Two-pump at-column-dilution configuration for preparative liquid chromatography-mass spectrometry

Area of Science:

• Analytical Chemistry
• Chromatography
• Mass Spectrometry

Background:

• Preparative liquid chromatography-mass spectrometry (LC-MS) is crucial for purifying compounds in parallel synthesis.
• Existing methods often require separate pumps for sample loading and gradient elution.
• At-column dilution has shown potential to increase mass loading capacity in LC-MS.

Purpose of the Study:

• To develop and demonstrate a simplified two-pump system for at-column dilution in LC-MS.
• To reduce the cost, space, and complexity of LC-MS purification systems.
• To validate the effectiveness of the two-pump at-column dilution configuration for various scales of purification.

Main Methods:

• A novel configuration utilizing only the two binary gradient pumps for at-column dilution was implemented.
• The system was tested for both large- and small-scale LC-MS purifications.
• Demonstrated purification of 20 mg of material using a 4.6 mm x 150 mm column at a flow rate of 3 mL/min.

Main Results:

• The two-pump at-column dilution configuration successfully increased mass loading capacity for LC-MS.
• Simplified system design led to reduced cost, space requirements, and operational complexity.
• Effective purification was achieved at scales suitable for high-throughput parallel synthesis, including 20 mg scale using standard chromatography columns.

Conclusions:

• The two-pump at-column dilution method offers a cost-effective and efficient approach to LC-MS purification.
• This configuration significantly benefits high-throughput parallel synthesis by enabling smaller-scale chromatography.
• Reduced solvent consumption, faster fraction dry-down times, and compatibility with microplate formats are key advantages.