Chasing the elusive hold-up time from an LFER approach

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Accurate determination of hold-up times is crucial for chromatographic method development.
• Existing models may not fully capture the complexities of various chromatographic systems.

Purpose of the Study:

• To develop and validate a homologous series approach for determining hold-up times.
• To apply this method to both reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC).

Main Methods:

• Utilized Abraham's solvation model to derive a homologous series approach.
• Tested the approach with literature data from RPLC.
• Applied the method to a zwitterionic HILIC column using n-alkyl benzenes and n-alkyl phenones.
• Investigated the effect of acetonitrile and methanol as organic modifiers (80-100% v/v).

Main Results:

• The homologous series approach yielded consistent results for both RPLC and HILIC.
• Hold-up times demonstrated strong dependence on mobile phase water content.
• The nature of the organic modifier significantly influenced hold-up times.

Conclusions:

• The developed homologous series approach is a reliable tool for predicting hold-up times.
• This method offers valuable insights into mobile phase effects in chromatography.
• The findings are applicable to optimizing chromatographic separations.