Fixed elution operation

In the case of fixed-bed operations (elution chromatography, SMB, etc.), if the column is simulated to a series of mixed cells, the mass balance equation of a component i over a plate k is... 

Figure 1 illustrates the two basic methods of fixed-bed operation. In saturation, the solute undergoing adsorption is removed continually from the carrier liquid or gas, and accumulates in the solid phase. Such transfer can continue until the concentration on the solid reaches a value corresponding to equilibrium with the concentration in the feed stream, and the column effluent reaches the feed concentration. When the column is saturated to the extent that breakthrough of the solute occurs, the flow is interrupted, and the column is then regenerated or eluted by pass-... 

Fig. 23. PDC-spreading surface D = K(V, V) from Section 4 (taken as kernel of an integral operator in Sect. 5), calculated from Eqs. (44a) (with V = VD(P) from Fig. 22 a) and (46) (with a (P), yD(P) and 8d(P) from Fig. 22b). Axis V = VD(P) (in cm3) specifies nearly the maximum of the section of a plane V = const with the spreading surface D for a fixed degree of polymerization predicted by the calibration curve of the column this section represents a monodisperse PDC-eluogram, in which VD is computed according to the first equation of system (45 a). Axis V (in cm3) specifies any elution volume in this section (monodisperse elution curve) as a result of the axial dispersion (spreading) in the PDC-column 31 for this P. Practically monodisperse eluograms are obtained in PDC at 28 °C (to which Fig. 22a-b is related) because the resolution of the column can be neglected m this range. The axonometric plot of the spreading surface D was drawn by a computer CDC-3300...

Combined ion exchange and liquid-liquid extraction processes produce an oxide which is pure enough to be a direct source of nuclear grade metal. A later development (Porter-Arden) involved transferring resins between loading and elution stations which simulated a more efficient countercurrent operation but was not truly continuous. Fixed bed designs must employ a clarified feed if not to... 

There are six modes of HPLC currently in use for secondary metabolite analysis, namely, HP-RPC, HP-NPC, HP-IEX, HP-HILIC, HP-SEC, and HP-AC. The principles of these different modes are explained below. All of these various chromatographic modes can be operated under isocratic (i.e., fixed eluent composition), step gradient, or gradient elution conditions (variable step or continuous changes in eluent composition), except for SEC, which is usually performed under isocratic conditions. All modes can be used in analytical, semipreparative,8 or preparative9-14 situations. 

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