1.3.2. Freezing with ‘wet’ ice

Short-term field-storage on ‘wet’ (frozen water or ice packs) ice is cheap and very practical for many field-studies and surveys. The samples should be frozen as soon as possible, ideally within hours, and kept frozen continuously until RNA processing (a complete frozen transport chain). If a complete frozen transport chain cannot be guaranteed, then a chemical stabilizing agent (see section 1.3.4.) should be used to prevent degradation of the RNA by RNAses, until the samples enter a frozen transport chain. The most important rule for RNA preservation is to keep the samples as cold as possible, as long as possible and to avoid thawing the sample after it has been frozen unless it is to extract RNA.

  • Samples: all.
  • Conditions: collect in freezer bags, store on wet ice.
  • Transport: cold transport; wet-ice; <12 hours.
  • Processing: transfer samples to freezer.
  • Pros: simple; fast; cheap field operation.
  • Cons: heavy, expensive mail transport, leaks due to thawing.