Separation of actinides at ultra-trace level from urine matrix using extraction chromatography-inductively coupled plasma mass spectrometry

The determination of trace level actinides in a urine matrix was evaluated on the chromatographic column packed with TRU resin for separation. The chromatographic system was coupled on-line to the inductively coupled plasma mass spectrometer (ICP-MS) for pre-concentration and separation of uranium, thorium, plutonium, neptunium, and americium. 3 M nitric acid was employed to remove the matrix ions, which at the same time pre-concentrated the actinides to obtain detection limits in the range of 0.01-2 pg mL(-1). Different concentrations of HCl and oxalic acid were used to sequentially elute the five actinides. The separation took ca. 25 minutes, with no sample preparation required. Linear dynamic range, precision of the measurement, and lifetime of the column were studied to evaluate the proposed method. The method of on-line separation and pre-concentration of actinides in urine offers major improvements to routine procedures for bioassay analysis.