Microwave-assisted acid digestion (MAD) for the determination of radionuclides in contaminated soil

In this study, we developed a high efficiency sample pretreatment technique using microwave-assisted acid digestion (MAD) under a mixture of HNO₃-HCl-HF-H₂O₂ conditions, capable of leaching various radioactive nuclides from contaminated soil within 2 h. Our validation results using SRM 2709a soil standard material confirmed that when the MAD process was performed and then repeated, the chemical recovery rates of all 9 elements were consistently above 90%, demonstrating an outstanding leaching efficiency compared to conventional acid leaching (AL) methods. The activity of radionuclides obtained through AL were found to be underestimated compared to those obtained through MAD. We anticipate that the application of this technique for precise activity of radionuclides will contribute to cost savings in decommissioning waste management.