Milestones in biological trace element research.

Over 100 years ago, macro-scale analytical techniques were used to discover the roles of special compounds (especially of metallic elements) in living organisms, and investigations were focussed on selected proteins and pigments suspected of containing percentage quantities of metals. In contrast, present-day analytical techniques are capable of detecting extremely small quantities and have become routine ultra-trace measurement tools to probe elemental interactions at cellular levels. The scientific achievements connecting these two boundaries are punctuated with an array of analytical developments; some highlighting the phenomenal advances in the measurement technology and others reflecting the exceptional bioanalytical perception and the multi-disciplinary outlook of trace element investigators. An account of the events that contributed to the overall progress in biological trace element research is the essence of this communication.