Rapid Determination of 89/90Srin Limestone and Marble

AN-1604-10
Summary of Method Strontium is separated and concentrated from 1.5 gram samples of limestone or marble.
Samples are finely ground and fused in a zirconium crucible for 15 minutes at 600°C with 15 grams of sodiumhydroxide. The fusion cake is dissolved in water, and strontium is concentrated and separated from the matrix using acalcium phosphate precipitate enhanced with iron. A secondary precipitation with calcium fluoride removes additionalmatrix (including silicates) and decreases the volume of precipitate. The calcium fluoride precipitate is dissolved withnitric acid-boric acid-aluminum nitrate to form the load solution. Strontium is separated from remaining matrix andpotentially interfering radionuclides using stacked 2mL + 1mL Sr Resin cartridges. Radiostrontium is measured by gas
flow proportional counting or liquid scintillation counting. Chemical yields of strontium are determined by gravimetricyield or by ICP-AES. Batches of 12-24 samples can be prepared for analysis in less than 8 hours. Simultaneous
separation of actinides can be achieved by using the separation method in AN-1603.
Reagents
Sr Resin, 2mL Cartridges (Eichrom SR-R50-S)
Sr Resin, 1mL Cartridges (Eichrom SR1ML-R50-S)
Strontium Carrier (10mg/mL)
Iron Carrier (50mg/mL Fe, as ferric nitrate)
90Sr standard
HF(49%)
Nitric Acid (70%)
Hydrochloric Acid (37%)
Deionized Water
1.25M Ca(NO3)2
3.2M (NH4)2HPO4
2M Al(NO3)3
Oxalic acid
Boric acid
Sodium Hydroxide

Figure 1. Sample Preparation
1.5g finely ground sample in zirconium crucible
Add 4mg Sr carrier.
Heat samples to dryness on hot plate.
Add 15g of NaOH.
Cover crucibles with zirconium lid and placein muffle furnace at 600°C for 15-20 minutes.
Carefully remove samples from furnaceand cool in fume hood.

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)
50mL and 250mL Centrifuge Tubes
Cupped Stainless Steel Planchets (~5mL volume)
250mL Zirconium crucibles with zirconium lidsCentrifuge
Gas Flow Proportional Counter
Muffle Furnace
Hot Plate/Heat Lamp
Analytical Balance
Vacuum Pump

Add 25-50mL of water and heat on hot
plate to dissolve fusion cake.
Transfer to a 250mL centrifuge tube. Rinsecrucible with water. Dilute to 160mL with water.
Add 50mg Fe Mix.
Add 8.5mL 3.2M (NH4)2HPO4 . Mix.
Centrifuge 10min. Decant supernate.
Dissolve precipitate in 80mL 1.5M HCl. Dilute to 170mL.
Add 15mL 49%HF. Mix. Cool in ice bath 10min.
Centrifuge 10min. Decant supernate.
Dissolve precipitate in 7mL 3M HNO3-0.25M Boric acid,7.5mL 7M HNO3, and 7mL 2M Al(NO3)3. Warm as needed.

Figure 2. Strontium Resin Separation (Optional 90Y Ingrowth)*(1) Precondition Sr Resin with
10mL 8M HNO3.
(2) Load sample at 1-2mL/min.
(3) Rinse sample tube with 5mL
8M HNO3.
(4) Add tube rinse to Sr Resin.
Elute at 1-2mL/min.
(5) Rinse Sr Resin sequentially with:

Gas Flow Proportional Counting:**(8) Evaporate samples to dryness
on tared cupped stainless steel
planchets.
(9) Rinse Sr sample vials with 2mL
0.05M HNO3. Transfer vial rinse toplanchets. Evaporate to dryness.

- 10 mL 8M HNO3
- 10mL 3M HNO3 - 0.05 oxalic acid- 10mL 8M HNO3
(6) Dispose of (1) to (5) as waste.
(7) Strip Sr with 20mL 0.05M HNO3
at 1mL/min.

2mL + 1mL
Sr Resin
Cartridges(10) Weigh planchets on an
analytical balance to determine
gravimetric yield of stable Sr(NO3)2.
(11) Measure radiostrontium insamples on low background gas
flow proportional counter.

**(Options for 89/90Sr Discrimination)(a) Sr fraction from step (7) can betransferred to a liquid scintillation vial.
89Sr can be measured by Cerenkov
counting (no LSC cocktail). 89/90Sr
may then be measured after adding
liquid scintillation cocktail.
(b) Sr fraction from step (10) can be
dissolved in 10mL 8M HNO3 after >7days of 90Y ingrowth. 89/90Sr can beremoved on Sr Resin. 90Y will elute in
Sr Resin load and can be counted byliquid scintillation or gas flow
proportional counting.
(c) Sr fraction from step (10) can be
dissolved in 10mL 8M HNO3 after >7days of 90Y ingrowth. 90Y can beremoved on DGA Resin. 89/90Sr will
elute in DGA Resin load. Additionalrinsing will remove remaining Sr. 90Y
can be eluted in 0.1M HCl andcounted by gas flow proportionalcounting or liquid scintillation(Cerenkov).

*Actinides may also be measured by adding 2mL TEVA, TRU and DGA Resin cartridges above Sr Resin and following
separation scheme in Eichrom Application note AN-1603.
**Additional discussion of 89/90Sr separation and measurement options can be found in Eichrom Application NoteAN-1624-10.
Method PerformanceSample123
AVG% Sr tracer
recovery
84.1
84.8
84.8
84.6 + 0.490

Sr Bq/greference
1.415
1.415
1.41590

Sr Bq/gmeasured
1.41
1.42
1.38
1.40 + 0.02% bias
-0.1
0.4-2.7

References
1) Maxwell, Culligan, Hutchinson, Utsey, Sudowe, McAlister, “Rapid Method to Determine Actinides and Sr-89/90 in
Limestone and Marble Samples,” J. Radioanal. Nucl. Chem. accepted (2016). DOI 10.1007/s10967‐016‐4783‐8
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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