An individual portion of material collected by a single operation of a sampling device. Increments may be reduced individually or tested either (a) individually or (b) combined with other increments with the resulting composite
reduced in size and tested as a single unit. Increments are created by the sampling operation and are usually taken from parts of a lot separated in time or space. Increments of a bulk population correspond to units of a packaged population.
PAC, 1990, 62, 1193
(Nomenclature for sampling in analytical chemistry (Recommendations 1990))
on page 1205
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook