Rapid Determination of Actinides
in Vegetation Samples

AN-1406
Summary of Method U, Pu, Am and Cm are separated and concentrated from 5-10 gram vegetation samples.
Samples are muffled in zirconium crucibles 2-4 hours to destroy organic content. The residue is wet ashed with HNO3H2O2 and then fused with 15g NaOH at 600oC for ten minutes. The fusion cakes are dissolved in water, transferred to250mL centrifuge tubes and precipitated twice to facilitate matrix removal. Actinides are separated on stacked 2mL
cartridges of Eichrom TEVA, TRU and DGA resins. Actinides are
Figure 1. Sample Preparation
measured by alpha spectrometry following CeF3 microprecipitation
5-10g Vegetation sample +onto Eichrom Resolve® Filters. Chemical yields of tracers ranged
Tracers in zirconium crucible.
from 90-101% for 242Pu, 84-93% for 243Am, and 81-87% for 232U.
Measured values agreed to within 1-3% of reference values for Pu
isotopes, 3-9% for Am and Cm isotopes, and 2-15% for U isotopes
for 16 hour count times. A single operator can prepare batches of
12 samples for the measurement of actinides in less than 8 hours.
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 nitrate)
Lanthanum and Cerium Carriers (10mg/mL)
242Pu (or 236Pu if meas. Np), 243Am and 232U tracers
Oxalic acid/Ammonium oxalate
Hydrofluoric Acid (49%) or Sodium Fluoride
3.2M (NH4)2HPO4
2M Al(NO3)3
10% (w:w)TiCl3
Boric acid
Sodium Hydroxide
Sodium Nitrite
Denature Ethanol
Sulfamic Acid
Ascorbic Acid
Hydrogen Peroxide (30%)
Nitric Acid (70%)
Hydrochloric Acid (37%)
Deionized Water
1.25M Ca(NO3)2
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
Alpha Spectrometry SystemCentrifuge
Muffle Furnace
Hot Plate
Heat Lamp
Analytical BalanceVacuum Pump

Muffle at 600°C.
2 hours if 5g sample.
4 hours if 10g sample.
Wet ash on hotplate with 5mL
70% HNO3 and 5mL 30% H2O2.
Fuse samples with 15g NaOH at 600oC for 10 minutes.
Dissolve fusion cake with H2O andtransfer to 250mL centrifuge tube.
Add 10mL 3M HNO3 to crucible and heat to dissolve
residue. Transfer to the same 250mL centrifuge tube.
Add 125mg Fe, and 4mg La. Dilute to 180mL. Mix.
Add 4mL 1.25M Ca(NO3)2, 5mL 3.2M (NH4)2HPO4,and 10mL 10% TiCl3. Mix. Cool in ice bath for 10min.
Centrifuge at 3500rpm. Decant Supernate.
Dissolve precipitate in 150mL 1M HCl.
Add 1mg La, 1mL 1.25M Ca(NO3)3, 6mL
10% TiCl3. Mix. Add 20mL 49% HF.
Centrifuge at 3500rpm. Decant Supernate.

Dissolve precipitate in 5mL 3M HNO3-0.25M Boric acid,
7mL 70% HNO3, and 7mL 2M Al(NO3)3. Adjust valence
states with 0.5mL 1.5M Sulfamic acid, 10uL 50mg/mL
Fe carrier, and 1.25mL 1M Ascorbic acid. Mix.
Add 1mL 3.5M NaNO2 and 1.5mL 70% HNO3. Mix.Figure 2. Actinide Separation on TEVA - TRU - DGA*
(13) Strip Am and Cm from DGA with
(1) Precondition stacked 2mL(23) Draw vacuum until filter is dry.
10mL 0.25M HCl.
(24) Remove filter from funnel
TEVA, TRU, DGA withTEVA
assembly and mount filter on
10mL 3M HNO3.
(14) Rinse TRU cartridge with 15mL
(2) Load sample solution.
stainless steel planchet with 24M HCl-0.2M HF-0.002M TiCl3.
(3) Rinse sample tube withsided tape.
(15) Strip U from TRU with 15mL of5mL 6M HNO3.** AddTRU
0.1M ammonium bioxalate.
tube rinse to cartridges.
(16) Add 0.5mL 10% TiCl3 to U samples,(4) Rinse cartridges with 10mL
0.5mL 30% H2O2 to Pu, and 0.2mL
3M HNO3 .
DGA
30% H2O2 Am/Cm samples.
(5) Separate TEVA, TRU, andDGA cartridges.
(17) Add 50-100ug Ce carrier to all(6) Rinse TEVA cartridge with:samples. Mix well. Add 1mL 49%-10mL 3M HNO3
HF. Mix well. Wait 15-20 minutes.
-20mL 9M HCl( remove Th)(25) Dry filter under heat lamp for(18) Set up Resolve® Filter Funnel on-5mL 3M HNO33-5 minutes.
vacuum box.
(7) Strip Pu(Np) from TEVA with 20mL(26) Measure actinides by alpha(19) Wet filter with0.1M HCl-0.05MHF-0.01M TiCl3.
spectrometry.
3mL 80%(8) Rinse DGA with 8mL 0.1M HNO3.
ethanol followed(9) Place TRU cartridge above DGA .
by 3mL DI water.
(10) Strip Am/Cm from TRU onto DGA(20) Filter sample.
with 15mL 3M HCl.
(21) Rinse sample(11) Separate TRU and DGA. Set
tube with 5mL DITRU aside for U recovery.
water and add to(12) Rinse DGA with:filter.
-5mL 3M HCl(22) Rinse filter funnel with 3mL DI-3mL 1M HNO3
water and 2mL 100% ethanol.
-15mL 0.05M HNO3
*Radiostrontium may also be measured by adding a 2mL + 1mL Sr Resin cartridge below DGA and following separation
scheme in Eichrom application note AN-1405, “Rapid Determination of Sr in Vegetation Samples.”**Adding 50uL of 30% H2O2 to the tube rinse can help improve U recovery and decontamination in Pu/Np fractions.
Performance of Actinides in Vegetation Method
5 gram Samples
10 gram Samples
Reference Measured% Tracer
Reference Measured% Tracer
Nuclide Replicates (mBq/g)(mBq/g) % Bias Recovery Nuclide Replicates (mBq/g)(mBq/g) % Bias Recovery
238
238
629.4
30.1 + 3.7
2
27.4
28.1 + 0.4
2.4
101 + 6
2.6
90 + 15
Pu
Pu
239

Pu

6

101 + 6

239

Pu

2

32.8

32.4 + 0.9-1.2

90 + 15

1.0

93 + 7241

Am231.2

30.8 + 0.0-1.3

84 + 12

5.9 + 0.6

-6.1

93 + 7234

U241.641.3 + 1.3-0.7

81 + 1269.2

81 + 71787 + 7238

U243.242.0 + 0.3-2.8

81 + 1271.8

83 + 101687 + 7

56.8

57.0 + 4.8

241

648.0

48.5 + 4.6244

66.28

234

U6238

U

6AmCm

0.3

References
1) Sherrod L. Maxwell, Brian K. Culligan, Gary W. Noyes, “Rapid separation of actinides and radiostrontium invegetation samples,” J. Radioanal. Nucl. Chem., 286(1), 273-282 (2010).
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