spreading function

in chromatography
https://doi.org/10.1351/goldbook.S05892
The normalized signal produced, as a function of elution volume at the outlet of a size-exclusion chromatography set-up, by an instantaneous injection of a uniform sample.
Source:
Purple Book, 1st ed., p. 69 (http://old.iupac.org/publications/books/author/metanomski.html)