Eriochrome Black T - Complexometric indicator.
Black or brown crystals, readily soluble in alcohol, poorly soluble in water. Toxic.
Eriochrome black T - an indicator that is widely used in analytical chemistry for the determination of metals (by direct or reverse complexometric titration). Typically, titration is carried out in black eryochrom medium ammonia buffer (pH about 9.5). In particular, since the total water hardness determined (the content of cations of calcium, magnesium and iron).
Is used as an indicator for complexometric determining ions Mg, Mn, Pb, Zn, Cd, In, Zr, lanthanides. In the pH range 9,5-10,0 has a blue color, and its complexes with ions of calcium, magnesium and zinc in the same conditions as a red-violet color.