Column Dead Time as a Diagnostic Tool

摘要

Often considered a necessary evil, the first peak in a chromatogram can be a useful diagnostic tool for troubleshooting liquid chromatographic (LC) separations. Most people I encounter refer to this as the column dead time peak, abbreviated t_0 However, it has a wide variety of other names: junk peak, garbage peak, solvent front, or hold-up time, with t_M as the most common alternative abbreviation. This represents the time it takes something to go through the LC column that does not interact with the column. A corresponding dead volume (or hold-up volume), V_M, is the volume of mobile phase inside the column. This volume comprises both the volume of mobile phase between the packing particles (the interstitial volume) and the volume within the particles (the pore volume). We'll see that t_0 can be a useful diagnostic tool to identify potential problems with an LC method.