Trace elements in clinical samples revisited—speciation is knocking at the door. Sample preparation, separation of the species and measurements methods

The measurement of the different species of the trace elements in clinical samples requires a sample preparation and handling that is specially designed for that purpose. The present article is an attempt to give background information about the various procedures. Some of the difficulties that may affect the separation and the stability of the species will be highlighted with practical examples. The intent is not to present a review of the existing knowledge about all the different species of the trace elements, neither to give procedural details in various biological fluids and tissues, but rather to initiate the reader who wants to start research on this topic.