AN-1428

Rapid Determination ofActinides in Fecal Samples

Summary of Method Actinides are separated andmeasured from fecal samples. Fecal samples aremuffled and wet ashed prior to fusion with sodiumhydroxide. Sequential precipitation steps remove
sample matrix prior to actinide separation on 2mL
cartridges of Eichrom TEVA, TRU and DGA resins.
Actinides are measured by alpha spectrometry
following cerium fluoride microprecipitation onto
Eichrom Resolve® Filters. Samples can be prepared formeasurement in less than 24 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 iron nitrate)
242Pu (or 236Pu if meas. Np), 243Am and 232U tracers
Oxalic acid/Ammonium oxalate
La carrier (10mg/mL)
Ce carrier (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 ethanol
Sulfamic AcidAscorbic 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 Ceramic crucibles
Hot Plate
250mL Zirconium crucibles with zirconium lids
Stainless Steel Planchets with adhesive tape
Alpha Spectrometry System
Vellum paper
Centrifuge
Muffle Furnace
Analytical Balance
1L Glass Beakers
Vacuum Pump
Heat Lamp

Figure 1. Sample Preparation
Fecal sample + tracers in 1L glass
beaker lined with vellum paper.
Muffle at 250°C ~20 min. to dry. Muffle at 350°C for 20 min.
Muffle 450°C for 20 min. Muffle 550°C for 45 min.
Transfer char to 250mL
ceramic crucible. Muffle at850°C for 1.5 hours. Transfer
solids to 250mL Zr crucible.
Rinse ceramic crucible with
70% HNO3. Add to Zr crucible.

Wet ash material remaining
in beaker with 5mL 70%
HNO3 and 5mL 30% H2O2.
Heat to dryness. Transfer
residue to Zr Crucible with
70% HNO3.

Heat Zr crucibles to dryness on hotplate.
Muffle at 600°C until solids turn white/lavender.
Fuse samples with 20g NaOH at 600°C for 15 minutes.
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. Cool to room temp.
Add 125mg Fe and 6mg La to c-tube. Dilute to 180mL.
Add 1mL 1.25M Ca(NO3)2, 2mL 3.2M (NH4)2HPO4,6mL 10% TiCl3. Mix. Cool in ice bath for 10min.
Centrifuge at 3500rpm. Decant Supernate.
Partially dissolve precipitate in 120mL 1.5M HCl.
Some solids will remain. Dilute to 170mL.
Add 1mg La, 1mL 1.25M Ca(NO3)3, and5mL 10% TiCl3. Mix. Add 22mL 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, 40uL 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 2mL
TEVA, TRU, DGA cartridges
TEVAwith 10mL 3M HNO3.
(2) Load sample solution.
(3) Rinse sample tube
with 5mL 3M HNO3. Add
TRU
tube rinse to cartridges.
(4) Rinse cartridges with
10mL 3M HNO3.*DGA(5) Separate TEVA, TRU,and DGA cartridges.
(6) Rinse TEVA cartridge with:-10mL 3M HNO3
-20mL 9M HCl (Remove Th)-5mL 3M HNO3
(7) Strip Pu (and Np) from TEVAcartridge with 20mL 0.1M HCl0.05MHF-0.01M TiCl3 .
(8) Add 0.5mL 30% H2O2 for Uranium
decon. in alpha source preparation.
(9) Rinse DGA cartridge with 10mL
0.1M HNO3. (U removal).
(10) Place TRU cartridge above DGA.

(12) Separate TRU cartridge from DGA (23)Rinse filter
cartridge. Set TRU aside for U recovery.
funnel with 3mL
DI water and(13) Rinse DGA cartridge with:
2mL 100%-5mL 3M HClethanol.
-3mL 1M HNO3(24) Draw vacuum-15mL 0.05M HNO3
until filter is dry.
(14) Strip Am and Cm from DGA with
10mL 0.25M HCl. Add 0.2mL 30% H2O2.
(15) Rinse TRU cartridge with:-15mL 4M HCl-0.2M HF-2mM TiCl3-5mL 8M HNO3.

(25) Remove filter fromfunnel assembly andmount filter on stainlesssteel planchet with 2-sided tape.

(16) Strip U from TRU with 15mL of
0.1M ammonium bioxalate.
(17) Add 0.5mL 10% TiCl3 to U samples.

(18) Add 50-100ug Ce carrier to allsamples. Mix well. Add 1mL 49% HF.
Mix well. Wait 15-20 minutes.
(19) Set up Resolve® Filter Funnel onvacuum box.
(20) Wet filter with 3mL 80% ethanol
followed by 3mL DI water.
(21) Filter sample.
(11) Strip Am/Cm from TRU onto DGA (22) Rinse sample tube with 5mL DI
with 15mL 3M HCl at 1-2mL/min.
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 can improve Uranium recoveries and decontamination in Pu(Np) fractions.
Method Performance
Analyte239/240

Pu

238

Samples5242

Pu% Tracer
Recovery95 + 9Pu

95 + 90.066 - 0.156

0.071 - 0.146-5.3 to 3.0

Am

83 + 40.199 - 0.476

0.201 - 0.464-11 to 1.0

Tracer

Reference(Bq/sample)
0.085 - 0.204

Measurement(Bq/sample)
0.081 - 0.198% Bias-11 to -1.5

Pu

5242

Am

5243

5232

U

63 + 70.226 - 0.541

0.196 - 0.592-9.0 to 2.9

5U
6 hour count time

232

U

63 + 70.218 - 0.521

0.206 - 0.536-13 to 9.4

241238

U234

References1) Sherrod L. Maxwell, Brian K. Culligan, Jay B. Hutchinson, Ronie B. Spencer “Rapid fusion method for determinationof actinides in fecal samples,” J. Radioanal. Nucl. Chem., 298(3), 1533-1542 (2013).
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