The UC Center for Laboratory Safety

What Happened?

During an RNA extraction a solution of Phenol:Chloroform: Isoamyl Alcohol (25:24:1) was added to multiple small Eppendorf tubes along with the samples, mixed and placed in a centrifuge. For phase separation.

Several microfuge tubes had cracked during the centrifugation. While removing the tubes from the centrifuge, the researcher felt a numbing feeling on their gloved hand. The researcher noticed that residues from the outside of the tubes had penetrated the nitrile glove.

What Was The Cause?

The investigation discovered that multiple tubes (about 6) had been cracked during centrifugation. The centrifuge had debris in it, which was the likely cause of the cracked tubes. The debris was likely present before the researcher placed their samples in the centrifuge.

Additionally, the researcher was performing the operation with nitrile gloves, which are not recommended when handling chloroform due to degradation caused by the solvent. Glove degradation allowed the solution, including the phenol, to permeate to the researcher’s gloved hands.  

How Can Incidents Like This Be Prevented?

• When working with mixtures, consider the highest level of PPE that is needed for all chemicals involved. Double gloving Neoprene gloves are recommended when working with chloroform.
• Ensure that no debris is present in a centrifuge before use. Clean any spills in centrifuges immediately after use.

Recommendations

• When using any hazardous chemicals including mixtures ensure to use the correct type of glove.
• Discuss types of gloves and usage in your lab meeting.
• Post commonly used hazardous chemicals and appropriate glove types in your lab.
• Discuss in your lab meeting the importance of keeping equipment clean and in good working order so not to endanger other lab members. 

Resources

• SDS Chloramphenicol
• SDS Phenol 
• Honeywell chemical resistance guide for nitrile gloves 
• Halogenated Solvents SOP