test portion

Synonym: analytical portion

The amount or volume of the test sample taken for analysis, usually of known weight or volume.
Source:
PAC, 1989, 61, 1657 (Nomenclature for automated and mechanised analysis (Recommendations 1989)) on page 1660
See also:
PAC, 1990, 62, 1193 (Nomenclature for sampling in analytical chemistry (Recommendations 1990)) on page 1206