Rapid Determination of Actinides
in 100g Emergency Food Samples

AN-1426
Summary of Method U, Pu, Np, Am and Cm are separated and concentrated from 100gram food samples.
Samples are muffled at 600°C in zirconium crucibles 2 hours to destroy organic content. The residue is wet ashed with
HNO3-H2O2 and then fused with 15g NaOH at 600°C for ten minutes. The fusion cakes are dissolved in water,transferred to 250mL centrifuge tubes and precipitated sequentially with hydrous titanium oxide and lanthanum fluoride
to facilitate matrix removal. Actinides are separated on stacked 2mL cartridges of Eichrom TEVA, TRU and DGA resins.
Actinides are measured by alpha spectrometry following CeF3 microprecipitation onto Eichrom Resolve® Filters.
Chemical yields of tracers ranged from 93-98% for 236Pu, 85-93% for 243Am, and 78-89% for 232U. Measured values
typically agreed to within 10% of reference values. Sample preparation for batches of 12 samples can be completed bya single operator in <16hours. Alpha spectrometry count times will depend on detection limit and data quality objectives.
Reagents
TEVA Resin, 2mL Cartridges (Eichrom TE-R50-S)
TRU Resin, 2mL Cartridges (Eichrom TR-R50-S)
DGA Resin, 2mL Cartridges (Eichrom DN-R50-S)
Iron carrier (50mg/mL Fe, as ferric iron nitrate)
242Pu (or 236Pu if meas. Np), 243Am and 232U tracers
Oxalic acid/Ammonium oxalate
La and Ce carriers (1mg/mL)
Deionized Water
1.25M Ca(NO3)2
3.2M (NH4)2HPO4
2M Al(NO3)3
10% (w:w) TiCl3
HNO3 (70%)
HCl (37%)
NaOH
HF (49%) or NaF
Boric acid
H2O2 (30%)
NaNO2Denatured ethanolSulfamic Acid
Ascorbic Acid
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
250mL Zirconium crucibles with zirconium lids
Stainless Steel Planchets with adhesive tape
Alpha Spectrometry SystemCentrifuge
Muffle Furnace
Analytical Balance
1L Glass Beakers
Vacuum Pump
Heat Lamp

Figure 1. Sample Preparation
100g Food sample + tracers in 1L glass beaker
Muffle at 550°C for 12 hours.
Transfer ash to Zr-crucible. Rinse beaker with 10mL 70%
HNO3 and 10mL 30% H2O2.Transfer to crucible. Wet ash.
Fuse samples with 15g NaOH at 600°C for 10minutes.
Dissolve fusion cake with H2O. Transfer to 250mL c-tube.
Add 10mL 3M HNO3 to crucible. Heat to dissolve
residue. Add to same c-tube.
Add 125mg Fe and 5mg La to c-tube. Dilute to 180mL.
Add 4mL 1.25M Ca(NO3)2, 5mL 3.2M (NH4)2HPO4,5mL 10% TiCl3. Mix. Cool in ice bath for 10min.
Centrifuge at 3500rpm. Decant Supernate.
Partillay dissolve precipitate in 60mL 1M HCl.
Some solids will remain. Dilute to 170mL.
Add 1mg La, 1mL 1.25M Ca(NO3)3,3mL 10% TiCl3. Mix. Add 20mL 49% HF.
Centrifuge at 3500rpm. Decant Supernate.
Dissolve precipitate in 5mL 3M HNO3-0.25M Boricacid, 7mL 70% HNO3, and 7mL 2M Al(NO3)3.
Fix valence states. Mix between each addition of: 0.5mL
1.5M sulfamic acid, 10uL 50mg/mL Fe, 1.5mL 1M
ascorbic acid, 1mL 3.5M NaNO2, 1.5mL 70% HNO3.

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

(12) Rinse DGA cartridge sequentially
with: -5mL 3M HCl
TEVA-3mL 1M HNO3-15mL 0.05M HNO3(13) Strip Am and Cm from DGA with
TRU 10mL 0.25M HCl.
(14) Rinse TRU cartridge with 15mL
4M HCl-0.2M HF-0.002M TiCl3 .
DGA (15) Strip U from TRU with 15mL of0.1M ammonium bioxalate.

(22) Rinse filter
funnel with 3mL
DI water and 2mL
100%ethanol.
(23) Draw vacuum
until filter is dry.

(24) Remove filter fromfunnel assembly andmount filter on stainless(16) Add 0.5mL 10% TiCl3 to U samples,steel planchet with 2-sided tape.
0.5mL 30% H2O2 to Pu, and 0.2mL
30% H2O2 to Am/Cm samples.

(6) Rinse TEVA cartridge with:-10mL 3M HNO3-20mL 9M HCl-5mL 3M HNO3
(7) Strip Pu (and Np) from TEVAcartridge with 20mL 0.1M HCl0.05MHF-0.01M TiCl3.

(17) Add 50-100ug Ce carrier to allsamples. Mix well. Add 1mL 49% HF.
Mix well. Wait 15-20 minutes.

(8) Rinse DGA cartridge with 10mL
0.1M HNO3.
(9) Place TRU cartridge above DGA.
(10) Strip Am/Cm from TRU onto
DGA with 15mL 3M HCl .
(11) Separate TRU cartridge fromDGA cartridge.

(18) Set up Resolve® Filter Funnel onvacuum box.
(19) Wet filter with 3mL 80% ethanol
followed by 3mL DI water.
(20) Filter sample.
(21) Rinse sample tube with 5mL DI
water and add to filter.

(25) Dry filter under heat lamp for
3-5 minutes.
(26) Measure actinides by alpha
spectrometry.

*Adding 50uL 30% H2O2 to tube rinse can improve Uranium recoveries and decontamination in Pu(Np) fractions.
Method Performance 100g Apple Samples (16 hr count times)
AnalyteAnalyte% Tracer (mBq/g)(mBq/g)Sample Replicates Analyte Tracer Recovery Reference Measured % Bias
238
236
Apples50.29
0.30 + 0.02
3.1
78 + 8Pu
Pu
5239

Pu

236

Pu

78 + 80.36

0.37 + 0.05

4.05237

Np236

Pu

78 + 80.37

0.36+ 0.02

-3.3

5241

Am

243

Am

76 + 30.25

0.25 + 0.02

-2.3

5244

243

76 + 30.35

0.41 + 0.03

165238U

232

71 + 50.57

0.56 + 0.04

-1.4

5234

U

232

71 + 50.59

0.58 + 0.05

-2.7CmAmUUReferences1) Sherrod L. Maxwell, Brian K. Culligan, Angel Kelsy-Wall, Patrick J. Shaw, “Rapid separation of actinides and inemergency food samples,” J. Radioanal. Nucl. Chem., 292(1), 339-347 (2011).
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