AN-1415

Rapid Determination of
210Po in Water Samples

Summary of Method A method for the measurement of 210Po in terrestrial water samples is described, offeringsignificant advantages in detection limit, processing time, and resistance to chemical and radiochemical interferences
over standard methods where polonium is determined following spontaneous deposition onto metal planchets. 210Po isconcentrated from up to 1L samples of ground water or 2L samples of drinking water using a calcium phosphate
precipitate. 210Po is then separated from matrix ions and potentially interfering radionuclides using a 2mL cartridge ofEichrom DGA Resin. 210Po is measured using alpha spectrometry following bismuth phosphate microprecipitation onto
an Eichrom Resolve® Filter. Chemical recoveries of polonium, determined with a 209Po tracer, were typically 80-90%.
210Po measurements typically agreed to reference values to within 3-5%. A single operator can prepare batches of 1224 samples for alpha counting in 3-4 hours. Alpha spectrometry count times will vary depending on desired detection
limit and data quality objectives. Polonium determination may also be integrated into methods for the determination ofactinides (Eichrom Application Note AN-1416).
Reagents
DGA Resin, 2mL Cartridges (Eichrom DN-R50-S)
Nitric Acid (70%)
Hydrochloric Acid (37%)
Ammonium Hydroxide (listed as 28% NH3 or 56% NH4OH)
Hydrogen Peroxide (30%)
Deionized Water
1.25M Ca(NO3)2
3.2M (NH4)2HPO4
209Po tracer
Bi standard solution (1mg/mL)
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 TubesCentrifuge
Alpha Spectrometry System
Analytical Balance
Vacuum Pump
Stainless steel planchets (1.25 inch) with adhesive tape
Heat Lamp

Figure 1. Sample Preparation
1-2L Water Sample.
Add 209Po tracer.
Add 1-2mL of 30% H2O2.
Add 1mL 1.25M Ca(NO3)3 and3mL 3.2M (NH4)2HPO4. Mix Well.
Adjust to pH 9 with 56% NH4OH. Mix.
Allow precipitate to settle.
Decant supernate to <200mL.
Transfer remaining supernate and precipitate
to 250mL centrifuge tubes. Centrifuge
3500rpm for 10 minutes. Decant supernate.
Dissolve precipitate in 10mL 9M HCl.
Transfer to 50mL centrifuge tube.
Rinse 250mL tube with 10mL 2M HCl.
Transfer tube rinse to same 50mL
centrifuge tube.
Load Solution for Po separation.

Figure 2. Polonium Separation on DGA and BiPO4 Microprecipitation(1) Precondition DGA Resin with
5mL 2M HCl.
(2) Load 210Po sample at 1-2mL/min.
(3) Rinse sample tube with 5mL
2M HCl.
(4) Add tube rinse to DGA Resin.
Elute at 1-2mL/min.
(5) Rinse DGA Resin sequentially
with:- 5mL 2M HCl- 15mL 0.25M HCl- 5mL 6M HNO3(10) Wet filter with 3mL 80% ethanol
followed by 3mL DI water.

(6) Dispose of (1) to (5) as waste.

(11) Filter sample.

(7) Strip Po with 15mL 0.05M HNO3
at 1mL/min.

(12) Rinse sample
tube with 5mL
DI water andadd to filter.

(9) Set up Resolve® Filter Funnel
on vacuum box.

(17) Dry filter under heat lamp for
3-5 minutes.
(18) Measure 210Po and 209Po tracer
by alpha spectrometry.

(13) Rinse filter funnel
with 3mL DI water.

2mL DGA
Cartridge
210Po(14) Rinse filter funnel
with 1-2mL 100%ethanol.

Method Performance
VolumeSample
mL
Ground Water
200
Ground Water
200
Ground Water
1000
Drinking Water
2000
6-12 hour count time(15) Draw vacuum until filter is dry.
(16) Remove filter from funnel
assembly and mount filter on
stainless steel planchet withadhesive tape.

(8) To polonium sample:- Add 125ug Bi carrier.
- Add 0.1mL 30% H2O2.
- 0.75mL 3.2M (NH4)2HPO4.
- Mix well.
- Add 200uL 56% NH4OH.
- Mix well. Wait 15-20 minutes.

210% Recovery
Replicates6764209

Po tracer
87.4 + 5.8
82.3 + 3.9
85.0 + 8.2
80.0 + 9.6

Po in Water
210

Po (mBq/L)

Reference
316
1262
63.3
63.3

210

Po (mBq/L)

Measured
308 + 51289 + 6
61.5 + 5.1
61.1 + 6.2% Bias-2.5
2.1-2.8-3.5

References
1) Sherrod L. Maxwell, Brian K. Culligan, Jay B. Hutchinson, Robin C. Utsey, Daniel R. McAlister, “Rapid determinationof 210Po in water samples,” J. Radioanal. Nucl. Chem., 298(3), 1977-1989 (2014).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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