Tetrahydrofuran, solvent, RPLC

The isocratic reversed phase solvent system consists of water (polarity, p = 10.2), the most polar solvent in RPLC, as a primary solvent to which water-miscible organic solvents such as methanol (p = 5.1), acetonitrile (p = 5.8), or tetrahydrofuran (p = 4.0) are added. In order to optimize the speed of separation for an analyte pair, the proportions of water to nonpolar solvent are chosen such that the capacity factor of the last-eluting analyte of interest has a value of about 2.13... 

The most commonly used solvents for RPLC are methanol, acetonitrile, and tetrahydrofuran, used in binary, ternary, or quaternary combinations with water. The effect of solvent strengths can be seen in... 

For RPLC, the three solvents chosen were methanol from group 2, acetonitrile (ACN) from group 6, and tetrahydrofuran (THF) from group 3. These three solvents are not as widely separated from each other in the diagram as those for normal phase are, but they are sufficiently different to produce good separations. The (polar) carrier solvent used was water, and the stationary phase was a C8 bonded phase. The procedure... 

Improvements in stationary phase design have advanced to a more coherent technology for achieving, at least in practical terms, well defined sorptive effects. Equally important, similar progress has been made toward improved practical understanding of liquid phase compositions needed to achieve chemical selectivity. Preliminary solvent selection has been reduced to the use of solvent triads, one for aqueous and another for non-aqueous systems (14). Thus, aqueous mixtures for reversed phase HPLC, or RPLC, are prepared with methanol, acetonitrile, and/or tetrahydrofuran as... 

Several surfactants of different types (nonionic, anionic, cationic, and zwitterionic) have been assayed, but most reported procedures use the anionic surfactant sodium dodecyl sulfate (SDS, CMC = 8.2xl0 moll-i at 25°C), which is readily available. Other common surfactants are the cationic cetyltrimethylammonium bromide (CTAB, CMC = 9 X 10 moll ), and the nonionic Brij-35 (polyoxyethylene (23) dodecyl ether, CMC = 1 X 10 moll ). Common solvents in RPLC (methanol, ethanol, propanol, acetonitrile, and tetrahydrofuran) are suitable modifiers. Other less polar solvents, such as butanol and pentanol, can... 

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