The background of the transmission electron microscope (TEM) detection has many black granular substances that look like they have wrapped around the particles. What could be the reason?

There can be multiple reasons for the appearance of large black agglomerates in transmission electron microscopy (TEM) detection. Here are some common reasons for your reference:

1. Sample Preparation Issues

• Staining Residue: During the sample staining process, the staining agent may not have been completely washed away, resulting in residues that form black agglomerates in the background.
• Incomplete Sample Drying: If the sample is not completely dried during the drying process, it may lead to solvent residues forming black clumps.
• Fixative Issues: During sample fixation, the fixative may not be evenly distributed or sufficiently penetrated, leading to fixative residues.

2. Sample Contamination

• External Contamination: The sample may be contaminated by external substances such as dust and fibers during preparation or transfer.
• Instrument Contamination: The sample stage or other components of the transmission electron microscope may be contaminated, affecting image quality.

3. Intrinsic Sample Properties

• Aggregation Phenomenon: The sample itself may exhibit spontaneous aggregation, forming clumps.
• Degradation Products: The sample may undergo degradation during preparation, forming insoluble products.

4. Imaging Parameter Issues

• Electron Beam Damage: An overly strong electron beam may damage or carbonize the sample, forming black agglomerates.
• Imaging Conditions: Improper settings of parameters such as voltage and current during imaging may degrade image quality, resulting in artifacts.

 

Suggested Solutions:

1. Optimize Sample Preparation Process

• Ensure sufficient application and rinsing of staining and fixative agents.
• Ensure complete drying of the sample to avoid solvent residues.

2. Avoid Contamination

• Prepare and transfer samples in a dust-free environment.
• Regularly clean the sample stage and other components of the transmission electron microscope to avoid instrument contamination.

3. Adjust Imaging Parameters

• Appropriately adjust the strength of the electron beam to avoid sample damage.
• Optimize voltage and current parameters based on the characteristics of the sample.

 

Please note that specific handling methods should be determined based on the nature and experimental purpose of your sample. Multiple attempts and optimizations may be required to solve the problem.

 

BiotechPack, A Biopharmaceutical Characterization and Multi-Omics Mass Spectrometry (MS) Services Provider

 

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