ISO Guide 33 has just been updated. The new 3rd Edition, titled “Reference materials – Good practice in using reference materials,” not only cancels and replaces the 2nd Edition but also the now-obsolete ISO Guide 32, “Calibration in analytical chemistry and use of certified reference materials.” Along with the new 3rd Edition of the ISO Guide 30, “Reference materials – Selected terms and definitions,” the document provides users with new definitions of RM (Reference Material) and CRM (Certified Reference Material). This has a technical impact on the Guides that users will want to keep up with.
REMCO, the ISO committee on Reference Material that develops these Guides, introduced the new definitions to incorporate the concepts of both quantitative and qualitative analysis. While the Guides 30 and 33 now are harmonized with the new terminology, ISO/IEC Guide 99 and JCGM-200 still need to be re-written with the new concepts in mind.
If you’re unfamiliar with the use of Reference Materials, they’ve been developed to use in testing. They form a kind of “bench-mark” for calibration of equipment, allowing for a standardized level of acceptance that the testing samples can then be measured against.
As with any standardized concept or material, the use of a consistent set of terms and definitions is essential. And a strict methodology for handling any physical items involved in testing is essential to providing consistent and valid test results.
ISO Guide 33 is broad in scope, covering many essential concepts and practices for those using RMs and CRMs. The document not only starts with the usual scope, reference documents, and definitions sections, it also includes a clause on symbols and another on conventions. Then it moves into the main topic with a clause on RMs and their role in measurement. Next you’ll learn the proper way to handle RMs and CRMs, how to assess the precision, and the use of bias assessment. The last four clauses cover calibration, assigning values to other materials, conventional scales and the selection of CRMs and RMs. Three Annexes follow, with information on key characteristics of RM’s with respect to the applications, calibration models (as well as associated uncertainty models), and decision errors. A 24-item bibliography finishes up the publication.
ISO Guide 33 and ISO Guide 30 (which provides definitions for the terms used for RMs) are essential for any testing lab that calibrates using these methods. If you’re using the older editions, get your copies of the new releases now. You can order online at the Document Center webstore, www.document-center.com. Or contact our staff by phone (650-591-7600), fax (650-591-7617) or email (info@document-center.com). We’ve been working with standards since 1982. Make us your Standards Experts!
