AN-1413

Rapid Determination of Actinides
in Emergency Water Samples

Summary of Method Uranium, Plutonium and Americium-Curium are separated and concentrated from up to400mL water samples using calcium phosphate precipitation. The precipitate is dissolved in nitric acid and aluminum
nitrate. Actinides are separated from matrix impurities and potentially interfering radionuclides in the sample using 2mL
cartridges of Eichrom TEVA and TRU Resins. Actinides are measured by alpha spectrometry following source
preparation by cerium fluoride microprecipitation onto Eichrom Resolve® Filters. Chemical yields are determined byrecovery of 232U, 243Am, and 242Pu (or 236Pu, if measuring 237Np) tracers. Typical chemical recoveries are >90%. A single
operator can complete the separation method for batches of 12-24 samples in as little as 4-5 hours.
Reagents
TEVA Resin, 2mL Cartridges (Eichrom TE-R50-S)
TRU Resin, 2mL Cartridges (Eichrom TR-R50-S)
Ammonium Hydroxide (listed as 28% NH3 or 56% NH4OH)
Nitric Acid (70%)
Hydrochloric Acid (37%)
Hydrofluoric Acid (49%) or Sodium Fluoride
Deionized Water
Iron Carrier (50mg/mL)
Cerium Carrier (1mg/mL)
1.25M Ca(NO3)2
3.2M (NH4)2HPO4
2M Al(NO3)3
10% (w:w) TiCl3242Pu (or 236Pu if meas. Np), 243Am and 232U tracers
Oxalic acid/Ammonium oxalate
Sulfamic Acid
Ascorbic Acid
Sodium Nitrite
Denatured Ethanol
Equipment
Vacuum Box (Eichrom AR-24-BOX or AR-12-BOX)
Cartridge Reservoir, 20mL (Eichrom AR-200-RV20)
Inner Support Tubes-PE (Eichrom AR-1000-TUBE-PE)
Yellow Outer Tips (Eichrom AR-1000-OT)
Resolve Filters in Funnel (Eichrom RF-DF25-25PP01)
50mL and 250mL Centrifuge Tubes
Centrifuge
Analytical Balance
Alpha Spectrometry System
Vacuum Pump

Figure 1. Sample Preparation
400mL water + Tracers,
2mL 1.25M Ca(NO3)3,5mL 3.2 M (NH4)2HPO4.
Mix WellAdjust to pH 10 with NH4OH.
Mix Well.
Centrifuge 3500 rpm, 10 min.
Dissolve precipitate in 8mL 6M
HNO3 and 8mL 2M Al(NO3)3.
Cool to room temperature.

DecantSupernate
To Waste

Adjust valence states of actinides by adding
the following reagents in the order listed(mix between additions):
0.5mL 1.5M Sulfamic acid, 10uL 50mg/mLFe carrier, 1.25mL 1M Ascorbic acid,1mL 3.5M NaNO2, and 1.5mL 70% HNO3.
Load Solution toResin Separation

Figure 2. Actinide Separation on TEVA - TRU*
(1) Precondition stacked 2mL
TEVA-TRU with 10mL
3M HNO3.
(2) Load sample solution.
(3) Rinse sample tube with
5mL 6M HNO3. Add tube
rinse to cartridges.**(4) Rinse cartridges with 5mL
3M HNO3.
(5) Separate TEVA and TRU
cartridges.

TEVA(11) Add 0.5mL 30% H2O2 to Pu and0.2mL 30% H2O2 to Am/Cmsamples for additional U decon.
during CeF3 ppt.

TRU(12) Add 0.5mL of 10% TiCl3 to each U
sample for CeF3 ppt.
(13) Add 50-100ug Ce carrier to all
samples. Mix well. Add 1mL 49%
HF. Mix well. Wait 15-20 minutes.

(14) Set up Resolve® Filter Funnel on(6) Rinse TEVA cartridge with:vacuum box.
-15mL 3M HNO3(15) Wet filter with
-20mL 9M HCl( remove Th)
3mL 80%-5mL 3M HNO3
ethanol followed(7) Strip Pu(Np) from TEVA with 20mLby 3mL DI
0.1M HCl-0.05MHF-0.01M TiCl3.
water.
(8) Strip Am/Cm from TRU with15mL 4M HCl. Dilute to 30mL
prior to CeF3 ppt.
(9) Rinse TRU with 15mL 4M HCl0.2M HF. (Th removal)(10) Strip U from TRU with 15mL
0.1M ammonium bioxalate.

(16) Filter sample.

(19) Draw vacuum until filter is dry.
(20) Remove filter from funnel
assembly and mount filter on
stainless steel planchet with
2-sided tape.

(21) Dry filter under heat lamp for
3-5 minutes.
(22) Measure actinides by alphaspectrometry.

(17) Rinse sampletube with 5mL DI
water and add tofilter.
(18) Rinse filter funnel with 3mL DI
water and 2mL 100% ethanol.

*Strontium may also be measured by adding a 2mL Sr Resin Cartridge below DGA and following the separation schemein Eichrom application note AN-1411, “Rapid Determination of Sr in Emergency Water Samples.”**Adding 50uL of 30% H2O2 to the 6M HNO3 tube rinse can help improve U recoveries and decontamination in the Pu/Npfraction.

References
1) Sherrod L. Maxwell, Brian K. Culligan, “Rapid separation method for emergency water and urine samples,” J.
Radioanal. Nucl. Chem., 279(3), 901-907 (2009).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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