Hydrocyanic Acid in Beans
A. Acid Titration Method
Place 10-20 g sample, ground to pass No. 20 sieve, in 800 mL Kjeldahl flask, add 100 mL H2O, and macerate at room temperature 2 hour. Add 100mL H2O and steam distil, collecting distillate in 20 mL 0.01Newton AgNO3 acidified with 1 mL HNO3. Before distilling, adjust apparatus so that tip of condenser dips below surface of liquid in receiver. When 150 mL has passed over, filter distillate thru gooch, wash receiver and gooch with little H2O. And titrate excess AgNO3 in combined filter and washing with 0.02 newton KSCN, using Fe alum indicator
1 mL 0.02 newton AgNO3=0.54 mg HCN