exclusion limit - in SEC, the upper limit of molecular weight (or size), beyond which molecules will elute at the same retention volume, called the exclusion volume. Many SEC packings are referred to by their exclusion limit.
exclusion volume (Ve) - the retention volume at which all molecules with MW more than exclusion limit elute together.
external standard - quantitative analysis method in chromatography where dilutions of pure standard are compared to unknown samples; the standards are the components of interest.
extracolumn effects - the band broadening effects of parts of the chromatographic system outside of the column itself. Extracolumn effects must be minimized in order to maintain the efficiency of the column. Areas of band broadening can include the injector, connecting tubing, endfittings, frits, detector cell volume, and internal detector tubing. The variances of all of these contributions are additive.