Dissolve 50 g of potassium cyanide in sufficient water to make 100 mL. Remove the lead from this solution by extraction with successive portions of Dithizone Extraction Solution, as described under Ammonium Citrate Solution above, then extract any dithizone remaining in the cyanide solution by shaking with chloroform. Finally dilute the cyanide solution with sufficient water
so that each 100 mL contains 10 g of potassium cyanide.