Development of a HPLC system using a phase-separation multiphase flow as an eluent coupled to a silica-particle...

Area of Science:

• Analytical Chemistry
• Chromatography
• Separation Science

Background:

• Traditional high-performance liquid chromatography (HPLC) methods face challenges in separating complex mixtures efficiently.
• Developing innovative eluent systems and separation modes is crucial for advancing chromatographic performance.
• Understanding multiphase flow dynamics within chromatographic columns is key to optimizing separation.

Purpose of the Study:

• To develop and characterize a novel HPLC system employing a phase-separation multiphase flow eluent.
• To investigate the separation capabilities of this system using mixed eluents and model analytes (2,6-Naphthalenedisulfonic acid and 1-naphthol).
• To explore the influence of temperature on separation efficiency in both normal-phase and phase-separation modes.

Main Methods:

• Development of a phase-separation HPLC system combining multiphase flow eluents with a silica-particle packed column.
• Application of various water/acetonitrile/ethyl acetate and water/acetonitrile mixed eluents at 20°C and 0°C.
• Analysis of model analytes 2,6-Naphthalenedisulfonic acid (NDS) and 1-naphthol (NA) using the developed system.
• Computer simulation of multiphase flow within sub-μm inner diameter cylindrical tubes.

Main Results:

• The developed HPLC system demonstrated effective separation of NDS and NA in organic solvent-rich eluents at 20°C (normal-phase mode).
• At 0°C, the system exhibited phase-separation multiphase flow, leading to more efficient separation, with NA detected earlier than NDS in organic-rich eluents.
• In water-rich eluents, separation was achieved at 0°C (phase-separation mode) but not at 20°C, with NDS detected earlier than NA.

Conclusions:

• The phase-separation mode in HPLC, utilizing multiphase flow eluents at low temperatures, significantly enhances separation efficiency compared to conventional normal-phase mode.
• The system's ability to separate analytes differently based on eluent composition and temperature provides a versatile tool for complex mixture analysis.
• The study provides insights into the separation mechanism of phase-separation mode and multiphase flow dynamics, paving the way for optimized chromatographic designs.