The determination of iodine species in environmental and biological samples (Technical report)

Iodine is found in organic forms in plants and animals and in inorganic for ms in natural water samples. Methods of identification and quantitative det ermination for iodine species are decided by the types of compound and the matrices in which they occur. Iodine is an essential element and specific r adioimmunoassay methods have been devised for physiologically important com pounds (thyroxine and related compounds) in which it is found. In addition, marine plants and animals have provided a rich source of varied and unexpe cted organic iodine compounds that occur, along with other organic halogen compounds, as secondary metabolites. Natural waters, particularly marine wa ters contain iodine chiefly in the forms of iodide and iodate. Organic iodi ne compounds in biological samples have been identified by classical natura l products chemical techniques following their isolation, and by modern spe ctroscopic methods. Routine analysis of such compounds can be done by gas c hromatography (GC) and high performance liquid chromatography (HPLC). Analy sis of inorganic iodine species in waters is carried out by catalytic, elec trochemical and spectrometric methods and by GC; possibly HPLC inductively coupled-mass spectrometry (ICP-MS) might be the method of choice in the fut ure.