AN-1411

Rapid Determination of Sr in
Emergency Water Samples

Summary of Method Strontium is separated and concentrated from up to 400mL water samples using calcium
phosphate precipitation. The precipitate is dissolved in nitric acid and aluminum nitrate. Strontium is then separated
from matrix impurities and potentially interfering radionuclides in the sample using a 2mL cartridge of Eichrom Sr Resin.
Radiostrontium is measured on a low background gas flow proportional counter or liquid scintillation counter. Chemicalyield of strontium is determined by gravimetric recovery of stable strontium or ICP-AES measurement. Typical chemical
recovery of strontium is >80%. Measured values of 90Sr agreed to within 14% of reference values for 10 minute counttimes, although longer count times can be used to improve detection limits and uncertainty. A single operator can complete the separation method for batches of 12-24 samples in as little as 3-4 hours.

Reagents
Sr Resin, 2mL Cartridges (Eichrom SR-R50-S)
Nitric Acid (70%)
Ammonium Hydroxide (listed as 28% NH3 or 56% NH4OH)
Deionized Water
1.25M Ca(NO3)23.2M (NH4)2HPO4Strontium Carrier (10mg/mL)
2M Al(NO3)390Sr standard
Oxalic acid

Figure 1. Sample Preparation
400mL water+4mg Stable Sr Carrier*+2mL 1.25M Ca(NO3)3+5mL 3.2 M (NH4)2HPO4.
Mix Well.
Adjust to pH 10 with NH4OH.
Mix Well.

Centrifuge 3500 rpm, 10 min.
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
CentrifugeCupped Stainless Steel Planchets (~5mL volume)
Gas Flow Proportional Counter
Analytical Balance
Vacuum Pump

*Amount of Sr
carrier may needto be adjusted toaccount for nativeSr content insample.

Dissolve precipitate/residue in 8mL
6M HNO3 and 8mL 2M Al(NO3)3.

Load Solution to Sr
Resin Separation.

DecantSupernate
To WasteFigure 2. Load Solution Preparation and Strontium Separation(1) Precondition Sr Resin with
10mL 8M HNO3.
(2) Load sample at 1-2mL/min.
(3) Rinse sample tube with 3mL
3M HNO3.
(4) Add tube rinse to Sr Resin.
Elute at 1-2mL/min.
(5) Rinse Sr Resin sequentially with:- 10 mL 8M HNO3
- 5mL 3M HNO3 - 0.05 oxalic acid- 5mL 8M HNO3

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

(a) Sr fraction from step (7) can betransferred to a liquid scintillation vial.
89Sr can be measured by Cerenkov
counting (no LSC cocktail). 89/90Srmay 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.

(6) Dispose of (1) to (5) as waste.
(7) Strip Sr with 15mL
0.05M HNO3 at
1mL/min.

*(Options for 89/90Sr Descrimination)(10) Weigh planchets on an
analytical balance to determine
gravimetric yield of stable Sr(NO3)2.

2mL + 1mL
Sr ResinCartridges(11) Measure radiostrontium insamples on low background gas
flow proportional counter.

Actinides may also be measured by adding a 2mL TEVA, TRU and DGA cartridges above Sr Resin and following theseparation scheme in Eichrom application note AN-1413, “Rapid Determination of Actinides in Emergency WaterSamples.”References
1) Sherrod L. Maxwell, Brian K. Culligan, “Rapid separation method for emergency water and urine samples,” J.
Radioanal. Nucl. Chem., 279(3), 901-907 (2009).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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