This method is for determining total fluoride in aluminosilicatecatalysts and molecular sieves, and inorganic fluoride in aqueoussamples. The method is particularly useful for catalysts containingzirconia or other metals that interfere with alternativeprocedures. The range of fluoride typically determined is from 0.01to approximately 20 mass-% for catalysts or molecular sieves, and0.01 to approximately 50 mass-% for aqueous samples.