Studies on the Efficiencies of Packed Gas Chromatographic Columns.

Solid Support Characteristics and Plate Height in Gas Chromatography.

“…In the derivation of the van Deemter equation, finite rate of mass transfer in the gas phase was omitted because estimates indicated that its contribution would be negligible compared to that of the liquid phase. or less than dp have been found by many workers (1,7,8,15,32,33,45,56) while others have apparently found negative A values (7,33,52,60). Some evidence has been presented that indicates that A is velocity dependent (7,35,60).…”

“…Bohemen and Purnell (6), Perrett and Purnell (5#), and Kieselbach (46) have data, found by graphical and numeri cal procedures, respectively, that B is relatively independent of liquid load while De Ford et al (15) showed increases in B as liquid load decreased. The B terms for porous supports were considerably less than those for solid glass beads (Norem (56)) and this was attributed to gas hold-up inside the particle.…”

Flow of Ideal Gas

“…To avoid these difficulties, several workers [14,[24][25][26][27] used the product p u as a single pneumatic variable in evaluation of a column performance. Unfortunately, quantity u as a metric of the gas flow has several substantial shortcomings.…”

Solid support characteristics and plate height in gas chromatography

“…Not until 1952 was the idea of gas chromatography investigated by James and Martin (40) who separated volatile fatty acids on a column of kieselguhr impregnated with silicone oil with nitrogen as the eluting gas. or less than dp have been found by many workers (1,7,8,15,32,33,45,56) while others have apparently found negative A values (7,33,52,60). Some evidence has been presented that indicates that A is velocity dependent (7,35,60).…”

“…Bohemen and Purnell (5) found B increased while dp decreased. Bohemen and Purnell (6), Perrett and Purnell (5#), and Kieselbach (46) have data, found by graphical and numeri cal procedures, respectively, that B is relatively independent of liquid load while De Ford et al (15) showed increases in B as liquid load decreased. The B terms for porous supports were considerably less than those for solid glass beads (Norem (56)) and this was attributed to gas hold-up inside the particle.…”