Reference

Buffer pKa values and temperature coefficients

pKa at 25 C for the buffers used on a biochemistry bench, with the temperature coefficient that tells you how far the pH moves when you take the buffer to the cold room. A buffer only buffers within about one pH unit of its pKa.

Open the Buffer / pH calculator

Buffer	pKa (25 C)	dpKa/dT (per C)	Useful pH range	Acid MW	Base MW
Acetate	4.76	+0.0002	3.8 to 5.8	60.05	82.03
MES	6.10	-0.0110	5.1 to 7.1	195.24	217.22
PIPES	6.76	-0.0085	5.8 to 7.8
Phosphate (pKa2)	7.20	-0.0028	6.2 to 8.2	119.98	141.96
MOPS	7.20	-0.0110	6.2 to 8.2
HEPES	7.48	-0.0140	6.5 to 8.5	238.30	260.28
Tricine	8.05	-0.0210	7.1 to 9.1
Tris	8.06	-0.0280	7.1 to 9.1	157.60	121.14
Bicine	8.26	-0.0180	7.3 to 9.3
TAPS	8.40	-0.0180	7.4 to 9.4
CHES	9.30	-0.0290	8.3 to 10.3

Notes

The useful range is pKa plus or minus 1. Outside it there is very little buffering capacity left, however good the arithmetic looks.
Tris moves about -0.028 pH units per degree C, so a Tris buffer titrated at 22 C is a noticeably different pH at 4 C. Titrate at the temperature you will use it.
A blank molar mass means this data set does not carry one for that form, not that the buffer has none.

Source

CRC Handbook; Beynon & Easterby 1996 | Good et al., Biochemistry 1966, 5(2):467-477; Beynon & Easterby 1996 | CRC Handbook (pKa2 7.20)

These values are imported from the same data the Aliquot calculators use, so this page cannot drift away from what the tools compute.

Calculators that use this data

Buffer / pH: Henderson-Hasselbalch, the acid/base split for a target pH.
Buffer pH temperature corrector: Dial in the bench pH so your buffer hits target at working temperature.
Buffer builder: Build a multi-component buffer from stocks and solids.
Buffer harmonizer (reverse solver): Target pH and stocks in, an exact volume-closed recipe out.

Buffer pKa values and temperature coefficients

Notes

Source

Calculators that use this data

Other reference tables