The understanding of the functions of trace elements in metabolism, whether associated with microorganisms, plants or animals, has advanced considerably during the last twenty years. There are two main aspects of the importance of trace elements in biological materials: first, their toxic effects and secondly, the essential nature of some of the elements for normal growth and health. Research in trace elements and their essential role in biological processes has advanced through several stages, necessitating more and more effective methods of determination. Despite the marked improvements in methods of trace analysis during these twenty years, the ever increasing need for higher sensitivity to meet new demands has meant the greater need, not only for improving the limits of detection, but also for new standard reference materials, better sampling, better sample handling and better design of trace and ultra-trace analysis laboratories. This book focusses on all areas of trace element determination with detailed discussion on all major methods of analysis. Additionally, the determination of concentrations of major toxic and essential trace elements is discussed at length.