Constant Distance Mode Mass Spectrometry Imaging with a Confocal Sensor

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Mass spectrometry imaging (MSI) in constant distance mode is vital for high-resolution analysis of complex samples.
• Variations in sample height during MSI experiments lead to signal instability, regardless of ionization method.
• Existing methods may struggle with diverse sample topographies and optical properties.

Purpose of the Study:

• To develop and validate a noncontact, real-time sample height control system for MSI.
• To enhance signal stability and data quality in MSI experiments, particularly those with challenging sample surfaces.
• To provide a versatile solution applicable to various MSI techniques.

Main Methods:

• Integration of a confocal distance sensor for noncontact sample height measurement.
• Real-time feedback control system to maintain constant sample-to-emitter distance during MSI.
• Demonstration using constant distance mode nanospray desorption electrospray ionization (nano-DESI) MSI.

Main Results:

• The confocal sensor provides submicrometer distance resolution.
• Achieved stable MSI data acquisition by effectively compensating for sample height variations.
• Demonstrated compatibility with diverse surface optical properties.

Conclusions:

• A confocal distance sensor offers a robust solution for real-time sample height control in MSI.
• This technology significantly improves signal stability for MSI of samples with complex topography.
• The sensor is a versatile tool applicable to various MSI techniques, enhancing their performance.