AN-1410

Rapid Determination of Sr inEmergency Urine Samples

Summary of Method Strontium is separated and concentrated from 100mL urine samples using calcium
phosphate precipitation. An optional wet-ashing step with HNO3-H2O2 destroys residual organic material. The precipitate
or wet-ashed residue 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 ismeasured on a low background gas flow proportional counter or liquid scintillation counter. Chemical yield of strontium
is determined by gravimetric recovery of stable strontium or ICP-AES measurement. Typical chemical recovery ofstrontium is >80%. Measured values of 90Sr agreed to within 1.7% of reference values for 10 minute count times,
although longer count times can be used to improve detection limits and uncertainty. A single operator can complete theseparation 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)
Hydrogen Peroxide (30%)
Deionized Water
1.25M Ca(NO3)23.2M (NH4)2HPO4
Sr Carrier (10mg/mL)
2M Al(NO3)390Sr standard
Oxalic acid

Figure 1. Sample Preparation
100 mL urine+4mg Stable Sr Carrier+2mL 1.25M Ca(NO3)3+5mL 3.2 M (NH4)2HPO4Mix WellAdjust to pH 10 with NH4OH
Mix WellCentrifuge 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
Centrifuge
Cupped Stainless Steel Planchets (~5mL volume)
Gas Flow Proportional Counter
Hot Plate
Analytical Balance
250mL Glass Beakers
Vacuum Pump

Dissolve precipitate in 10mL
70% HNO3 + 5mL 30% H2O2.
Wet ash in 250mL glass beaker.
(adds 30-45 minutes)

Dissolve 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:**(Options for 89/90Sr Descrimination)(8) Evaporate samples to dryness
on tared cupped stainless steel
planchets.

(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.

(9) Rinse Sr sample vials with 2mL
0.05M HNO3. Transfer vial rinse toplanchets. Evaporate to dryness.

(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.

(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-1412, “Rapid Determination of Actinides in Emergency Urine
Samples.”

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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