Abstract
There is substantial evidence of the complexity of belenium speciation in living organisms and of the importance of the selective determination of the particular species of this element in order to understand its metabolism and biological significance in clinical chemistry, biology, toxicology, and nutrition. The state-of-the-art of analytical techniques available for this purpose is critically evaluated with particular emphasis on the element-selective detection and identification of the detected selenium compounds. Whereas there are a number of techniques available, which can detect various selenium species in living organisms selectively, few techniques exist that are able to identify and to characterize the species detected.