Ion Chromatography Separation of Alkali, Alkaline Earth, Transition, Post-transition, Lanthanide, and Actinide Metal Cations in Waste Sludge

Trace radionuclides are present in concentrations of only a few hundred disintegrations-per-minute-per-milliliter in high-level radioactive waste samples. These radionuclides can be separated and analyzed using liquid scintillation counting and inductively coupled plasma–mass spectrometry. The authors developed an ion chromatography method to separate 31 cations in a single chromatographic run. Their method uses a linear gradient, a step gradient, and isocratic elution using four eluents in four separate eluent phases. The separation requires 45 min and has detection limits ranging from 0.1 to 5.0 ppm using spectrophotometric detection for nonradiative cations. This article presents the applications, limitations, interferences, precision, and accuracy of the method.