Amount of substance

News and Updates

Better Flowmeters with the Big Blue Ball

February 24, 2017

Last year, upwards of 25 trillion cubic feet of natural gas were delivered to customers in the United States, and when...

How Sweet It Is: NIST Metrology and the Maple Syrup Industry

January 04, 2017

NIST is frequently asked to provide unusual, sometimes downright exotic, measurements and calibrations in support of U...

Redefining the SI Base Units

November 02, 2011

Note: Much more recent information is available about redefinition of the SI units. For a comprehensive general...

'Sí' on the New SI: NIST Backs Proposal for a Revamped System of Measurement Units

October 26, 2010

Taking the first steps of what would be a major historical advance in the science of measurement, the National...

Publications

Metrology for stable isotope reference materials: 13C/12C and 18O/16O isotope ratio value assignment of pure carbon dioxide gas samples on the Vienna PeeDee Belmnite-CO2 scale using dual-inlet mass spectrometry

May 25, 2018

Author(s):

Abneesh Srivastava, R M. Verkouteren

Isotope ratio measurements have been conducted on a series of isotopically distinct pure CO2 gas samples using the technique of dual-inlet isotope ratio mass...

Evaluating droplet digital PCR for the quantification of human genomic DNA: converting copies per nanoliter to nanograms nuclear DNA per microliter

February 22, 2018

Author(s):

David L. Duewer, Margaret C. Kline, Erica L. Romsos, Blaza Toman

The highly multiplexed polymerase chain reaction (PCR) assays used for forensic human identification perform best when used with an accurately determined...

Correction of an adding-doubling inversion algorithm for the measurement of the optical parameters of turbid media

January 01, 2018

Author(s):

Paul Lemaillet, Catherine C. Cooksey, Jeeseong Hwang, Heidrun Wabnitz, Dirk Grosenick, Lin Yang, David W. Allen

We present broadband measurements of the optical properties of tissue-mimicking solid phantoms using a single integrating sphere to measure the hemispherical...

Certification of Standard Reference Material® 968f Fat-Soluble Vitamins in Frozen Human Serum

December 14, 2017

Author(s):

Jeanice M. Brown Thomas, David L. Duewer, Carolyn Q. Burdette, Lorna T. Sniegoski, James H. Yen

Standard Reference Material (SRM) 968f is intended for use in validating methods for determining fat soluble vitamins in human serum and plasma and value...

Projects & Programs

NIST PS1 Primary Standard for quantitative NMR (Benzoic Acid)

The "first-of-its-kind" in an entirely new class of reference material, NIST PS1 Primary Standard for quantitative NMR (Benzoic Acid) is now available! The PS...

Advanced Ambient Mass Spectrometry, Secondary Ion Mass Spectrometry and Ion Mobility Spectrometry

The Surface and Trace Chemical Analysis Group (STCAG) conducts both applied and fundamental research into the development, characterization, and analysis of...

International Comparisons for Chemical Measurements

Because of NIST's role as the National Metrology Institute (NMI) in the U.S., the Chemical Sciences Division's measurement capabilities must be benchmarked...

Tools & Instruments

Local Electrode Atom Probe Tomography (LEAP)

Field evaporates (with a voltage and laser pulse) a sharp tip-shaped specimen. Collects the ionization products in a position-sensitive, time-of-flight mass...

Material Analysis Using Neutron Depth Profiling

Light elements such as helium, lithium, boron, and nitrogen are essential constituents in materials that enable energy technologies; lithium ion batteries,...