[Zurück]

E. Rosenberg:
"Environmental Speciation of Germanium";
Hauptvortrag: ECOpole'07, Jamrozowa Polona (b. Wroclaw), Polen (eingeladen); 17.10.2007 - 20.10.2007.

Speciation analysis allows to determine the different forms in which an element is present in the environment [1]. Its importance has considerably grown since it was realised that the essentiality or toxicity, bioavailabiliy and persistence in the environment strongly depend on the form in which this element is present [2]. Early interest in speciation analysis focused on low molecular weight, environmentally relevant species of the elements tin, lead and mercury [3]. Eventually, speciation analysis developed to include also elemental species other than organometallic compounds or redox species and to turn the eyes to environmental remediation, physiology, plant biology, or the large field of pharmaceuticals and "nutraceuticals". Still, most of the work is concentrated on some few additional elements such as arsenic, or selenium [4]. A large part of the periodic table of the elements remained and still today remains un-investigated.
This is also true for the element germanium. Germanium is less abundant than either tin or lead (its homologous elements from group 14), and tends to be widely dispersed, however at low concentrations. World production is about 80 tonnes per year. Germanium is an important semiconductor, and also used in the glass industry for optical specialty products. Organic compounds are known, but not generally encountered in the environment: Organoalkyl compounds are used in few industrial processes. The only organo-germanium compound of great relevance is the so-called germanium sesquioxide or Ge-132 (= Bis(2-carboxyethylgermanium) sesquioxide). This compound is said by its supporters to be a potent inhibitor of cancer and HIV, as well as of other diseases [5]. Irrespective of whether this can scientifically be supported or not, the market for this compound is thus continuously growing, with the production often being in small factories under hardly controlled conditions. As the inorganic counterpart, GeO2, however, is highly toxic to humans, a rigid control of the "organic germanium" is required for the absence of inorganic germanium. Clearly, methods for total element determination are unsuccessful here. As the properties of the various germanium species are largely different, there cannot be a universal method for the determination of all species in one procedure. We therefore propose different approaches for the species-specific determination of germanium sesquioxide and other germanium species. These approaches are based on gas- or liquid chromatography based hyphenated techniques, with compound specific (mass spectrometric) or with element specific (atomic emission) detection [6]. Such procedures have not been described earlier in the literature. We will therefore thoroughly discuss the advantages and disadvantages of the methods developed in house in the frame of this presentation.

References:
[1] D. M. Templeton, F. Ariese, R. Cornelis, L.-G. Danielsson, H. Muntau, H.P. van Leeuwen, and R. Lobinski, Pure Appl. Chem. 72 (2000) 1453-1470.
[2] L Ebdon, L Pitts, R Cornelis, H Crews, O F X Donard and Ph Quevauviller (eds.), Trace Element Speciation for Environment, Food and Health, Royal Society of Chemistry, Cambridge, 2001.
[3] R. Lobinski, Appl. Spectrosc., 51 (1997) 260A-278A.
[4] J. Szpunar, R. Lobinski, and A. Prange, Appl. Spectrosc. 57 (2003) 102A-112A.
[5] S. Goodman, Germanium - The health and life enhancer, http://www.positivehealth.com/permit/Articles/Nutrition/Germanium/intro.htm
[6] see website of the European Virtual Institute for Speciation Analysis, EVISA at: www.speciation.net

speciation, environmental analysis, sample preparation, Germanium