Determination of rhodium by thermal neutron activation analysis using g-ray spectrometry

Trace amounts of rhodium have been determined by thermal neutron activation analysis using both destructive and non-destructive methods. With a neutron flux of 10¹² n cm^-2 sec^-1 the lower limits of detection are about 0.1 μg and 0.01 μg, respectively. A rapid sodium-peroxide fusion followed by a pyridine extraction was used in the destructive method to separate the 4.4-mm ^104mRh from its matrix. The 44-sec¹⁰⁴Rh was used in the non-destructive method. Both radioactive isomers were measured by γ-ray spectrometry with a multichannel pulse height analyzer. The average time required per non-destructive analysis was 7 min while the chemical method averaged 20 min.