Measurement of β-nuclides in various solutions using plastic scintillation microspheres

Scintillation cocktails cannot directly measure samples with extreme acidity or alkalinity in β-nuclide liquid scintillation analysis. Plastic scintillation microspheres (PSm), as a novel scintillation material, offer the potential to overcome these limitations by allowing direct mixing with a variety of solutions for measurement, particularly in challenging chemical environments.

This study evaluated the performance of PSm in various chemical environments, including four acids (nitric, hydrochloric, sulfuric, and phosphoric acids), an alkaline solution (NaOH), a high-salinity solution, and methanol. PSm formed stable mixtures with most solutions and exhibited excellent chemical stability in high-concentration NaOH, with minimal chemiluminescence interference. However, concentrated nitric and sulfuric acids caused chemical reactions with PSm, leading to discoloration and potential color quenching. Efficiency calibration was performed using ultrapure water, allowing for accurate measurement of ¹⁴C activity across different solutions with simple efficiency corrections.

The findings of this study highlight the advantages of PSm for β-nuclide measurement in a variety of complex chemical environments. PSm's stability in highly acidic, alkaline, and saline conditions makes it a promising tool for applications such as radioactive waste monitoring and pharmacokinetic research, providing a reliable and efficient alternative to conventional scintillation cocktails.