Wikipedia - Aliquot (Chemie) (de) Wikipedia - Sample (material) (en) aliquot

in analytical chemistry
https://doi.org/10.1351/goldbook.A00218
A known amount of a homogeneous material, assumed to be taken with negligible @S05463@. The term is usually applied to fluids. The term 'aliquot' is usually used when the fractional part is an exact divisor of the whole; the term 'aliquant' has been used when the fractional part is not an exact divisor of the whole (e.g. a $$15\ \text{ml}$$ portion is an aliquant of $$100\ \text{ml}$$). When a @L03433@ or @T06285@ is 'aliquoted' or otherwise subdivided, the portions have been called split samples.
Sources:
PAC, 1990, 62, 1193. (Nomenclature for sampling in analytical chemistry (Recommendations 1990)) on page 1206 [Terms] [Paper]
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2173 [Terms] [Paper]