Limit tests

For the purity test of which of the following elements is 8-hydroxyquinoline commonly used?

• Magnesium

• Potassium

• Phosphorus

• Cyanide

Which of the following is the main method used to detect potassium impurities in pharmaceutical products?

• Reaction with sodium cyanide

• Precipitation with ammonium phosphate

• Complexation with 8-hydroxyquinoline

• Formation of an insoluble potassium salt

The detection of which elemental impurity depends on the formation of Molybdenum Blue?

• Magnesium

• Potassium

• Phosphates

• Zinc

Which reagent is commonly used to detect ammonium impurities in pharmaceutical products?

• Ammonium molybdate

• Nessler’s reagent

• 8-Hydroxyquinoline

• Potassium tetraphenylborate

Diazotization and coupling reactions are typical for the limit test of which of the following elements?

• Chlorine

• Phosphorus

• Nitrate

• Arsenic