Wrong gas/liquid partition data by gas chromatography.

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Chromatography

Background:

• Previous work reported retention indices and standard chemical potential differences (SPOT-s) for ~160 solutes on a C78 branched paraffin stationary phase.
• The temperature dependence of SPOT-s was modeled using Kirchhoff's proposal, assuming constant molar heat capacity differences at higher temperatures.
• Data were collected under conditions minimizing adsorption effects.

Purpose of the Study:

• To identify and correct erroneous thermodynamic data for solutes determined on a C78 branched paraffin stationary phase.
• To provide corrected data for accurate analysis of solute-gas-liquid interactions in gas chromatography.
• To address inaccuracies in subsequent studies that relied on the original C78 data.

Main Methods:

• Comparison of retention data from a C78 stationary phase with data from a C87 branched paraffin stationary phase.
• Identification of discrepancies in experimentally determined thermodynamic constants (group "H") at higher temperatures.
• Development and application of a correction method for the erroneous data.

Main Results:

• Significant errors were found in the reported thermodynamic constants for solutes on the C78 stationary phase when compared to the C87 phase.
• A method for correcting these erroneous data was developed and applied.
• Corrected thermodynamic data for solutes on the C78 phase are presented.

Conclusions:

• The original thermodynamic data for solutes on the C78 stationary phase were inaccurate, impacting subsequent studies.
• The developed correction method provides reliable thermodynamic constants for solutes on the C78 phase.
• The corrected data are essential for accurate interpretation of solute interactions and for research utilizing polar derivatives of C78.