1. General remarks:

	Properly packed columns:  the bed is uniform and tight throughout the entire column volume.
	Under-packed columns:  loose bed settles with time or under pressure leaving voids behind.  Uniform settling (flat bed surface detached from the frit) results in band broadening due to the  "smiling" effect.  Non-uniform settling (channels) results in early "break-through" and severe "tailing".
	Over-packed columns:  areas of compressed soft beads restrict the flow and result in "peak tailing".  Over time, the packing density equalizes throughout the entire column. Such bed relaxation can occur  by itself and/or is assisted by pumping and other vibration.
	"Breathing bed":  reversible 1-5% volume change of the bed, e.g. ion-exchanger under the extremes of pH/salt condition.  Bed contraction can produce channeling and/or "smiling".  Bed expansion can over-pressure or even burst the column (e.g. when a  soft Q-exchanger is treated with NaOH followed by pure H2O, ref:  Donnan equilibrium).  In most cases, a proper choice of  running/cleaning conditions and a proper selection of the packing media prevents this problem.
	Biseps, Inc. recommends packing procedures for our SPC hardware that are generally applicable to any sorbent slurry.  However, optimal parameters (slurry concentration, pressure, flow, solvent, etc.) can differ from one sorbent to another.  Therefore, we suggest to consult with particular sorbent  manufacturer for specific packing protocols.

#2. Packing small SPC  

#3. Packing Prep SPC 

#4.

4.1. Spikes. One way to evaluate/validate packing quality is to inject spikes into the column at about 1-2 % of the Column Volume.  Normally, acetone (1% solution in the buffer) or a salt (NaCl, 0.1-M) is used.

4.2. In-Process Methods.  These non-intrusive methods are based on the frontal shape of the salt/pH concentration shifts during the process, such as during elution, or washing, or cleaning steps.  However, ascending salt gradients under certain conditions might produce up to 100-X larger HETP values than the descending one (Hans P. Lettner, Oliver kaltenbrunner, and Alois Jungbauer, "HETP in Process Ion-Exchange Chromatography", J. Chrom. Sci. 33 (1995)).  Therefore, any "in-process" method  must be thoroughly validated  under specific in-process conditions using the spike method.