Abstract：The conditions for determination of lanthanum, cerium and yttrium in titanium alloys by inductively coupled plasma atomic emission spectrometry (ICP-AES) was investigated and thus the analytical method was established. The sample was dissolved in sulfuric acid or sulfuric acid-hydrofluoric acid. The spectral lines with wavelengths of 398.852 nm, 394.274 nm and 371.092 nm were selected as the analytical lines for lanthanum, cerium and yttrium, respectively. The matrix effect on the determination was eliminated by the matrix matching method. The linear ranges (mass fraction) of the calibration curves for lanthanum, cerium and yttrium were 0.001 %-0.030 %, 0.005 %-0.030 % and 0.001 %-0.030 %, respectively. The linear correlation coefficients were 0.999 9. The detection limits were 0.003 μg / mL for lanthanum, 0.015 μg/mL for cerium and 0.001 μg/mL for yttrium. The dissolution of sample by sulfuric acid and sulfuric acid-hydrofluoric acid was compared and the results showed that both the methods achieved accurate determination of lanthanum, cerium and yttrium, but the method for dissolution of sample with sulfuric acid-hydrofluoric acid was faster and therefore increased the analysis efficiency. The precision and standard addition tests were conducted by adding different amounts of lanthanum, cerium and yttrium into titanium alloys samples containing no lanthanum, cerium and yttrium and the RSD values for lanthanum, cerium and yttrium were found to be less than or equal to 1.7 %, 7.3 % and 0.59%, respectively, and the recoveries were found to be between 92 % and 100 %. The method was applied to the determination of yttrium and lanthanum in titanium alloy samples and the results were consistent with thosed obtained by ICP-MS. The method was applied to the determination of cerium and yttrium in titanium alloy reference materials and the results were consistent with the certified values.
