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For trace analysis of toxic elements it is not only the re q u i rement to determine the total content of the element in question at lower and lower leve l s , but add it i o n a l ly to elucidate the binding state in wh i ch it is ap p e a ring with the aim to eva l u ate the ecotoxicity and to fo l l ow the pat h ways of these elements in the env i ronment and their m e t abolism in biological systems. Speciation of toxic as we l l as of essential elements is there fo re of increasing intere s t .For analysis of metals bound to biomolecules usually o rganic mass spectro m e t ry is applied convincing by high s e n s i t ivity and abilities for identifi c ation. On the other hand atomic spectro m e t ry has often been applied to determ i n e t oxic and essential metals in many diffe rent compounds and is more and more used for speciation in most cases as a single element detector with high sensitiv i t y.S p e c i ation of metals and semi-metals has a long analy t ical tra d i t i o n , as has been rev i ewed re c e n t ly by Lobinski [1]. For sep a ration of the diffe rent inorganic and organic species, ch ro m at ographic tech n i q u e s , e s p e c i a l ly liquid ch ro m at ograp hy (LC) [2], gas ch ro m at ograp hy (GC) [3][4][5], s i ze -ex cl usion ch ro m at ograp hy (SEC) [6] and high perfo rmance LC (HPLC) [7][8][9][10] have been applied in combination with diffe rent detectors. While for gas ch ro m at ographic detection a number of diffe rent powerful detectors ex i s t , t h e re is a certain lack of sensitive and selective detectors for liquid ch rom at ograp hy. UV-Vis detection, for ex a m p l e, is often ap p l i e d, but its selectivity as well as sensitivity often are not suffic i e n t , wh e reas electro chemical detection shows both high s e n s i t ivity and selectivity but is ap p l i c able only for ch a rge d compounds. This is the reason why for LC techniques new d e t e c t o rs are still re q u i re d. Recently, n ew techniques based on emission spectro m e t ry are intro d u c e d, among wh i ch ex c it ation sources as microwave induced plasmas (MIP) or i n d u c t ive ly coupled plasmas (ICP) we re favo u re d, p a rt i a l ly in combination with hy d ride techniques. Howeve r, in most cases the detection limits we re not low enough for determ in ation of all species of interest at trace levels in complex m at rices. Th e re fo re improvement of detection limits was in p a rticular expected from ap p l i c ation of mass spectro m e t ry.I n d u c t ive ly coupled plasma mass spectro m e t ry (ICP-MS) was shown to be a powerful detection technique for speciation by LC, HPLC and GC [11][12][13]. ICP-MS is not only a ve ry selective but also a ve ry sensitive detection tech n i q u e and it can be coupled to many diffe rent ch ro m at ograp hy systems in on-line operation. The speciation of metals and of o rganometallic compounds has been inve s t i gated for coupling LC and HPLC to ICP-MS utilizing diffe rent sample i n t roduction techniques as to guarantee highest sensitiv i t y...

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