A bioassay method for 237 Np in fecal samples

Abstract Fecal radiobioassay is a crucial and sensitive tool for estimating internal exposure and intake of actinides following radioactive or nuclear incidents. This study developed an analytical method to determine 237 Np in feces, utilizing TEVA resin for separation and purification, followed by detection with inductively coupled plasma mass spectrometry. By introducing 242 Pu as a chemical homologue tracer, which shares similar chemical behaviour with 237 Np in the tetravalent state, we effectively monitored the chemical recovery of the target nuclide. We systematically optimised sample pretreatment steps, such as calcination temperature and redox conditions, along with key parameters in the TEVA resin separation process, including sample acidity and elution volume, significantly enhancing the separation and purification efficiency of 237 Np. Experimental results indicated average chemical recoveries of 79% for 237 Np and 82% for 242 Pu. Furthermore, multiple repeated experiments effectively verified the method’s accuracy and reliability. The established analytical procedure is practical and yields stable results, providing robust technical support for accurately quantifying 237 Np in feces, with significant applications in radiation protection and public health monitoring.