Packed columns applications

J.L. Janicot, M. Caude, and R. Rosset, Separation of opium alkaloids by carbon dioxide sub- and supercritical fluid chromatography with packed columns Application to the quantitative analysis of poppy straw extracts, J. Chromatogr., 437 351 (1988). 

As with any form of chromatography, the separating efficiency of capillary columns in gas chromatography is strongly dependent on the column stationary phase, carrier gas flow rate, and temperature. Because of the high separation efficiency of capillary columns, only a limited number of stationary phases can be substituted for the numerous phases used in most packed column applications. The choice of a stationary phase is commonly dictated by experience. A phase that has been successfully used by others is usually a good choice. Fre-... 

Dispersed phase loadings should not exceed 25 gal/min-ft For most packed column applications, the maximum dispersed phase loadings will range 10 to 20gal/min-ft. Dispersion is best accomplished with perforated plates with a hole size range of 3/16 to 1/4 in. Velocities though the holes should not exceed 0.8ft/s, but if short riser tubes are employed, the velocities can be as high as 1.5 ft/s. 

Common packed column applications of porous polymers... 

Figure 5.13, Representative flow ceUs used for absorption detection. A, Z-cell for conventional packed column applications and B, a low-volume fiber optic ceU (volume = 4 nl and path length 0.15 mm) for use with packed capillary columns.

Today, most applications are based on packed columns at relatively low temperatures with binary and ternary mobile phases. It has become clear that the characteristics of interest are not limited to supercritical conditions. Most packed column applications actually use conditions just below the critical temperature, but well above the critical pressure of the mixed fluids, i.e., subcritical (in other words, liquid ). Unlike many observers expectations, important characteristics such as diffusion coefficients and viscosity are virtually identical whether the conditions are just supercritical or just subcritical. 

Anonymous, Packed Column Application Guide, Bulletin 890, Supelco, Bellefonte, PA, 1995. 

HPLC genetically, meaning high performance or high pressure liquid chromatography. Ipotensic GC is capillary based packed-column applications are rare. 

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