Determination of Uranium Isotopic Ratio by ICP-OES Using Optimal Sensitivity Position Analysis

Area of Science:

• Analytical Chemistry
• Atomic Spectroscopy
• Isotope Analysis

Background:

• Inductively coupled plasma optical emission spectrometry (ICP-OES) typically requires high-resolution instruments for accurate uranium isotopic analysis due to minimal spectral shifts.
• Conventional ICP-OES instruments face challenges in distinguishing between ²³⁸U and ²³⁵U isotopes.

Purpose of the Study:

• To demonstrate that conventional ICP-OES can achieve highly accurate uranium isotopic analysis.
• To validate a mathematical procedure for enhancing ICP-OES performance in isotopic ratio determination.
• To compare ICP-OES results with those obtained by ICP-MS.

Main Methods:

• Application of the optimal sensitivity position (OSP) procedure for spectral analysis.
• Construction and subtraction of theoretical ²³⁸U spectra from measured calibration solution spectra.
• Identification of optimal measurement positions for ²³⁸U, ²³⁵U, and background signals.

Main Results:

• Conventional ICP-OES, when coupled with the OSP procedure, yields uranium isotopic analysis results comparable to ICP-MS.
• Optimal measurement positions were identified at 424.427 nm for ²³⁸U, 424.409 nm for ²³⁵U, and 424.390 nm for background.
• These optimal positions were found to be stationary, indicating the OSP procedure can be a routine mathematical approach.

Conclusions:

• The OSP procedure enables accurate uranium isotopic analysis using conventional ICP-OES, offering a cost-effective and simpler alternative.
• Mathematical analysis of spectra can significantly enhance the capabilities of ICP-OES for isotopic determination.
• This method provides a direct and highly accurate approach for determining uranium isotopic ratios.