Comparability and Traceability in Analytical Measurements and Reference Materials†

The present paper argues that, in many sectors of analytical chemistry, measurements are not and need not be traceable to the kilogramme or the mole. Instead comparability among rational methods is assured by a traceability to the pure analyte. This leads to a system that gives the appropriate metrological level to reference materials. The argument is addressed to geochemists but is of general applicability.