retention time of an unretained compound

in size-exclusion chromatography
https://doi.org/10.1351/goldbook.10040
Retention time of a sample component the molecules of which are larger than the largest pores of the particles of the stationary phase.
Notes:
  1. This component will be eluted first from the column.
  2. The retention time of an unretained compound is related to the retention volume of an unretained compound (in size-exclusion chromatography) and the flow rate (\(F_{\rm{c}}\)) by \(t_{0} = V_{0}/F_{\rm{c}}\)
Source:
PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 212 (https://doi.org/10.1515/pac-2017-0111)