extra-column volume

in chromatography
https://doi.org/10.1351/goldbook.E02295
The volume between the effective injection point and the effective detection point, excluding the part of the column containing the stationary phase. It is composed of the volumes of the injector, connecting lines and detector.
Source:
PAC, 1993, 65, 819. (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 832 [Terms] [Paper]