Pyrosulfate fusion vs. TEVA / TRU forcing the issue Shane Knockemus U.S. EPA / NAREL Montgomery, AL November 11, 2002

Advantages / disadvantage / goal Advantages of fusion – Achieves total sample dissolution (including refractory material) of nearly any type of sample. – Rapid and vigorous. – Not many reagents consumed. – Insures homogeneity between tracer and sample. Disadvantage of fusion – Introduces large amount of sulfate ions into sample matrix, which may effect some separation processes. Goal: To achieve a reliable separation process for Am, Pu, Th, and U when analyzing a sample put into solution by pyrosulfate fusion.

Potassium fluoride / pyrosulfate fusion gram soil in Pt dish 1 g KF, 1.3 g KHF 2 …….FUSE 3 mL 18 M H 2 SO 4, 2 g Na 2 SO 4 …….FUSE

TEVA / TRU Separation Scheme

Experiment 1 flowchart cake HNO 3 / Al(NO 3 ) 3 TEVA / TRU –

Poor Pu / Th separation (exp.1)

Experiment 1 Results AnalysisResolution / separation Tracer YieldAnalyte Yield AmGood U PuPoor NA * ThNAPoorNA

Experiment 2 flowchart cake 16 M HNO 3 HNO 3 / Al(NO 3 ) 3 TEVA / TRU

Pu spectrum with Th contamination (exp. 2)

Experiment 2 Results AnalysisResolution / separation Tracer yieldAnalyte yield AmPoor NA UGood PuPoor * NA * ThNAPoorNA

Influence of Matrix Constituents on TEVA Find a way to eliminate the SO 4 -2 introduced during the fusion before the sample is loaded onto TEVA / TRU.

Experiment 3 flowchart cake HCl Calcium phosphate pptn HNO 3 / Al(NO 3 ) 3 TEVA / TRU

Am and U spectra (exp. 3)

Experiment 3 Results AnalysisResolution / Separation Tracer yieldAnalyte yield AmGood U PuPoor NA * ThNAPoorNA

Experiment 4 flowchart cake HCl BaSO 4 pptn K + EDTA Titanous hydroxide pptn HNO 3 / Al(NO 3 ) 3 TEVA / TRU

Th spectra (exp. 4)

Clean Pu spectrum (exp. 4)

Experiment 4 Results AnalysisResolution / separation Tracer YieldAnalyte yield AmNAPoorNA U**NA PuGood ThGood **Uranium recovery was 0% because there was no valence adjustment prior to BaSO 4 coprecipitation

Experiment 5 This experiment was carried out the same as experiment 4, but instead of a titanous hydroxide precipitation, a calcium phosphate precipitation was used. Prior to the BaSO 4 precipitation U +6 was reduced to U +4 with hydrazine and TiCl 3

Spectra experiment 5

Experiment 5 Results AnalysisResolution/ separation Tracer YieldAnalyte Yield AmNAPoorNA UGood PuGood ThGood

Experiment 6 flowchart cake HCl / HF diphonix destroy resinHNO 3 / Al(NO 3 ) 3 TEVA / TRU

Usefulness of diphonix Diphonix will help separate the sample from certain matrix constituents introduced to the sample as part of the digestion process. Sample loaded in 1 M HCl / 0.5 M HF. Actinides stick, while troublesome ions not be sorbed by the resin.

Loading of sample on diphonix 0.3 g of diphonix resin packed into column Resin charged with 5 mL 1 M HCl Cake dissolved in 30 mL 1 M HCl / 0.5 M HF Sample loaded onto column Column rinsed with 5 mL 1 M HCl Resin destroyed by charring with H 2 SO 4 and HNO 3, followed by oxidation of organics with HClO 4

Spectra of experiment 6

Experiment 6 Results AnalysisResolution / separation Tracer YieldAnalyte Yield AmGood U PuGood ThGoodBetterNA

Evaluation of data for exp. 6 NuclideMAPEP value(pCi/g) Measured activity Measured / known Am Pu U U MAPEP did not have certified values for Th nuclides

Final tally of experiments (hit or miss) Exp. #AmPuUTh 1HITMISSHITMISS 2 HITMISS 3HITMISSHITMISS 4 HITNA*HIT 5MISSHIT 6