Rapid Determination of Sr inEmergency Air Filter Samples

AN-1434
Summary of Method Strontium is separated and concentrated from air filters. Samples are digested in Teflon
beakers once with HNO3-H2O2-HF and then several times with HNO3-H2O2. After evaporating to dryness from HNO3H3BO3 to complex any residual fluoride, strontium is separated on a 2mL cartridges of Eichrom Sr resin. Radiostrontium
is measured by low background gas flow proportional counting or liquid scintillation counting. Chemical yield ofstrontium, which averaged 86+5%, is determined by gravimetric recovery of stable strontium carrier or ICP-AESmeasurement. 90Sr measurements agreed to within 10% of reference values. 89Sr and 90Sr activities can be determined
by Cerenkov counting or by subsequent 90Y ingrowth, separation and measurement. Sample preparation for batches of
12 samples can be completed by a single operator in <8 hours.
Reagents
Sr Resin, 2mL Cartridges (Eichrom SR-R50-S)
Oxalic acid/Ammonium oxalate
Sr carrier (10mg/mL)
Deionized Water
2M Al(NO3)3
HNO3 (70%)
HF (49%) or NaF
Boric acid
H2O2 (30%)

Figure 1. Sample Preparation
Air Filter + tracers in Teflon beaker.
Wet ash to dryness with 3mL 70% HNO3,
3mL 30% H2O2 and 5mL 49% HF.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.

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)
Hot Plate
Analytical Balance
250mL Teflon beakers
Cupped Stainless Steel Planchets (~5mL volume)Low background gas flow proportional counter
Vacuum Pump

Add 3mL 3M HNO3 –0.25M H3BO3.
Evaporate to dryness.
Dissolve residue in 6mL 6M HNO3
and 6mL 2M Al(NO3)3.
Cool samples to room temperature.
Proceed to Sr Separationand Measurement.

Figure 2. Load Solution Preparation and Strontium Separation(1) Precondition Sr Resin with
5mL 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:

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.

2mLSr Resin
Cartridge(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 addingliquid scintillation cocktail.
(b) Sr fraction from step (10) can bedissolved in 10mL 8M HNO3 after >7days of 90Y ingrowth. 89/90Sr can beremoved on Sr Resin. 90Y will elute inSr Resin load and can be counted byliquid scintillation or gas flow proportional counting.

- 10 mL 8M HNO3
- 5mL 3M HNO3 - 0.05 oxalic acid- 5mL 8M HNO3
(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.
(11) Measure radiostrontium insamples on low background gas
flow proportional counter.

*Actinides also be measured by placing 2mL cartridges of TEVA, TRU and DGA resin above Sr Resin and following theseparation scheme in application note AN-1433.

References
1) Sherrod L. Maxwell, Brian K. Culligan, Gary W. Noyes, “Rapid separation method for actinides in emergency air filter
samples,” Applied Radiation and Isotopes, 68(12), 2125-2131 (2010).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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