1. Definition. The benefits of speciation analysis

It is now recognized that measuring total concentrations of an element is no longer sufficient to provide accurate information on its fate in the environment, or in human or animal physiology. In fact, trace elements can exist in different chemical forms, each of which has a different toxicity, mobility or reactivity; examples of these chemical forms are given in table 1 .

These chemical species can be classified into three families. The first group is made up of elements that can present different oxidation states; the best-known example is chromium, which exists in the form of trivalent chromium, a species essential to life, and hexavalent chromium, which is considered a carcinogen [1]. Because of the great difference in toxicity between the two chemical forms of chromium, many European regulations take...