Simultaneous quantification and isotope ratio measurement of boron in uranium-silicon-aluminium compounds by inductively coupled plasma orthogonal acceleration time of flight mass spectrometry (ICP-oa-TOFMS) after its separation by pyrohydrolysis

•A clean and reagent-free pyrohydrolytic separation of boron from U-Si-Al compounds•Rapid release of boron due to in-situ accelerator formation•Simultaneous quantification and isotope ratio measurement of boron by ICP-oa-TOFMS•Low detection limit of boron•Improvement in precision of boron isotope ratio measurement

A simple and efficient procedure has been developed for the rapid and quantitative extraction of boron (B) from uranium-silicon-aluminium compounds, aided by generation of in-situ accelerator, employing pyrohydrolysis (PH) technique. The PH operating conditions like choice of carrier gas, heating time and sample mass were optimized for rapid and quantitative recovery of B. Inductively coupled plasma orthogonal acceleration time of flight mass spectrometer (ICP-oa-TOFMS) was utilized for the simultaneous determination of B content and its isotope ratio (10B/11B). The ICP-oa-TOFMS operating parameters like acquisition time, mass bias, long- and short-term stabilities were optimized and common analyte internal standardization (CAIS) chemometric technique was applied to improve both the accuracy and precision of 10B/11B ratio. The detection limit of the method for B was found to be 0.7 μg L- 1. The proposed method for B quantification was validated by an independent spectrophotometric technique. The accuracy on 10B/11B ratio measurement was established by carrying out PH of a synthetic mixture of U3O8 (free from B) and NIST SRM 951 followed by ICP-oa-TOFMS analysis of the distillate. XRD study of the sample before and after PH revealed the auto-acceleration ability of in-situ generated U3O8 phase on faster and efficient removal of analyte. The developed methodology was successfully applied for the analysis of five real samples of uranium silicide dispersed in aluminium matrix (U3Si2-Al) and three real uranium-silicon-aluminium alloy U(Al,Si)3 samples. The relative standard deviations (1σ) on B content and 10B/11B ratio in these samples were found to be within 3% and 0.16-0.27% respectively.