Study on the Spectral Interference of Thorium on Critical Elements and Rare Earths by CCD-based ICP-AES

Thorium is one of the key elements in the three-stage nuclear energy program of India. Due to the line-rich emission spectra of thorium, it is likely to interfere in the determination of trace metallic impurities by ICP-AES in a Th matrix. In this work, a systematic study was carried out to understand the spectral interference of Th on rare earths and all the critical elements (Ag, B, Ce, Eu, Gd, Dy, Sm, La, Nd, Er, Y, Ce, Lu, Pr, Yb) which have very stringent specification limits for the chemical quality control of Th-based fuels and nuclear materials. Due to the advancement of the capacitatively coupled detector (CCD) system, additional analytical lines of the analytes are available, which enhances the possibility of choosing relatively interference-free alternative analytical lines. The present study includes the development of an ICP-AES-based analytical method for the determination of Th, which is essential for calculating correction factors of interfered lines. The calibration curves established for four different analytical lines of Th (274.716 nm, 283.231 nm, 283.730 nm,