Buffers
Buffer / pH
Henderson-Hasselbalch, the acid/base split for a target pH.
pH = pKa + log₁₀([A⁻]/[HA])
Protocol result
⚗ Aliquot
Buffer / pH · pH = pKa + log₁₀([A⁻]/[HA]) · the lab bench, calculated
Buffer (Henderson-Hasselbalch)✓ pH = pKa + log₁₀([A⁻]/[HA])
For pH 8, combine 23.28 mM conjugate base with 26.72 mM acid.
1
Prepare a 50 mM total buffer solution.
2
Use a base : acid ratio of 0.871 : 1 (46.55% base, 53.45% acid).
3
Verify and fine-tune the final pH on a calibrated meter.
ℹ
Henderson-Hasselbalch uses concentrations, not activities, it ignores ionic strength and activity effects. Real buffers can deviate by ~0.1-0.3 pH units; the pH meter is ground truth.
Target pH
8
[A⁻] base
23.28 mM
[HA] acid
26.72 mM
Ratio A⁻:HA
0.871