TE

Purpose

TE buffer is often used to store DNA and RNA.

• EDTA in TE chelates Mg²⁺ and other divalent metals ions necessary for most causes of DNA and RNA degradation, suppressing these processes.
• Tris is a buffering agent to keep the solution at a defined pH.

Recipe 10x TE

for 1 liter of 10x TE stock solution

volume	reagent	final conc.
100 ml	1M Tris-HCl pH 7.5 or 8.0 (see notes)	100 mM
20 ml	0.5M EDTA pH 8.0	10 mM
880 ml	ddH2O

Recipe 1x TE

for 1 liter of 1x TE solution

volume	reagent	final conc.
10 ml	1M Tris-HCl pH 7.5 or 8.0 (see notes)	10 mM
2 ml	0.5M EDTA pH 8.0	1 mM
988 ml	ddH2O

→ 1x TE is 10 mM Tris-HCl and 1 mM EDTA

Notes

• For the Tris-HCl use Tris base and adjust to desired pH using HCl.
• TE buffer is often used to store DNA and RNA. The EDTA in TE chelates Mg²⁺ and other divalent metals ions necessary for most causes of DNA and RNA degradation, suppressing these processes. However, downstream reactions like restriction digests, PCR, ligations, and reverse transcription typically require Mg²⁺, potentially making the presence of EDTA in the reaction problematic. So, when using DNA or RNA that was suspended in TE, you should keep track of the amount of EDTA in the mix to make sure there is still enough Mg²⁺ for subsequent reactions to proceed successfully. Each EDTA molecule chelates one Mg²⁺ ion.
• Some protocols use TE 10:0.1 with 0.1 mM EDTA to reduce the interaction of the EDTA with downstream applications.
• Some people use TE buffers with different pH's for different applications. For example, DNA is stored at pH 8 to reduce depurination, which is acid catalyzed, while RNA is stored at a slightly lower pH (7.5) because degradation of RNA is base-catalyzed. Most downstream reactions will not be influenced by the slightly different pH storage conditions.
• For dilution of primers water for injections can be used rather than TE.

See also

• 10x TE buffer at Cold Spring Harbor Protocols
• 10x and 1x TE at cytographica