The solution prepared from the test portion for the analytical procedure. The proportions of test portion and solvent are normally known.
PAC, 1989, 61, 1657. 'Nomenclature for automated and mechanised analysis (Recommendations 1989)' on page 1660 (https://doi.org/10.1351/pac198961091657)
PAC, 1990, 62, 1193. 'Nomenclature for sampling in analytical chemistry (Recommendations 1990)' on page 1206 (https://doi.org/10.1351/pac199062061193)