Packing method for coupled macrobore liquid chromatography columns

The Column in Liquid Chromatography

“…The particles have to enter the column at high velocity in order to overcome frictional forces from viscous flow around the particles and at the wall. In this case, upward conventional column diameters, and fairly large microparticles (8-10 micrometers) by using a prepacked column as a restrictor down stream from the empty column blank to be packed [159]. The wall effect should become more important the greater the column length to internal diameter ratio and minimized by using columns with smooth walls.…”

“…Using Figure 4.8 as a guide, the down-fill slurry column packing procedure will be described [140,147,149,[158][159][160][161][162][165][166][167][168]. A retaining porous frit or screen and standard Swagelok fitting are attached to the lower end of the precleaned column blank.…”

Fundamental Relationships of Chromatography

“…This depends on the particle size and the packing technique but is not much greater than the largest dimension for each particle size given in Table 1.14 for conventional and small bore columns. This is no longer accepted as true although from recent studies it is obvious that not just any group of columns can be connected together with additive efficiency [231][232][233][234], The individual columns to be concatenated must be efficient, have similar efficiencies and stable packing structures and must not exhibit significant asymmetry for eluted peaks. Early reports indicated that conventional bore columns could not be coupled into longer lengths with additive efficiency [230].…”

“…Early reports indicated that conventional bore columns could not be coupled into longer lengths with additive efficiency [230]. Halasz predicted that a 6.7 meter column packed with 8 micrometer particles operated at about 400 atmospheres would deliver about 400,000 theoretical plates with a holdup time of about 1 hour [232] . Good columns and moderate columns when coupled together lead to results that are far from additive most probably due to the heterogeneous permeability of the coupled columns which results in an exaggerated multipath term increasing in importance as the column length is increased.…”

“…For long columns operated at high pressures and short, small particle columns operated at high flow rates a considerable amount of heat is generated due to frictional heating of the mobile phase during its passage through the column [217,218,[232][233][234][235][236]. Heat is generated at a constant rate over the whole length of the column.…”