Packing procedure, column

One question of chief interest concerns the number of runs that can be run with one individual SEC column. The lifetime of the sorbent itself must be tested as well as the maximum run number for the packed column. Because column packing procedures for SEC columns are rather time-consuming and all SEC columns have to be checked very carefully with respect to performance, very frequent repacking of the column is unreasonable. Therefore, CIP protocols are generally necessary. The CIP protocol should be developed as part of the process validation program. 

Unger, K.K. (editor)(1979). Silica columns packing procedure and performance characteristics. Porous Silica Journal of Chromatography Library, Volume 16. Elsevier, Amsterdam. pp.169 186. 

Ctriunm ovetloading, 52 Column packing procedure, 125, 145,146 apparatus, 146-148... 

Under constant pattern conditions the LUB is independent of column length although, of course, it depends on other process variables. The procedure is therefore to determine the LUB in a small laboratory or pilot-scale column packed with the same adsorbent and operated under the same flow conditions. The length of column needed can then be found simply by adding the LUB to the length calculated from equiUbrium considerations, assuming a shock concentration front. 

It appears that the equation introduced by Van Deemter is still the simplest and the most reliable for use in general column design. Nevertheless, all the equations helped to further understand the processes that occur in the column. In particular, in addition to describing dispersion, the Kennedy and Knox equation can also be employed to assess the efficiency of the packing procedure used in the preparation of a chromatography column. 

It is a common procedure to assume certain conditions for the chromatographic system and operating conditions and, as a result, simplify equations (20) and (21). However, in many cases the assumptions can easily be over-optimistic, to say the least. It is necessary, therefore, to carefully consider the conditions that may allow such simplifying procedures and take steps to ensure that such conditions are carefully met when such expressions are used in practice. Now, the relative magnitudes of the resistance to mass transfer terms will vary with the type of columns (packed or capillary), the type of chromatography (GC or LC) and the type of particle, i.e., porous or microporous (diatomaceous support or silica gel). 

The uncomplicated packing procedure of traditional media to yield efficient columns is demonstrated by the reduced plate heights of 2 or slightly below as reported for Sephadex and for the qualification of Sepharose columns for the determination of MWDs. 

Mount the upper adaptor, thereby compressing the gel bed, until the filter plate reaches the height of the column end piece. The lower adaptor should be adjusted before starting the packing procedure in order to reach 600 10 mm total bed height. 

PSS has developed proprietary packing procedures for its sorbents, that allow a homogeneous filling of the column hardware with no change in particle properties. This thoroughness in the packing procedure is reflected in the superior performance of PSS SEC columns and their long life, even in difficult conditions. 

The procedure chosen for column packing depends chiefly on the mechanical strength of the packing and its particle size. Particles of diameter > 20 jum can usually be dry-packed, whereas for particles with diameters <20 /xm slurry... 

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