H. A. Sober

Bio: H. A. Sober is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Elution. The author has an hindex of 1, co-authored 1 publications receiving 198 citations.

Variable Gradient Device for Chromatography

Abstract: Publisher Summary This chapter discusses variable gradient device for chromatography. Since the introduction of gradient elution to chromatography several years ago, there have been many applications of the general technique in the fractionation of mixtures of substances having a wide range of elution requirements. In such cases, the use of a gradient greatly facilitates the operational aspects of chromatography, as it automatically encompasses these requirements. Moreover, in the case of substances that have a tendency to be eluted in broad, tailing bands when a single solvent is used, gradient elution provides a means of sharpening the peaks without introducing the artifacts that can result when stepwise changes in eluting agents are made. Several methods for the production of gradients have appeared in the literature. With the exception of those that can utilize differential pumping rates, all require a change in apparatus for each change in the shape of the gradient.

[1] Column chromatography of proteins: Substituted celluloses

Abstract: Publisher Summary Chromatography of proteins on cellulose ion exchangers involves primarily the establishment of multiple electrostatic bonds between charged sites on the surface of the adsorbent and sites bearing the opposite charge on the surface of the protein molecule. The number of such bonds that can be established determines the concentration of competing ions required for the release of the bound molecule. Thus, proteins differing significantly in charge density, or in number of charges by virtue of size, may be expected to differ in their requirements for elution. Charge distribution can also be regarded as a factor. But it is the total effect of these factors that determines the affinity of the protein for the adsorbent, so a simple relation between any one of them and the chromatographic behavior of the protein in question is not always obtain. The situation is further modified by the possibility that in some cases nonelectrostatic forces might play an important role.