Rapid Determination of Pu, Np,
Am and Cm in 100g Soil Samples

AN-1431
Summary of Method Pu(Np) and Am-Cm are separated and concentrated from 100-200 gram soil samples.
Samples are muffled at 550°C to destroy organic content and wet ashed and leached with HNO3 and HCl. The filteredleachates are evaporated to dryness and fused with NaOH in Zr crucibles. Sequential precipitations facilitate matrix
removal. Actinides are separated on stacked 2mL cartridges of Eichrom TEVA, TRU, and DGA resins. Native rare earths
from the samples are removed from Am-Cm using TEVA Resin and ammonium thiocyanate. Actinides are measured byalpha spectrometry following CeF3 microprecipitation onto Eichrom Resolve® Filters. Chemical yields of tracers ranged
from 93-98% for 236Pu and 85-93% for 243Am. Measured values
Figure 1. Sample Preparation
typically agreed to within 10% of reference values. Sample
Dry 100-200g soil at 110°C. Blend and Size.
preparation for batches of 12 samples can be completed by asingle operator in <8 hours.
Aliquot sample to 1L glass beaker. Add tracers.
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), and 243Am tracers
La carrier (10mg/mL) Ce carrier (1mg/mL)
Deionized Water
2M Al(NO3)3
10% (w:w) TiCl3
HNO3 (70%)
HCl (37%)
NaOH
HF (49%) or NaF
Boric acid
H2O2 (30%)
NaNO2Denatured ethanol
Sulfamic Acid
Ascorbic Acid
Ammonium Thiocyanate
Formic 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)
1L and 600mL Glass beakers
250mL Zirconium crucibles with lids
Stainless Steel Planchets with adhesive tape
Alpha Spectrometry System
50mL and 250mL Centrifuge Tubes
25mm 0.45um filters
Centrifuge
Heat Lamp
Muffle Furnace
Hot Plate
Analytical Balance
Vacuum Pump

Muffle at 550°C for 4 hours.
Cool. Add 75mL 70% HNO3 and 25mL 37% HCl.
Heat to dryness on hotplate.
Add 75mL 70% HNO3. Warm sample. Transfersolids and liquid to 250mL centrifuge tube.
Add 25mL 70% HNO3 to beaker. Warm beaker.
Transfer solids and liquid to 250mL centrifuge tube.
Centrifuge 3500 rpm, 10 min.
Filter leachate through 25mm 0.45um filter.
Transfer leachate to 600mL beaker.
Add 25mL 70% HNO3 to solids. Mix. Centrifuge.
Filter leachate into same 600mL beaker. Repeat once.
Add 25mL warm 4M HCl to solids. Mix. Centrifuge.
Filter leachate into same 600mL beaker. Repeat once.
Evaporate supernate in 600mL beaker to dryness.
Wet ash with 15mL 70% HNO3 to dryness. Repeat once.
Transfer solids to 250mL Zr crucibles. Rinse beakers with 70%HNO3. Transfer to same crucible. Heat crucibles to dryness.
Add 20g NaOH to each crucible. Fuse at 600°C for 20min.
Dissolve fusion cakes with water. Transfer to 250mL c-tubes.
Rinse crucibles with 10mL 3M HNO3. Heat to dissolve residue.
Transfer to same c-tube. Continue to precipitation steps.

Figure 2. Actinide Separation on TEVA - TRU - DGA and Source Preparation
Dilute samples to 180mL.
Add 7mg La and 20mL 10% TiCl3.
Mix. Cool to room temperature.

(4) Rinse cartridges w/ 5mL 6M HNO3.
(5) Separate TEVA from TRU-DGA.

(20) Add 50ug Ce carrier to allsamples. Add 0.5mL 30% H2O2 to Pu
samples and 0.2mL 30% H2O2 toAm/Cm samples. Mix. Add 1mL 49%
HF. Mix. Wait 15-20 minutes.

(6) Rinse TEVA with:-10mL 6M HNO3
Centrifuge 3500 rpm. 5min.
-10mL 3M HNO3
Decant supernate-20mL 9M HCl (Th removal)(21) Set up Resolve® Filter Funnel on-5mL 3M HNO3vacuum box.
Partially dissolve in 60mL 1.5M HCl.
(7) Strip Pu from TEVA with 20mL
Solids will remain. Dilute to 170mL.
(22) Wet filter with 3mL 80% ethanol
0.1M HCl-0.05M HF-0.03M TiCl3.
followed by 3mL DI water.
Add 2mg La and 10mL 30% H2O2. Mix.
(8) Rinse TRU-DGA with 15mL 4M HCl.
Add 22mL 49% HF. Mix.
(23) Filter sample.
(9) Discard TRU cartridge.
(10) Rinse DGA w/ 20mL 0.05M HNO3. (24) Rinse sample tube with 5mL DI
Centrifuge 3500 rpm. 5min.
(11) Strip Am/Cm w/ 10mL 0.25M HCl. water and add to filter.
Decant supernate(12) Add 2mL 70% HNO3 + 50uL 10% (25) Rinse filter funnel with 3mL DI
Dissolve solids in 5mL 3M HNO3H2SO4 to Am/Cm. Evaporate to dryness. water and 2mL 100% ethanol.
0.25M Boric acid, 6mL 7M HNO3, and (13) Ash to dryness with 3mL 70%(26) Draw vacuum until filter is dry.
7.5mL 2M Al(NO3)3. Warming samples HNO3 + 2mL 30% H2O2.
(27) Remove filter from funnel
can improve dissolution.
(14) Dissolve Am/Cm in 5mL
assembly and mount filter on
4M NH4SCN-0.1M Formic acid.
Cool samples to room temp. Fix
valence by adding: (mix between steps) (15) Precondition 2mL TEVA with 5mL
4M NH4SCN-0.1M Formic acid.
-0.5mL 1.5M sulfamic acid(16) Load Am/Cm on TEVA.
-40uL 50mg/mL Fe carrier-1.5mL 1M ascorbic acid (Wait 3 min) (17) Rinse Am/Cm beaker with 5mL
4M NH4SCN-0.1M Formic acid.
-1mL 3.5M NaNO2
Add to TEVA.
(1) Precondition 2mL TEVA, TRU,
DGA cartridges with 10mL 8M HNO3. (18) Rinse TEVA w/ 10mL 1.5M
NH4SCN-0.1M Formic acid.
(2) Load Sample.
(3) Rinse c-tube with 5mL 6M HNO3.* (19) Strip Am/Cm from TEVA with
Add to stacked cartridges.
20mL 1M HCl.

stainless steel planchet with
2-sided tape.
(28) Dry filter under heat lamp for
3-5 minutes.
(29) Measure actinides by alpha
spectrometry.

*Adding 50uL of 30% H2O2 to tube rinse can help improve U decontamination.
Method PerformanceSample
Size (g)100References

242

238

243241

Pu
Pu
Am
Am
TracerMeasuredTracerMeasured
Replicates % Recovery % Bias % Recovery % Bias-3.094 + 4-10386 + 7

100

381 + 15-6.080 + 5-13200200

2382 + 180 + 8

2.0-5.0

93 + 593 + 5-19-181) Sherrod L. Maxwell, “Rapid method for determination of plutonium, americium, and curium in large soil samples,”J. Radioanal. Nucl. Chem., 275(2), 395-402 (2008).
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