The analytical composition of a @S05471@, expressed in terms of the proportion of a designated solute in a designated solvent, is the solubility of that solute. The solubility may be expressed as a concentration, molality, @A00296@, @M03980@ ratio, etc.
Orange Book, 2nd ed., p. 84 [Terms] [Book]
See also:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2214 [Terms] [Paper]