학술논문
A dynamic gravimetric standard for trace water.
Document Type
Article
Source
Subject
*GRAVIMETRIC analysis
*PHYSICAL measurements
*DILUTION
*UNCERTAINTY (Information theory)
*ATMOSPHERIC water vapor
*MASS (Physics)
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Language
ISSN
0034-6748
Abstract
A system for generating traceable reference standards of water vapor at trace levels between 5 and 2000 nmol/mol has been developed. It can provide different amount fractions of trace water vapor by using continuous accurate measurements of mass loss from a permeation device coupled with a dilution system based on an array of critical flow orifices. An estimated relative expanded uncertainty of ±2% has been achieved for most amount fractions generated. The system has been used in an international comparison and demonstrates excellent comparability with National Metrology Institutes maintaining standards of water vapor in this range using other methods. [ABSTRACT FROM AUTHOR]