This method is for determining the extent of platinum agglomeration in reforming catalysts, i.e., the fraction of the platinum in the sample that has agglomerated into crystallites larger than 3.5 nm, using X-ray diffraction. These materials generally contain between 0.2 to 0.4 mass-% platinum on predominantly gamma-alumina support. This method can also be used for qualitatively determining the alumina types present in the sample.

Catalyst samples may be either fresh, spent or regenerated, as typical levels of carbon, sulfur and moisture associated with these samples do not interfere. Reforming catalysts containing less than 2% zeolitic materials may also be analyzed. Samples where the platinum has formed an alloy with other metals such as tin, rhodium, rhenium or iron cannot be analyzed by this method.