This titration method lets you determine what your lead (Pb) assay contain is:
- Volume of the solution before boiling is 65 cc.
- Water and 10 cc H2SO4. Boil gently 5 minutes.
- Filter hot at approximately 93°C or cold at 23ºC.
- Ethyl alcohol added when required.
- No.2 munktell filter papers.
- Wash three times with cold water, 8 to 10 cc. Each.
For samples containing less than 20 mg in lead use 1 cc of ammonium acetate per 10 mg. Lead.
Add torn filter paper to original beaker and approximately 150 cc hot water. Boil 10 minutes before titrating. Use drops of tannic acid as indicator.
When the first indication of an end point is obtained, place the beaker on the hot plate and test at intervals until a permanent end point is reached.
Sulphate loss filtered at 93ºC. Without alcohol is 2.9 mg.