Metrological tools for the reference materials and reference instruments of the NIST material measurement laboratory

Abstract

The National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards, was established by the U.S. Congress in 1901 and charged with establishing a measurement foundation to facilitate U.S. and international commerce. NIST provides reference materials and reference instruments that are used to ensure the accuracy, metrological traceability, and comparability of measurement results in many diverse fields of science, industry, and technology. This document provides and explains the vocabulary used at NIST to define and describe the reference materials and reference instruments available to NIST's customers as well as documenting the methods used in developing these materials. The definitions and descriptions provided supersede those used in the original version of this publication, NIST SP260-136. 1 Scope The NIST Material Measurement Laboratory (MML) serves as the U.S. national reference laboratory for measurements in the chemical, biological, and material sciences. MML activities include the development and dissemination of reference materials and reference instruments to assure the quality of measurement results. While other NIST operating units develop reference materials and reference instruments, MML produces the majority of NIST reference materials and, via its Office of Reference Materials, supports the production and dissemination of ALL of NIST's reference materials and instruments. The definitions and descriptions provided in this document apply to NIST's certified reference materials (CRMs) and reference instruments issued after the publication of this document.

Certification of Standard Reference Material® 955d, Toxic Elements and Metabolites in Frozen Human Blood

“…Certified Values: A NIST certified value is a value for which NIST has the highest confidence in its accuracy in that all known or suspected sources of bias have been fully investigated or accounted for [14].…”

“…A reference value is a noncertified value that is the best estimate of the true value where all known or suspected sources of bias have not been fully investigated by NIST [14]. The densities of the three levels of SRM 955d were measured using an Anton Paar DMA 5000 M Density Meter.…”

“…The densities of the three levels of the SRM are summarized in Table 38. Information Value: An information value is a non-certified value that is considered to be of interest to the SRM user, but insufficient information is available to assess the uncertainty associated with the value, or only a limited number of analyses were performed [14]. To support the applications in dried blood spot (DBS) testing of metabolites, thyroglobulin (Tg) in SRM 955d Level 1 was measured by the collaborating laboratory at the Human Nutrition Laboratory, Institute of Food Nutrition and Health, Swiss Federal Institute of Technology (ETH) in Switzerland.…”

Evaluating, Expressing, and Propagating Measurement Uncertainty for NIST Reference Materials

“…The term "certi cate" is used throughout as shorthand for the document that accompanies each reference material produced by NIST, regardless of whether the values assigned to the material properties are certi ed or non-certi ed. Similarly, the term "reference material" encompasses all types of reference materials, and the term "reference value" likewise means any value assigned to a material property in a manner that satis es the requirements speci ed by Beauchamp et al [2020].…”

A Python-Based Pipeline for Preprocessing LC–MS Data for Untargeted Metabolomics Workflows

“…Different types of QC samples, i.e., system suitability samples, process blanks, pooled/intrastudy QC samples, process internal standards, and intralaboratory QC samples such as reference materials, allow the assessment of data quality within a study [ 6 , 19 , 20 ]. In particular, certified reference materials (CRMs) are commercially available standards that are used for accuracy control, method validation, and/or International System of Units traceability, while reference materials (RMs) (with non-certified values) are standards utilized for method harmonization and/or quality assessment [ 21 ]. RMs also allow data quality comparisons across different studies within a laboratory and across different laboratories and can, therefore, be used as interlaboratory QC samples [ 19 , 20 , 22 ].…”