Bulk Preparations

As with the fullerenes, further detailed studies will depend on the discovery of viable bulk preparations of the met-cars. Macroscopic... 

If both steps are kinetically distinct, measurement of gas evolution (D) does not give any information concerning the rate of the subsequent interaction (formation of C). If E is produced in a finely divided state, it may be appreciably more reactive than alternative bulk preparations of the... 

Moving-boundary electrophoretic techniques, originally demonstrated by Tiselius in 1937, employ a U-tube with the sample occupying the lower part of the U and the two limbs being carefully filled with a buffered electrolyte so as to maintain sharp boundaries with the sample. Electrodes are immersed in the electrolyte and direct current passed between them. The rate of migration of the sample in the electric field is measured by observing the movement of the boundary as a function of time. For colourless samples, differences in refractive index may be used to detect the boundary. Such moving-boundary techniques are used mainly in either studies of the physical characteristics of molecules or bulk preparative processes. 

The prepared Ampholine gel is set up in the tank and thick filter paper strips are soaked with either the anodic or cathodic electrolyte and placed along the appropriate edge of the gel. The samples may be applied either to small filter paper squares laid on the surface of the gel or, for bulk preparative work, incorporated in the gel. The appropriate voltage is applied through terminals attached to the electrode wicks and after about 30 min can be switched off to permit the removal of the sample filter papers before continuing the separation. 

Zonal techniques may be used for the separation of a wide range of particles and macromolecules, e.g. mitochondria, nuclei, ribosomes and proteins. The technique may be used for bulk preparative work using a zonal rotor which is filled with a solvent gradient while running at a slow speed. The sample is similarly introduced and the rotor speed is then increased to the desired value. After centrifugation is complete, the contents are drawn off while the rotor is running slowly by displacing them with a more dense solution. 

Preparative rotors are used for small bulk preparation of tract ons of a sample. 

Hie first efficacy studies were performed with guinea pig l-ASP, but bulk preparation of the enzyme turned out not to be feasible. Large-scale production... 

Incubate all the tubes on ice for 20 min. NOTE It is very important that the protein solution be brought up to the desired ammonium sulfate saturation slowly. If this step is not done correctly, it will be difficult to reproduce these results when the same procedure is carried out on the bulk preparation. Also, avoid frothing in the solution (a sign that some of the proteins are being denatured) by gently mixing the solution as the ammonium sulfate is added. 

Tetrazene can be obtained from the reaction of tetrazenium salts N4H7+X with bases. The tetrazenium salts are formed in small amounts in the decomposition of diazene, which is catalyzed by acids. For the bulk preparation of trans-2-tetrazene, the trimethylsilylderivative of tetrazene is reacted with trifluoroacetic acid at 195 K. ... 

Of these methods, alkali isomerization of soaps is the least expensive process for bulk preparation of CLA isomers however, the use of either monohydric or poly-hydric alcohols in alkah isomerization of CLA can be problematic. Lower alcohols are readily removed from the CLA product, but they require that the production facihty be constructed to support the use of flammable solvents. Higher molecular weight alcohols and polyhydric alcohols are considerably more difficult to remove from the product and residual levels of these alcohols (e.g., ethylene glycol) may not be acceptable in the CLA product. 

Pasteurization is the heating of aqueous, stabilized protein solutions. Pasteurization has been used for bulk preparations of Factor VIII, antithrombin III, and alphai-antitrypsin but wet heat treatment of these... 

Water for injections in Water for the bulk preparation of medicines... 

Bulk electrolyses are used to prepare one-electron reduction or oxidation products. If cyclic voltammetry (CV) reveals reversible redox, the bulk preparation of the reduced (or oxidized) product may be attained. The overall electrode process may be different in controlled-potential electrolysis and in CV because of the time factor (see below). The iron cluster, (h -CjHjFeCO), in nonaqueous electrolytes undergoes a four-membered electron-transfer CV series through three steps. The potentials measured (in CHjCN/O.l M [n-Bu N] [PFJ) are ... 

Electrochemical Reactions 12.3.5. Electrochemical Synthesis 12.3.5.2. Involving Bulk Preparations. 

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