Visualization and identification of single meteoritic organic molecules by atomic force microscopy

Area of Science:

• Astrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Meteorites contain complex organic molecules relevant to astrobiology.
• Characterizing these extraterrestrial organic compounds at the molecular level is challenging.
• Previous methods lacked the resolution to identify individual molecules directly within meteorite samples.

Purpose of the Study:

• To demonstrate the capability of high-resolution atomic force microscopy (AFM) for identifying individual organic molecules in meteorite samples.
• To develop and validate a sample preparation method for AFM analysis of meteorite organic constituents.
• To investigate the types of organic molecules present in the Murchison meteorite using AFM.

Main Methods:

• Utilized high-resolution atomic force microscopy (AFM) with CO-functionalized tips for molecular imaging.
• Developed a multi-step trituration and organic solvent extraction procedure to isolate larger organic compounds from meteorite powder.
• Complemented AFM analysis with high-resolution mass spectrometry for detailed chemical characterization.

Main Results:

• Atomic force microscopy successfully resolved and identified individual organic molecules from processed Murchison meteorite samples.
• The developed extraction method significantly enriched the sample in larger organic compounds, improving AFM resolvability.
• Identified specific molecular moieties, including polycyclic aromatic hydrocarbons and aliphatic chains, within the meteorite extract.
• AFM imaging provided direct visualization of extraterrestrial organic molecular structures.

Conclusions:

• Atomic force microscopy (AFM) offers a powerful new approach for the direct imaging and identification of individual organic molecules in extraterrestrial samples.
• The presented sample preparation technique enhances the yield and quality of AFM analysis for meteorite organic matter.
• This methodology paves the way for detailed single-molecule studies of organic compounds in meteorites and other extraterrestrial materials.