Preparation and Use of a Dry Ice / Ethanol Bath
Biotech Glossary |
Bioinformatics |
Lab Protocol |
Notes |
Malaysia University |
Preparation and Use of a Dry Ice / Ethanol Bath
Overview
Dry Ice / Ethanol baths are used to rapidly cool solutions to below freezing temperatures. Dry Ice / Ethanol baths can be used to freeze tissue sections for histology or to rapidly cool Ethanol solutions to induce the precipitation of RNA, DNA, or proteins.
Procedure
1. Find a suitable container to hold the bath (see Hint #1).
2. Break the Dry Ice into easily transferable pieces (see Hint #2).
3. Add several pieces of Dry Ice to the bath.
4. Carefully add the Ethanol Solution to the Dry Ice until it covers the Dry Ice in the bath (see Hint #3).
5. After the Ethanol has cooled down, the solution will "boil" more slowly. As the "boiling" slows, add more Ethanol and / or Dry Ice as necessary.
Solutions
Ethanol Solution
Prepared in ddH2O
70% (v/v) Ethanol*
See Hint #4 
BioReagents and Chemicals
Ethanol
Dry Ice
Protocol Hints
1. The container is usually made of stainless steel or a rubber ice bucket and not plastic. Plastics can crack, causing super cooled Ethanol to leak. Although some high performance plastics can be used as a bath, the plastic will eventually degrade and crack. Find a container with a depth that is appropriate for your application.
2. Be sure to use gloves when handling Dry Ice.
3. Be careful, the Ethanol may splatter and burn you.
4. For general applications, use 70% (v/v) Ethanol, although other concentrations of Ethanol can be used. Remember that as you lower the concentration of Ethanol in the bath, you decrease the overall temperature of the bath solution. If you use 70% Ethanol, tissue sections will freeze evenly but more slowly than if you use 100% Ethanol. When precipitating RNA, DNA, or proteins, the Ethanol Solution can contain 70% to 100% Ethanol.
