Dilution relative volatilities through

Infinite Dilution Relative Volatilities through GLC. If the solvent amount injected in the column is high enough so that infinite dilution conditions for the injected solute prevail, it is readily shown (38) that the separation factor becomes equal to the infinite dilution relative volatility ... 

Doring (39) has shown that infinite dilution relative volatilities can be evaluated through GLC. He prepared a special column for each solvent under consideration, a tedious project. A year later Sheets and Marchello (38) showed that separation factors increase with increased amounts of injected solvent. Later Tassios (35) found out the same to... 

Solvent-based materials are relatively inexpensive and their viscosity can be easily controlled through dilution with volatile solvents. 

Various precolumn concentration procedures used in conjunction with thermal focusing are desirable for biochemical applications. Novotny and Farlow [65] developed a simple technique, where an off-line injection of a relatively large dilute sample onto a small precolumn results in effective concentration. In this procedure, a small volume of deactivated solid support is packed into the glass liner of an injection system. After the volatile solvent is removed, the liner is quickly introduced into the injection port, and the desorbed sample is trapped for several minutes in the cool column. Chromatograms obtained through the following temperature program-... 

Other ways of indirect sampling onto a capillary column involve the injections of (relatively nonvolatile) samples diluted in a sufficiently large (measurable) volume of a volatile solvent (which serves as a sample vehicle ). With the column inlet kept at a sufficiently low temperature, the nonvolatile sample trace is trapped at the inlet and focused into a narrow zone, while the volatile solvent is allowed to pass through the column and widely separate from the sample. A subsequent increase of temperature permits the sample zone to desorb from its inlet position and enter the usual separation process. 

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