A small
radioactive source containing
3H
or
63Ni
ionizes the molecules of the
carrier gas (nitrogen or argon–methane), and a potential difference creates a small current.
This current is reduced when an electronegative substance (such as a halocarbon) is
introduced. The reduction in current is a measure of the concentration of the electronegative
substance. The
detection limit (threshold) varies greatly according to the substances to be analysed and can reach
a mixing ratio of
. The linear dynamic range may be
but the maximum measuring value generally lies below
.
Source:
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2191
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
