selectivity

in analysis
  1. (qualitative): The extent to which other substances interfere with the determination of a substance according to a given procedure.
  2. (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
See also:
PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2174