Separation general strategies

A general strategy for assigning responsibilities is to begin with the holder of the responsibility as a separate role, such as VacationScheduler (see Figure 1.29). Then you decide whether and how to combine the roles (see Figure 1.30). 

The strategy employed for choosing a particular chromatographic separation generally entails maximizing the column efficiency and, at... 

For RPLC, the general strategy (Figure 3.10a) is less complex because no distinction between acidic and basic compounds is made. The optimization stage is also less complicated. In case of a baseline separation, the retention factor can be optimized based on the fact that a linear relationship is assumed between log k and the fraction... 

Fig.l. General strategy of the Chemically Induced Phase Separation (CIPS) technique to prepare macroporous thermosets having a closed cell morphology... 

The preparation of fused nitrogen heterocycles such as pyrrolizidines, indolizidines, quinolizidines, pyrrolidinoazocines and piperidinoazocines by the RCM of appropriate dienes (equation 38), is another case where presence of a ring assists the RCM reaction. However, when n = 7 (with x = 1), the C=C bonds, separated by 11 single bonds, are too far apart for RCM to occur. Applications of this general strategy are in prospect for the formation of fused nitrogen heterocyclic systems in problems of alkaloid synthesis240. 

The general strategy of multistep electron transfers in triad-type molecules has proven to be a useful one for maximizing the quantum yield of charge separated states formed by photoinitiated electron transfer, the lifetimes of these states, and the amount of energy stored therein. As a result, the strategy has been exploited in a variety of molecular devices, many of which are reviewed below. 

The first rule of thumb to remember is that there is no single approach to developing a satisfactory separation. Most problems can ultimately be solved by more than one mode of LC. Therefore, a general strategy for the analyst to follow is presented. 

In the following case study for this pharmaceutical compound M, the method development scenario and rationale for each iteration in the method development process is highlighted. Also, a method development flow chart for gradient separations is included which can be used as a general strategy for method development (Figure 8-37). References are made in this case study to the flow chart in Figure 8-37. 

Fig. 15.5. Schematic depiction of the generalized strategy for preparation of polymeric nanostructures via bulk phase-separated block copolymers.

The general strategy for determining the sequence of amino acids in a peptide or protein involves several steps. It is necessary (a) to hydrolyse the molecule completely and to determine quantitatively the relative molar proportions of amino acids present (Chapter 4) (b) to determine the molecular weight in order to calculate the number of residues of each amino acid present (c) to determine how many peptide chains are present and to separate these, bearing in mind that these may be... 

Generally, strategy 1 is applied first and consists in identifying the CSP providing the best selectivity. Numerous preparative applications which follow fhis approach have been reported. Some tools, such as an electronic data base [82, 83] and user guides are available to help in the choice of the appropriate CSP, but the screening of a few CSPs is still fhe more commonly used approach in practice. There are only rare cases for which the chromatographic separation could be predicted. 

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