Protocols for traceability in chemical analysis

 In continuing their attempt to bring general issues concerned with trustworthy chemical measurements to review and international discussion, the authors propose basic aims and requirements for protocols of chemical-measurement procedures with traceability to the SI or, where this is not possible, to units of internationally recognized measurement scales. Documents describing such protocols could be useful in science, technology, law, or trade. Concepts and definitions for protocols have been introduced in Part I of this contribution. Part II here deals with the development and application of protocols for intended in-laboratory, commercial, national, or international recognition. Protocols deal with measurement methods, instrumentation, and the estimation of uncertainties from all possible sources of measurement errors. Uncertainties define the quality of all links in a traceability chain starting from the value of a measurand in a sample, often through a certified value in a reference material, either to the SI, or – if this is not possible – to a value on a suitable, internationally agreed measurement scale. A protocol may concern itself with the complex interplay between uncertainties, tolerances, and any limit values introduced by the set aims of specific measurements. Received: 23 April 1997 Accepted: 27 April 1997