(qualitative): The extent to which other substances interfere with the determination of a substance according to a given procedure.
(quantitative): A term used in conjunction with another substantive (e.g. constant, coefficient, index, factor, number) for the quantitative characterization of interferences.
Source: PAC, 1983, 55, 553. 'Recommendations for the usage of selective, selectivity and related terms in analytical chemistry' on page 555 (https://doi.org/10.1351/pac198855030553)
See also: PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2174 [Terms] [Paper]