The amount of the material of interest divided by the total amount of substances in
the volume of interest. Concentration may be defined in terms of numbers of atoms
or in terms of weight().
PAC, 1979, 51, 2243
(General aspects of trace analytical methods - IV. Recommendations for nomenclature,
standard procedures and reporting of experimental data for surface analysis techniques)
on page 2246
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