Nanoparticle-Assisted Uranium Extraction and Precise Isotopic Fingerprinting in Groundwater by TIMS

Area of Science:

• Environmental Science
• Analytical Chemistry
• Nuclear Geochemistry

Background:

• Groundwater isotopic screening for 234U/238U activity ratios is gaining importance.
• Accurate measurement of the low-abundance 234U/238U isotope ratio requires efficient uranium preconcentration.

Purpose of the Study:

• To develop an efficient uranium preconcentration method using polydopamine-coated magnetic nanoparticles (PDA@Fe3O4-NPs).
• To establish a precise and accurate method for measuring the 234U/238U isotope ratio using Thermal Ionization mass spectrometry (TIMS).

Main Methods:

• Uranium extraction from aquifer samples using PDA@Fe3O4-NPs, reducing analysis time by over 80%.
• Measurement of 234U/238U isotope ratio via TIMS with sequential ion current collection and internal normalization using the 238U/235U ratio.

Main Results:

• The novel method significantly improves precision and accuracy of 234U/238U measurements to better than 0.1%.
• Identified primary sources of uncertainty to enhance confidence in the correction methodology.

Conclusions:

• PDA@Fe3O4-NPs offer an efficient solution for uranium preconcentration in groundwater analysis.
• The developed TIMS methodology provides highly accurate 234U/238U isotope ratio determination with SI traceability.