Analysis of Actinide Elements from Large Samples Henrieta Dulaiova Guebuem Kim Bill Burnett Florida State University and E. Philip Horwitz PG Research Foundation

Need for Large Volumes Achieve very low MDA's for environmental monitoring Specialized scientific studies often require large volumes to obtain necessary sensitivity, e.g., Am/Pu in seawater, global fallout in recent soils

Protocol for 10-g Samples Dissolution/ Leaching Diphonix HEDPA oxidation Resins: TRU TEVA UTEVA tracers 0.1M HCl-0.3M HF, AA "Matrix" 0.5M HEDPA H 3 PO 4 + actinides, Ln’s { one or more Separation Am, Pu, etc. alpha spectrometry ICP-MS “Fenton’s Reagent” H 2 O 2 + Fe 2+  OH + OH - +Fe 3+

Actinide Retention on Diphonix Resin Diphonix Resin high retention of actinides, Ln Low retention common ions Tolerate to HF

Elution: HEDPA Acid Dependency Curves Indicates that actinides should elute easily at concentrations ~0.5M

Elution of Am

Fenton’s Reagent Oxidation finished Treatment: 40 mL 0.5M HEDPA + 1 mL HNO mL H 2 O g Fe(NH 4 ) 2 (SO 4 ) 2  6H 2 O Temperature ~90 o C H 2 O 2 + Fe 2+  OH + OH - +Fe 3+

Actinide Separations TRU  Resin M HNO 3 2.5M HNO 3 /0.1M NaNO 2 2.5M HNO 3 9M HCl 4M HCl 4M HCl/TiCl M HCl 2.5M HNO 3 2.5M HNO 3 /0.1M NaNO 2 2.5M HNO 3 9M HCl 1M HCl 0.1M Ammonium Bioxalate Discard Am Pu Discard Th U Sample (3M HNO 3, 0.7M Al(NO 3 ) 3, FS, AA) Final clean-ups: Am/Ln on TEVA; U on UTEVA TRU  Resin tolerates high PO 4

10-g Samples: Yields Samples (n=7): 3 EML soils 2 IAEA sediments 2 Fe-rich soils 10-gram samples were leached with HNO 3 /HCl.

10-g Samples: Results Table 1: EML and IAEA intercomparison values.

Anal. Chem. Paper

Protocol for 50-g Samples Step10-gram*50-gram Leaching70 mL each: 6M HCl/8M HNO 3 4 hrs., 90 o C 150 mL each: 6M HCl/8M HNO 3 4 hrs., 90 o C Load Sol’n Add HF (0.5M), AA, adjust pH=1 ppt Fe(OH) 3 HCl, HF, AA, H 2 O to ~300 mL 2M HCl – 0.5M HF *Kim, Burnett, & Horwitz ( 2000)

Conditions - Diphonix Step10-gram50-gram Diphonix Column 1.2-cm diameter 10 mL resin same 13 mL resin Elution0.5M HEDPA 35 mL same 40 mL Oxid HEDPA* Fenton’s Reagent HNO 3 /H 2 O 2 /Fe 2+ same *Oxidation of HEDPA is done in a glass beaker on a hot plate – the reaction is complete in approx. 30 minutes

Conditions – Final Step10-gram50-gram TRU Column 0.6-cm dia, 5 mL ~15 mL HNO 3 - Al(NO 3 ) 3 -FS-AA 0.6-cm dia, 6 mL ~25 mL HNO 3 - Al(NO 3 ) 3 -FS-AA TEVA* (Am) Thiocyanate separation same Source Prep CeF 3 microprecipitation same *Am fraction purified of lanthanides on TEVA column to prevent thick source; Pu is processed directly after TRU

Spike Tests (50-g Soil) Am-241 and Pu-239 spiked samples. Matrix = HNO 3 /HCl leach of 50-g soil and sediment samples.

IAEA-300 (Baltic Sea Sediment) 50-g sample, leached with 6M HCl/8M HNO 3 Run through entire procedure… AnalyteYield % FSU mBq/g IAEA mBq/g* Am ± Pu-239/ ± Pu ±0.03~0.15# * recommended value/range # information value only

EML Soil 0009: 50-g sample, leached with 6M HCl/8M HNO 3 Run through entire procedure… AnalyteYield % FSU mBq/g EML mBq/g* Am ± Cm ±3~100 Pu-239/24049*15.3± Pu-23849*17.3±0.6-- *An additional 38% + ~15% recovered during 2 nd and 3 rd ppt; so total recovery through columns ~100%

Observations: 50-g Samples Solutions highly colored after HEDPA oxidation Load solution occasionally reacts with TRU. Resin – very strong oxidizing agent (CeIV?) Pu does not completely co- precipitate with CeF 3 – hold- back effect?

Color in Load Solutions Before loading…After ~20 minutes…

IAEA-300 Am 243 Am 241 Am

EML Soil 0009 Pu 238 Pu 239/240 P u 242 Pu

EML 9603 Pu (electro) 238 Pu 239/240 Pu 242 Pu

Summary Diphonix/HEPDA/oxidation process eliminates matrix Am/Pu separations work well via TRU  Resin Reaction on TRU indicates strong oxidizer present Hold-back phenomenon occurs during CeF 3 co-precipitation