RNALater Recipe

Overview: This buffer mimics the RNAlater that you can buy from Ambion. Both DNA and RNA are stable at room temperature in this buffer.

This recipe was first published by in the Molecular Ecology Resources paper “Preservation of RNA and DNA from mammal samples under field conditions” (Camacho-Sanchez, M., P. Burraco, I. Gomez-Mestre, and J. A. Leonard. 2013).

Materials:

  • EDTA disodium, dehydrate (Thermo Fisher Cat# 2793-500 or BP120-1)
  • Sodium citrate trisodium salt, dihydrate (Fisher Cat# S279-500)
  • Ammonium Sulfate (Thermo Fisher Arcos Org #423400050)
  • Ultrapure water, ok to use Millipore water that has been autoclaved or Ambion nuclease-free water
  • Sulfuric acid, H2SO4 to adjust the pH, if necessary (Fisher Cat# A300-500)

Lab Equipment Needed:

  • sterile flask
  • stir bar and stir plate with hot plate
  • scale
  • graduated cylinder: bleach bath/rinse w/Millipore H2O
  • pipette
  • pH reader
  • autoclave

To make RNALater

  1. Combine the following:
    • 40mL 0.5M EDTA
    • 25mL 1M Sodium citrate
    • 700g Ammonium sulfate
    • 935mL Ultrapure water
  2. Stir on low to moderate heat until the Ammonium sulfate dissolves completely.
  3. Allow to cool and then adjust the pH to 5.2 with H2SO4, if necessary.

Store at room temperature or keep refrigerated until used.

To make 40mL of 0.5M EDTA

Add 7.44g EDTA to 40mL Ultrapure water

The math:

(0.04L= 40mL) (0.5M)= 0.02 moles of EDTA

(0.02 mol) (formula weight of EDTA= 372.24g/mol)= 7.44g

Adjust pH to 8

To make 25mL of 1M Sodium Citrate

Add 5.88g Sodium citrate to 25mL Ultrapure water

The math:

(0.025L) (1M)= 0.02 moles of sodium citrate

(0.02 mol) (formula weight of sodium citrate= 294.10g/mol)= 5.88g