Elemental imaging and resolution in energy-filtered conventional electron microscopy.

Area of Science:

• Materials Science
• Biophysics
• Analytical Chemistry

Background:

• Catalase crystals are vital for understanding enzyme function.
• Uranyl acetate staining is a common method for biological sample preparation.
• Elemental distribution mapping requires high spatial resolution microscopy.

Purpose of the Study:

• To image uranium and carbon distributions in catalase crystals using EFEM.
• To determine the spatial resolution achievable for elemental mapping.
• To address artifacts affecting compositional analysis in EFEM.

Main Methods:

• Energy-filtered transmission electron microscopy (EFEM) was employed.
• Imaging utilized carbon K-edge and uranium O4,5-edge signals.
• Analysis considered scattering delocalization and microscope aberrations.

Main Results:

• Achieved 3.4 nm spatial resolution for both carbon and uranium.
• Calculated resolutions considering aberrations were 2.0 nm for C and 1.2 nm for U.
• Artifacts from scattering were identified and corrected.

Conclusions:

• EFEM provides high-resolution elemental mapping of biological samples.
• The study demonstrates effective methods for artifact removal in EFEM.
• Compositional information was successfully obtained from stained catalase crystals.