This method is for determining total fluoride in aluminosilicate catalysts and molecular sieves, and inorganic fluoride in aqueous samples. The method is particularly useful for catalysts containing zirconia or other metals that interfere with alternative procedures. The range of fluoride typically determined is from 0.01 to approximately 20 mass-% for catalysts or molecular sieves, and 0.01 to approximately 50 mass-% for aqueous samples.