Modular, cost-effective, and portable capillary gradient liquid chromatography system for on-site analysis

Area of Science:

• Analytical Chemistry
• Chromatography
• Separation Science

Background:

• Traditional liquid chromatography systems can be bulky and expensive.
• There is a need for compact, cost-effective, and precise separation systems for specific analytical challenges.
• Gradient capillary liquid chromatography offers advantages in solvent consumption and sensitivity.

Purpose of the Study:

• To develop a compact, modular, and cost-effective separation system.
• To achieve high precision and repeatability in gradient capillary liquid chromatography.
• To demonstrate the system's performance for separating complex mixtures.

Main Methods:

• Development of a system using precision stepper motor-driven syringe pumps.
• Integration of a variable loop volume injection valve and a custom-built UV absorbance detector with LED.
• Utilized linear gradient elution on a C18 capillary column for performance evaluation.

Main Results:

• Achieved excellent flow-rate precision (<1% RSD) from 1 µL/min to 100 µL/min.
• Demonstrated high day-to-day repeatability (<1.5% RSD for peak area, <0.4% RSD for retention time).
• Successfully separated a 5-component mixture using a 50 mm capillary column.

Conclusions:

• The developed portable capillary liquid chromatography system is compact, modular, and cost-effective.
• The system provides high precision and repeatability, suitable for demanding separation tasks.
• It offers flexibility to use various commercial or in-house packed capillary columns.