Sample preparation for MALDI mass spectrometry using an elastomeric device reversibly sealed on the MALDI target

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Traditional matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) sample preparation involves multiple steps like desalting and concentration.
• Conventional methods often lead to sample loss, especially for low-concentration analytes.
• These steps typically require transferring samples, increasing the risk of contamination and errors.

Purpose of the Study:

• To develop an improved sample preparation method for MALDI MS that enhances recovery and reduces preparation steps.
• To introduce a novel approach using an elastomeric device integrated with the MALDI target.
• To streamline the entire sample handling process, from deposition to analysis.

Main Methods:

• An elastomeric device was reversibly sealed onto a MALDI target, creating a multi-well plate format.
• Larger sample volumes (5-200 microL) were deposited directly onto the MALDI target within the wells.
• Integrated sample handling processes, including novel hydrophobic surface-based desalting and in-well trypsin digestion, were performed.

Main Results:

• Multiple sample transfer steps were successfully eliminated, simplifying the workflow.
• Improved recovery of low-concentration peptides was achieved through a novel desalting method utilizing the elastomeric device's hydrophobic surface.
• Enhanced peptide mass fingerprinting sequence coverage resulted from in-well protein immobilization, digestion, and concentration.

Conclusions:

• The developed elastomeric device-based method significantly improves sample preparation efficiency for MALDI MS.
• This approach offers enhanced recovery of low-concentration peptides and improved sequence coverage in peptide mass fingerprinting.
• The integrated workflow reduces sample handling, minimizes loss, and streamlines the overall analytical process.