszentrums Jülich
JUEL-3695
The method development included separation of 12 naturally occurring arsenic species
by high-performance liquid chromatography (HPLC) followed by an arsenic selective
detection by inductively coupled plasma-mass spectrometry (ICP-MS). The arsenic
species As (III), As (V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA),
arsenobetaine (AB), arsenocholine (AC), trimethylarsine oxid (TMAO) and
tetramethylarsonium (Tetra) were separated with ion-exchange chromatography, whereas
reversed-phase chromatography was used for the separation of four arsenosugars.
Because of the partly low arsenic concentration in biological samples a very good
detection power was required. Therefore, an HPLC-ICP-MS system was tested with
different nebulizers. Using the high efficiency nebulizer HHPN (Hydraulic High
Pressure Nebulizer), detection limits in the low pg-range could be achieved.
An important step in speciation analysis is the extraction of the samples. Specific
studies have been performed for comparing the extraction of fresh and freeze-dried
material. It was shown that the extraction efficiencies for fresh samples were
almost 100 % whereas for some freeze-dried samples a lower extractability was found.
The developed analytical methods were applied to arsenic speciation in four marine
matrixes, which are representative of different trophic levels in the food chain.
All samples originated from an ecosystem in the North Sea. In the extracts of common
mussels, eel-pout muscles and sea gull eggs the species AB was found to be the major
component of the detected arsenic species beside of small amounts of other known
and unknown arsenic compounds. Bladderwrack contained mostly arsenosugars. The
contents of the inorganic arsenic species were at a very low level in all analyzed
samples. Regarding the mass balances it was found that a certain amount of arsenic
could not be detected in most of the matrices. Therefore, it is assumed that these
samples contain unknown arsenic species, e.g. arsenolipids or arsenoproteins.
Investigations of bream, a limnic fish, showed differences with respect to arsenic
species pattern and mass balance in comparison to the marine fish eel-pout.
Furthermore, it was found that the arsenic pattern of a specific bioindicator was
depending on the ecosystem. As examples, mussels from the North Sea and the Baltic
Sea as well as bream from different rivers in Germany were characterized.
Falk, Kirsten
Speciation von Arsen in biologischen Umweltproben aus aquatischen Ökosystemen mittels HLPC-ICP-MS
137 S., 1999
The physicochemical forms of arsenic (arsenic species) which are present in the
environment vary significantly with respect to toxicity, bioavailability, stability
and transport behaviour. Therefore, it is necessary for an assessment of the toxic
potential to humans and the environment to investigate not only the total arsenic
concentrations but also to differentiate the single species. By that the knowledge
about ecological correlations and pathways will be increased. The present thesis
reports the results of a Ph.D. study on the development and optimisation of analytical
methods for arsenic speciation and their application to biological samples from
different aquatic ecosystems in Germany.
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