High-speed isocratic and gradient liquid-chromatography separations at 1500bar

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Ultra-high-pressure liquid chromatography (UHPLC) instrumentation enables higher column pressures (up to 1500 bar) to improve sample throughput and separation efficiency.
• Core-shell particles offer enhanced performance in LC separations.

Purpose of the Study:

• To assess the performance limits of isocratic and gradient UHPLC using core-shell particle columns.
• To investigate the impact of increased operating pressure and reduced particle size on analysis time and separation efficiency.

Main Methods:

• Minimized extra-column band broadening contributions in an optimized UHPLC system configuration.
• Evaluated UHPLC performance using columns packed with 1.5μm core-shell particles at pressures up to 1500 bar.
• Assessed isocratic and gradient elution modes, analyzing kinetic time-gain factors.

Main Results:

• Achieved minimum reduced plate heights of 1.8 with optimized system and 1.5μm core-shell columns.
• Reduced analysis time by a factor of 1.5 in isocratic mode by increasing pressure and decreasing particle size, maintaining separation efficiency (N=54,000).
• In gradient mode, a time gain factor of nearly 13 was achieved by increasing operating pressure to 1500 bar, without compromising peak capacity for wastewater pollutant separation.

Conclusions:

• UHPLC with core-shell particles and high operating pressures significantly enhances analytical throughput.
• Optimizing system configuration and operating parameters (pressure, gradient steepness) is crucial for maximizing time gains in UHPLC.
• The study demonstrates the feasibility of rapid and efficient separations for complex mixtures like wastewater pollutants using advanced UHPLC.