The determination of rare earth elements (REE) in spent catalyst samples from oil refinery is proposed. Three sample treatment procedures were tested, one without HF and two using different amounts of HF and boric acid. A microwave evaporation step to promote the dissolution of the REE fluorides was carried out. The medium containing 1.0 mL of HF and 8.0 mL of boric acid promoted the complete digestion. Studies were carried out using a reaction cell to overcome polyatomic interferences on four elements by inductively coupled plasma mass spectrometry (ICP-MS). Certified reference material, TDB-1, was used to evaluate the method accuracy applied to ten spent catalysts. The sample treatment is fast and promotes the complete digestion of the samples and the developed procedure led to proper accuracy for 14 of the 16 determined analytes. Recovery tests presented values between 87% and 101%.
rare earth elements; FCC spent catalyst; sample preparation; DRC-ICP-MS
