A parallel method for desalting and concentrating microliter volume samples for mass spectrometry

Area of Science:

• Analytical Chemistry
• Biochemistry
• Proteomics

Background:

• Proteolytic digests often require desalting prior to mass spectrometry analysis.
• Existing desalting methods can be time-consuming and not amenable to parallel processing.
• Efficient sample preparation is crucial for high-quality mass spectrometry data.

Purpose of the Study:

• To develop a novel, rapid, and efficient method for reverse-phase centrifugal desalting of proteolytic digests.
• To create self-packed, reusable spin columns for parallel sample processing.
• To evaluate the efficiency of peptide recovery and its impact on mass spectrometry analysis.

Main Methods:

• Construction of small, self-packed, reusable spin columns.
• Reverse-phase centrifugal desalting of proteolytic digests.
• Optimization of column packing, sample loading, and elution using various C18 resins and solvents compatible with electrospray ionization.

Main Results:

• The method processed six samples in under 30 minutes, demonstrating parallel processing capability.
• Peptide recovery ranged from 60% to 90% for loads between 0.5 to 250 pmol, depending on resin and load.
• Desalting significantly improved matrix-assisted laser desorption and ionization/time-of-flight mass spectrometry data quality, even for samples with urea contamination.

Conclusions:

• Self-packed spin columns offer an efficient and rapid solution for desalting proteolytic digests.
• The technique is versatile, suitable for various silica resins and compatible with nanospray analysis.
• This method enhances sample throughput and data quality in proteomics workflows.