On-probe solid-phase extraction/MALDI-MS using ion-pairing interactions for the cleanup of peptides and proteins

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Biological samples contain complex mixtures of contaminants.
• These contaminants interfere with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis.
• Effective sample cleanup is crucial for successful MALDI-MS.

Purpose of the Study:

• To develop a simplified sample preparation method for MALDI-MS.
• To address challenges in analyzing biological samples with high contaminant levels.
• To improve the success rate of peptide and protein analysis using MALDI-MS.

Main Methods:

• A probe-surface derivatization method was developed.
• Self-assembled monolayers (SAMs) terminated with ionic functional groups were used on MALDI probes.
• Ionic interactions were employed to extract peptides/proteins from small sample volumes (< or = 1-microL).

Main Results:

• The method effectively simplifies sample preparation for MALDI-MS.
• MALDI probes with SAMs rapidly extract peptides/proteins from contaminated solutions.
• Successful analysis was achieved for samples with high levels of salts, buffers, detergents, and chaotropic agents.

Conclusions:

• The probe-surface derivatization method is a practical solution for MALDI-MS sample preparation.
• This technique enables the analysis of very small volumes of contaminated biological samples.
• The method enhances the reliability and success of peptide and protein identification via MALDI-MS.