Ammonium bioxalate

Hill et al. used ICP-MS and FI with TRU-Resin column separations for determination of U and Th in natural waters.134 High analyte recoveries were found even in waters with high dissolved organic matter, which normally presents a problem if samples are concentrated using typical ion-exchange or chelating resins. Samples on the TRU-Resin column were washed with nitric acid as usual and eluted in ammonium bioxalate. 

The TRU-Resin column served to preconcentrate the actinide of interest from urine or digested urine samples. Methods were developed for the analysis of Pu in urine, Am in urine, as well as U and Th in urine. After column washing, the actinides were eluted in a single step, using ethylenediaminetetraacetic acid for Am or Pu, and ammonium bioxalate for the U/Th determinations. Column reusability was quite limited if urine samples were not digested first. 

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