Temperature effects on solute retention for hydride-based stationary phases

Area of Science:

• Analytical Chemistry
• Chromatography
• Physical Chemistry

Background:

• Solute retention behavior in chromatography is typically temperature-dependent.
• Understanding retention mechanisms is crucial for method development and optimization.
• Hydride-based stationary phases offer unique selectivity in chromatographic separations.

Purpose of the Study:

• To investigate the effect of temperature on solute retention for bidentate C18 and cholesterol hydride-based stationary phases.
• To identify conditions and compound types that exhibit unusual temperature-dependent retention behavior.
• To explore the influence of chromatographic mode (reversed-phase vs. aqueous normal phase) on retention temperature effects.

Main Methods:

• Utilized reversed-phase and aqueous normal phase (ANP) chromatography.
• Employed bidentate C18 and cholesterol stationary phases.
• Tested retention of small molecules and peptides across a temperature range.

Main Results:

• Most solutes showed expected decreased retention with increasing temperature in reversed-phase mode.
• Two lisinopril analogs exhibited increased retention with temperature on the cholesterol column.
• An increased number of compounds, including peptides, displayed unusual temperature-dependent retention in ANP mode.
• Stronger ANP retention correlated with a higher likelihood of observing increasing retention with temperature.

Conclusions:

• Hydride-based stationary phases, particularly cholesterol, can lead to inverse temperature retention effects.
• Aqueous normal phase chromatography is more prone to unusual temperature-dependent retention phenomena.
• Further investigation is warranted to elucidate the mechanisms behind this inverse temperature behavior in ANP chromatography.