- Tris base CAS
- 77-86-1
- Tris-HCl CAS
- 1185-53-1
- pKa, literature
- 8.07 at 25 °C; about 7.75 at 37 °C
- Note
- pH moves with temperature. Prepare at the working temperature
Tris is the base for TE, TAE, TBE and many protein-gel buffers. It is more temperature sensitive than HEPES. Glycine for Tris-glycine gels is under media supplements, and culture grade is not electrophoresis grade.
What it is
Tris (tris(hydroxymethyl)aminomethane) is a primary-amine buffer with a useful range of about pH 7.0–9.0. It is inexpensive, very soluble and chemically stable, but its pKa falls by about 0.028 per °C, so a buffer set at room temperature reads noticeably more alkaline on ice.
Where it is used
- Nucleic-acid buffers: TE (10 mM Tris, 1 mM EDTA), TAE (40 mM Tris-acetate, 1 mM EDTA) and TBE (89 mM Tris-borate, 2 mM EDTA).
- SDS-PAGE: Laemmli running buffer is 25 mM Tris, 192 mM glycine and 0.1% SDS; resolving gels commonly use 375 mM Tris-HCl at pH 8.8.
- TBS and TBST washes for Western blots, and lysis buffers such as RIPA (often 50 mM Tris-HCl).
- Protein purification and enzyme reactions in the mildly alkaline range.
Handling tips
- Adjust pH at the temperature of use, and use a pH electrode rated for Tris solutions.
- The primary amine reacts with aldehydes and NHS esters, so avoid Tris in amine-coupling steps.
- Mixing Tris base with Tris-HCl in set ratios reaches a target pH without titration.
What to specify when ordering
- Tris base (77-86-1), Tris-HCl (1185-53-1) or Tris acetate.
- Grade: molecular-biology or electrophoresis grade, and any DNase/RNase testing.
- Powder or ready buffer concentrate (for example 10× or 50× TAE / TBE), and pack size.
Properties and storage
- Formula
- C4H11NO3
- Molecular weight
- 121.14 / 157.60
- Appearance
- White crystals or crystalline powder
- Solubility
- Freely soluble in water (about 550 g/L at 25 °C)
- Storage
- Room temperature, dry, sealed
- Typical packs
- 100 g, 500 g, 1 kg, 25 kg
Typical literature values. The batch COA / SDS governs.
Before you inquire
Can Tris replace HEPES in culture?
Only if the pKa at 37 °C still matches the target. For mammalian culture near 7.4, HEPES is the usual inquiry.
Tris base or Tris-HCl?
Tris base is titrated down with HCl. Tris-HCl is titrated up with NaOH or mixed with Tris base. Both give the same buffer; the choice is about convenience and the counter-ion.
Pack sizes and catalogue numbers
Tris
CTH10046-1KG
Prices on request; lead time confirmed on the quotation.
Tris HCl
CTH10047-1KG
Prices on request; lead time confirmed on the quotation.
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Send an inquiryFor research or industrial use only. Not for human or animal diagnosis or treatment, and not for drug or food use. Grade, pack size and lead time follow the supplier batch COA / SDS. Figures on this site are general industry references, not a factory specification.