This standard specifies a method for the determination of iridium content in platinum and palladium alloys. It is suitable for PtIr and PdIr alloys, and the determination range is 5% to 30%. The method first uses muriatic acid and hydrogen peroxide to seal chlorination to dissolve the sample, and separates palladium with active copper powder. In muriatic acid medium, iridium is oxidized to tetravalent iridium using sodium chlorate. In muriatic acid and sulfuric acid medium, iridium (IV) is titrated by current using ferrous sulfate standard titration solution, and the selected potential is + 0.5 V to indicate the end point. The standard complies with the relevant provisions of YS/T 371.