To determine the presence of lead some of the powder was extracted with ammonium acetate solution.
Lead sulphate may be dissolved by boiling with ammonium acetate.
Actually sodium phosphate does not strip, and indeed reduces the stripping power of ammonium acetate.
It is standardized by dissolving a weighed amount of lead sulphate in ammonium acetate and proceeding as described above.
Ammonium sulphide blackens it, and it is coluble in solution of ammonium acetate, which distinguishes it from barium sulphate.
Thus the chrome tannage is reversible in solutions of ammonium or potassium oxalate and of ammonium acetate.
Qualitative tests showed the presence of lead and sulphate in the ammonium acetate solution.