Centrifugal separator definition

Fig. 1. Separation in a bottle centrifuge, where X is the initial position of a particle (drop). See text for definition of terms.

PURE SUBSTANCES A pure substance is a form of matter with a definite composition and distinct properties. This type of matter can not be separated by ordinary processes like filtering, centrifuging, boiling or melting. 

Since it is preferable to produce definite values for the major parameters, let us say that this coefficient gives a value for A. The coefficient of z1, in equation (7.239), on the other hand, gives us a linear combination of AD and y this is the equation which defines the nature of the indeterminacy between A D and y. If the coefficient of z2 in equation (7.240) can be determined (it is very small in practice), it would appear that y and A D can be separated. In other words, the values of all four parameters in the Hamiltonian can be obtained. However, at this level of approximation, we have also to include the next two terms in the centrifugal expansion of Xso and Xsr (A H and yo) which contribute to the coefficient of z2 as well. Thus only three of the four parameters in equation (7.235) can be determined. We choose these to be B, A and the coefficient of z1 in equation (7.239). In practice, we might choose to constrain y to zero in the fit and then determine an effective value for Au, denoted by Ad - Substitution in equation... 

SOLUBILITY OF PRECIPITATES A large number of reactions employed in qualitative inorganic analysis involve the formation of precipitates. A precipitate is a substance which separates as a solid phase out of the solution. The precipitate may be crystalline or colloidal, and can be removed from the solution by filtration or by centrifuging. A precipitate is formed if the solution becomes oversaturated with the particular substance. The solubility (5) of a precipitate is by definition equal to the molar concentration of the saturated solution. Solubility depends on various circumstances, like temperature, pressure, concentration of other materials in the solution, and on the composition of the solvent. 

By definition, this mode of separation should be called high-speed liquid-fiquid partition chromatography or centrifugal partition chromatography, because only one solvent phase is mobile. In the case of DuCCC, for the two-phase solvents countercrossing each other inside the coiled column from opposite directions, both phases are mobile and there is no stationary phase involved. 

Fig. 6. Kinetics of immobilization of glutaryl-7-ACA-acylase on epoxy-activated polymethacrylate. The Gl-7-ACA-acylase was incubated with the epoxy-activated carrier. At definite times aliquots were taken from the reaction suspension. Supernatant and carrier-fixed enzyme were separated by centrifugation. The carrier-fixed enzyme was washed with water to remove non-covalently linked enzyme. The activities of the immobilized enzyme and supernatant were determined (5 mM potassium phosphate buffer pH 8,37°C, 2% glutaryl-7-amino cepha-losporanic acid, pH-stat 8.0). Simultaneously, an aliquot of carrier-fixed enzyme was boiled in sodium dodecylsulfate (SDS)/glycine buffer and the supernatant was subjected to SDS-polyacrylamide electrophoresis (see insert from left to right lane 1 Carrier-fixed enzyme, 2 h lane 2 Carrier-fixed enzyme, 4 h lane 3 Carrier-fixed enzyme, 6 h lane 4 Carrier-fixed enzyme, 21 h lane 5 Carrier-fixed enzyme, 69 h lane 6 Dialyzed enzyme lane 7 Supernatant, 2 h lane 8 Supernatant, 21 h lane 9 Supernatant, 69 h lane 10 Molecular weight calibration markers)...

The blood samples were centrifuged at 20,000 rpm at a distance of 4.5 inches for 20 minutes in a centrifuge maintained at 20°C. After centrifugation the blood separated into two layers, a top layer of plasma and a bottom layer of red cells. Since the liquid fluorocarbon is immiscible with the blood and is much heavier than the blood, entrainment of fluorocarbon in blood should result in the formation of a small, third layer of the fluorocarbon at the very tip of the pointed centrifuge tubes after such intensive centrifugation. However, no such layer was found in the tubes for all the four blood samples tested. The blood samples were also examined carefully under microscope. No tiny droplets of fluorocarbon were noticed. While it is possible that a few liquid membranes ruptured and escaped detection and more definitive testing would be required before application, instability of the liquid membranes does not seem to be a major problem. 

Definition Insol. proteinaceous material residue after mechanical rupture of yeast cells of Saccharomyces cerevisiae and removal of whole cell walls by centrifugation and separation of sol. cellular materials... 

---