Soluble-handle techniques

When SPPS was in its infancy, an alternative approach was examined. In this approach the same potential advantages of simple isolation and avoiding the need for full characterisation at each step were sought. The concept involved using a 

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Of the impurity/degradant enhancement techniques available, the phase-solubility analysis technique requires minimal sample handling from the... 

Techniques used in bioseparations depend on the nature of the product (i.e., the unique properties and characteristics which provide a handle for the separation), and on its state (i.e., whether soluble or insoluble, intra- or extracellular, etc.). All early isolation and recovery steps remove whole cells, cellular debris, suspended solids, and colloidal particles, concentrate the product, and, in many cases, achieve some degree of purification, all the while maintaining high yield. For intracellular compounds, the initial harvesting of the cells is important... 

Several manual and continuous analytical techniques are used to measure SO2 in the atmosphere. The manual techniques involve two-stage sample collection and measurement. Samples are collected by bubbling a known volume of gas through a liquid collection medium. Collection efficiency is dependent on the gas-liquid contact time, bubble size, SO2 concentration, and SO2 solubility in the collection medium. The liquid medium contains chemicals which stabilize SO2 in solution by either complexation or oxidation to a more stable form. Field samples must be handled carefully to prevent losses from exposure to high temperatures. Samples are analyzed at a central laboratory by an appropriate method. 

Traditional electrophoresis and capillary electrophoresis are competitive techniques as both can be used for the analysis of similar types of samples. On the other hand, whereas HPLC and GC are complementary techniques since they are generally applicable to different sample types, HPLC and CE are more competitive with each other since they are applicable to many of the same types of samples. Yet, they exhibit different selec-tivities and thus are very suitable for cross-validation studies. CE is well suited for analysis of both polar and nonpolar compounds, i.e. water-soluble and water-insoluble compounds. CE may separate compounds that have been traditionally difficult to handle by HPLC (e.g. polar substances, large molecules, limited size samples). 

Entrapment involves the physical confinement of an enzyme in a semipermeable matrix, in much the same manner as nature handles soluble enzymes. " This should represent an extremely mild method of immobilization, as the enzyme remains free, albeit confined to a small space. Two techniques, which at first sight appear unrelated, have been well utilized ... 

In recent years, several procedures have been developed for handling high molecular weight, water-soluble biomolecules. Several of these procedures are here briefly described. [See the Chapman (1993) and Watson (1985) references for a thorough discussion of these techniques. The Harrison (1992) reference presents a thorough treatment of chemical ionizations.]... 

This technique is necessary either when the solubility of the compound in the requisite solvent is too high at ordinarily obtained temperatures (refrigerator to room temperatures) for recovery to be economic, or when handling compounds which are liquid at room temperature but which may be recrystallised from a solvent maintained at much lower temperatures (say —10 to — 40 °C). In this latter case, after several successive low temperature recrystallisations, the compound will revert to a liquid on storage at room temperature, but the purification process by recrystallisation will have been achieved. 

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