TAPS ( ris(hydroxymethyl)methylaminoropanesulfonic acid) is a chemical compound commonly used to make

buffer solution A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is ...

s. It can bind

divalent In chemistry, the valence (US spelling) or valency (British spelling) of an chemical element, element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, ...

cations An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by con ...

, including Co(II) and Ni(II). TAPS is effective to make buffer solutions in the pH range 7.7–9.1, since it has a p''K''_a value of 8.44 ( ionic strength I = 0, 25 °C). The pH (and p''K''_a at I ≠ 0) of the buffer solution changes with concentration and temperature, and this effect may be predicted e.g. using online calculators.

References

{{reflist Buffer solutions Sulfonic acids Triols