Postcolumn void volume.
Post column dead volumes are the most critical part of a nanoflow system. In most set-ups, dispersion occurs in an improper connection or a not well designed ESI emitter. Peak broadening increases rapidly in low flow, small ID columns (see below). Example. Volumes of peaks leaving the column in a width of 3 sec (FWHM) are typically 3, 12 and 25 nL on a 25, 50 and 75 umID column, resp. When connected to an emitter with a dead volume of e.g 60 nL, the 3 sec wide bands broaden by 20, 6 and 2.6 times, and are observed in width's of 60, 18 and 8 s, resp. (see for more details peak broadening)