Traceability of trace analysis

Traceability provides the terminology, concepts and strategy for ensuring that analytical chemical measurements are comparable. At present the reference points are often internationally agreed methods; they can also be reference materials. Ideally there should be a single reference point, which in the case of chemistry is the SI Unit the mole but much work will be required to achieve such a situation. Traceability does not imply high accuracy and levels of certainty consistent with fitness for purpose criteria is the goal. This paper discusses the relevance of the concept of traceability and reviews developments leading to a conceptual model for analytical chemistry. It also reports some recent work and considers future needs. (author)