Fieldable Microfluidic Platform for Separation and Assay of U and Pu from Fission Samples in Environmental Matrices

An integrated microfluidic platform has been designed for in-field separation and assay of Pu and U from environmental samples. Separation of Pu and U from the sample matrix is accomplished by performing two sequential liquid-liquid extractions using 3D-printed supported liquid membrane (SLM) modules on the microfluidic scale. The initial extraction separates Pu and U from the bulk sample matrix, and the following extraction separates Pu from U for individual isotopic assay of the elements. Tested sample matrices were dissolved NIST SRM 2706 (New Jersey Soil), dissolved NIST SRM 365a (Portland Cement), and undiluted Atlantic Seawater. Chemistry is complete within 1 h of initializing the platform, and isotopic measurements from these matrices have been benchmarked with standardized sources. Typical yields are >90% and >40% for U and Pu, respectively. Generally, <1% of most fission product elements coextract with either U or Pu.