Displacement chromatography gradient elution

New concepts presented in this edition include monolithic columns, bonded stationary phases, micro-HPLC, two-dimensional comprehensive liquid chromatography, gradient elution mode, and capillary electromigration techniques. The book also discusses LC-MS interfaces, nonlinear chromatography, displacement chromatography of peptides and proteins, field-flow fractionation, retention models for ions, and polymer HPLC. 

Hodges, R. S., Burke, T. W. L., and Mant, C. T. (1988). Preparative purification of peptides by reversed phase chromatography—sample displacement versus gradient elution modes. ]. Chromatogr. 444, 349-362. 

Malmquist, G. and Lundell, N., Characterization of the influence of displacing salts on retention in gradient-elution ion-exchange chromatography of peptides and proteins, J. Chromatogr., 627, 107, 1992. 

For the implementation of techniques such as step-elution, gradient-elution, displacement-elution, as well as for the wash and sanitation steps needed for ion exchange chromatography and continuous downstream processing in general. 

FIGURE 9 Displacement chromatography on a retained pH gradient. The presaturation and elution buffers are formed by titrating 0.05 M NaOH with MOPS and acetic acid, respectively. Adsorbent TosoHaas TSK Q-5PW (5 /x particles) flow rate 0.1 mL/min proteins /3-lactoglobulins A and B (from Narahari et a/.,69 with permission from Elsevier Science). 

In gradient elution or in displacement chromatography, the boxmdary condition given by Eq. 2.7 still applies to the sample components. However, the mobile phase contains an additive at a concentration which varies during the experiment. This additive is the strong solvent in gradient elution and the displacer in displacement chromatography. 

Melittin, the main component of bee venom, was analyzed by gradient elution (Figure 12.22a) and purified by displacement chromatography (Figure 12.22b) on micropellicular CIS silica [50]. An isotachic train at two different temperatures is shown. Note that the flow rate on the 30x4.6 mm analytical column was 3 mL/min, while on the 105x4.6 mm displacement column best results were obtained at only 0.6 mL/min, in spite of the fast mass transfer kinetics on pellicular sorbents [50]. 

The set of equations 15.34 and 15.35, along with the equilibrium isotherms given by Eqs. 15.36,15.37, and 15.39 for the two compoimds was solved by the method of characteristics, using a method previously developed and apphed to nonlinear isocratic elution, gradient elution and displacement chromatography [41,42]. 

Comparison Between Isocratic Elution, Gradient Elution and Displacement Chromatography. 912... 

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