Smelting-grade alumina certificate specifications include elemental impurities to be monitored, including sodium, ironIron, nickel, and more. The Supplier-User Agreement depends on shared standards for the specifications which require both parties to be capable of analyzing aluminaAlumina, plus ability to refer to a third, capable laboratory, for arbitration. For this, using internationally developed ISOInternational Organization for Standardization (ISO) standards for analysis is critically important. The paper discusses determination of element impurity levels by X-ray fluorescence, XRF. In Part 1 ISOInternational Organization for Standardization (ISO) standard work is presented. For XRF-analysis, two smelting-grade aluminaAlumina methods are in use: ISOInternational Organization for Standardization (ISO) 23201 based on the preparation as glass beads and a new ISOInternational Organization for Standardization (ISO) standard based on pressed pellets or tablets (ISOInternational Organization for Standardization (ISO), in development). Part 2 is a discussion on ensuring comparable analysis going forward. For XRF, agreement on the selection of calibration materials is crucial for setting good specifications. Historically, for a pressed pellets method, the ALCAN-ALU calibration set is established among suppliers and users, and this calibration should be preserved.