TEVA™ resin

In 1994, Dadfarnia and McLeod described the analysis of uranium in surface waters and sea water using a simple FI system with an alumina column for preconcentration.77 Species eluted from this column were delivered to an ICP-MS as the detector. Also in 1994, Hollenbach et al. described the automation of extraction chromatographic methods based on TRU-Resin and TEVA-Resin to separate and preconcentrate U, Th, and Tc from soil samples, using ICP-MS for detection.49125 In 1996, Aldstadt et al. described the use of FI and extraction chromatography using TRU-Resin to determine U in environmental samples by ICP-MS.78... 

Aliquat 336 TEVA-Resin "Tc determination in soil samples using extraction chromatography in FI system to separate and concentrate ICP-MS 49... 

Aliquat 336 TEVA-Resin "Tc determination in SI system using stopped-flow detection for nuclear waste On-line liquid scintillation 44... 

Aliquat 336 TEVA-Resin "Tc separated on-line using renewable separation column to release resin with 99Tc rather than elute from the column Off-line liquid scintillation on resin 83... 

Aliquat 336 TEVA-Resin "Tc sensing in water using column containing mixture of TEVA-Resin particles and scintillating plastic beads Radiometric column sensor 96,97... 

Pu determinations in sediments using on-line tandem Sr-Resin and TEVA-Resin columns in PrepLab system SF-ICP-MS 56... 

Hollenbach et al. captured "Tc from standards or soil sample digestates on a TEVA-Resin column for on-line purification and preconcentration prior to ICP-MS determination.49 A wash solution of 0.5 M HN03 was used to remove interferences prior to elution with 8 M HN03 solution. A Re isotope, which behaves similarly to pertechnetate on TEVA-Resin, was used as an internal standard. Recoveries from the column varied from 97 to 99.5%, and columns could be reused over a hundred times. The use of the on-line column separation reduced detection limits by 10-fold and alleviated matrix and isobaric interferences compared to direct sample injection. This pioneering study adapted FIAS-200 and FIAS-400 FI systems to perform sample injection and extraction-chromatographic separations upstream from the ICP-MS. 

FIG U RE 9.4 Extraction chromatographic separation of "Tc(VII) from other fission products in the sample using a sequential injection separation system with a TEVA-Resin column. The signal for the "Tc is shown in the vertically expanded trace in the inset. (Reproduced from Egorov, O. B., O Hara, M. J., Ruzicka, J., and Grate, J. W., Anal. Chem., 70, 977-984, 1998. With permission.)... 

In subsequent work, it was shown that a renewable separation-column approach could be used to capture and purify "Tc on a TEVA-Resin column set up between a pair of 2-position valves, as shown in Figure 9.6.83 After loading the sample and washing away interferences, the separation material was released from the column and delivered downstream to a collection vial. Scintillation cocktail was added to the vial off-line and the "Tc was determined radiometrically. In this approach, there is no need to elute the "Tc with strong acid, and a fresh suspension of separation material is delivered to the column body for each sample. 

Actinides can be separated from matrix elements, other radionuclides, and each other using extraction-chromatographic materials such as TEVA-Resin, TRU-Resin, and UTEVA-Resin. The capacity factors for various actinides on these resins, as a function of nitric or hydrochloric acid concentrations are shown in Figures 9.11 and 9.12.30 31127 Elution peaks or collected fractions from column separations can be... 

TEVA-Resin is an extraction-chromatographic material based on Aliquat 336, which is a liquid quaternary ammonium salt, as described previously in connection with "Tc separations.30 It acts as a strongly basic anion-exchange material, retaining tetravalent actinides from 2-4 M HN03 solutions as anionic nitrato complexes (see Figure 9.11). Am(III), Np(V), and U(VI) are much less retained. The extraction... 

Epov et al. used TEVA-Resin in the isolation of Pu for the analysis of Pu in the presence of much higher U concentrations, using the FIAS-400 fluidic system.50 These authors also selected ascorbic acid to adjust the valence state of Pu to Pu(IV). Samples were loaded and washed in 4 M HN03, removing the trivalent actinides. Elution with 1 M HN03 removed most U and some Th. Finally, 0.02 M HC1 was... 

Sample preparation also includes certain matrix separation steps (e.g., by ion exchange, extraction chromatography and others), analyte enrichment (by co-precipitation and also ion exchange, e.g., Pu separation is performed using TEVA resin ) and preconcentration steps (e.g., by evaporation of solvent) off line or on line by high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) in order to improve the detection limits and avoid disturbing interference problems in ICP-MS. 

An ultratrace level Pu isotope analysis was performed in MC-ICP-MS by Becker et al. (2004) after separation on TEVA resin and enrichment of Pu from 100 L lake water fi-om the Sea of Galilee. Studies of the separation procedure for 2.1 pg Pu spiked to 100 L of lake water have resulted in a yield of 62%. The detection limit for Pu measurement by MC-ICP-MS was 3 X 10 ° g/mL. Pu was detected inlOOLlake water ataconcentration level of about 3.6 x 10 g/mL. Hence, the measured Pu/ Pu isotope ratio by MC-ICP-MS of 0.17 is a clear evidence of plutonium contamination fi om the global nuclear fallout in the 1960s. 

TEVA resin Selective resin Tc, actinides (IV), Am, lanthanides Nitric acid, hydrochloric acid... 

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