Sense traceability

Traceability has recently become more prominent among the concepts used by analytical chemists to characterize quality of measurement. It is the chain of comparisons from the measurement back to a standard of some kind, by reference to which we can estimate the uncertainty of the result. In physical metrology the SI unit is usually the end-point of traceability. An SI end-point for traceability can also be postulated for chemical measurements of concentration, i.e., that chemical measurements should be traceable to the kilogramme or, wherever possible, to the unit of 'amount of matter', the mole. The present paper argues against this view, maintaining the position that most chemical measurements are traceable neither to the mole nor the kilogramme, but simply to the material used for calibration and (sometimes) to the analytical method.