Rapid Determination of 89/90Srin Steel Samples$1--
6XPPDU\ RI 0HWKRG   Strontium is separated and measured from 1-2 gram steel samples. Samples are digested
with concentrated nitric, hydrochloric, and hydrofluoric acids. The digestate is evaporated to dryness, the residue
dissolved in HNO3/H3BO3, and a calcium fluoride precipitate is used to concentrate the strontium and remove matrix. An
optional NaOH fusion may also be performed, post sample digestion, to dissolve concrete or stone included in thesample. Strontium is separated from matrix impurities and potentially interfering radionuclides in the sample using
stacked 2 mL and 1 mL cartridges of Eichrom Sr Resin. Radiostrontium is measured on a low background gas flow
proportional counter. Average chemical recovery of strontium, determined by gravimetric yield of stable strontium
carrier, was 90–94%. Measured values of 90Sr agreed to within 3% of reference values for 60 minute count times. The
minimum detectable activity for 90Sr in 2 g samples with 60 minute count times was 0.56 Bq/g. A single operator canprepare batches of 12 samples for the measurement of 90Sr)LJXUH6DPSOH3UHSDUDWLRQ
in less than 8 hours.
Add 1-2 g steel sample to Teflon beaker*.
5HDJHQWV*If using optional fusion, omit HF/H3BO3 and use Zr crucible.
Sr Resin, 2 mL Cartridges (Eichrom SR-R50-S)
Sr Resin, 1 mL Cartridges (Eichrom SR1ML-R50-S)
Add 6 mg Sr Carrier, 5 mL 70% HNO3,Nitric Acid (70%)
20 mL 37% HCl, and 5 mL 49% HF.
Hydrochloric Acid (37%)
Digest on Hotplate to dryness.
Hydrofluoric Acid (49%) or Ammonium Bifluoride
Deionized Water
Add 1 mL 70% HNO3,1.25M Ca(NO3)2
Optional
NaOH
Fusion.
10 mL 37% HCl, and 1 mL 49% HF.
Strontium Carrier (10 mg/mL)
Add
15g
NaOH.
2M Al(NO3)3
Digest on Hotplate to dryness.
Fuse
at600Cfor
20min.
Sr-90 standard
Oxalic acid
Add 5 mL 3M HNO3-0.25M H3BO3
DissolveinDIwater.
Boric acidand 5 mL 37% HCl.
Transferto250mL
c-tube.
3.2M (NH4)2HPO4*
Digest on Hotplate to dryness.
Dilute to 100 mL.
Sodium Hydroxide*
Add 2 mL 1.25M Ca(NO3)2 andAdd 25 mL 1M HCl. Warm to dissolve.
(TXLSPHQW
8.5 mL 3.2 M (NH4)2HPO4.
Transfer to 250 mL centrifuge tube.
Vacuum Pump
Repeat 2 additional times.
Centrifuge
Centrifuge. Decant
Muffle Furnace*supernate. Dissolve ppt. in
Add 2 mL 1.25M Ca(NO3)2.
Hot Plate
80 mL 1.5M HCl.
Dilute to 170 mL with 0.01M HCl.
Analytical Balance
Teflon Beakers (Zr Crucibles*)
Add 25 mL 49% HF. Mix Well. Allow to sit 20 min.
50 mL and 250 mL Centrifuge Tubes
Centrifuge. Discard supernate.
Cupped Stainless Steel Planchets (~5 mL volume)
Gas Flow Proportional Counter
Dissolve precipitate in 5 mL 3M HNO3-0.25M
Vacuum Box (Eichrom AR-24-BOX or AR-12-BOX)
H3BO3, 5 mL 8M HNO3, 5 mL 2M Al(NO3)3. Mix.
Cartridge Reservoir, 20 mL (Eichrom AR-200-RV20)
Warm if necessary. Centrifuge. Check for solids.
Inner Support Tubes-PE (Eichrom AR-1000-TUBE-PE)
Yellow Outer Tips (Eichrom AR-1000-OT)
Continue to Sr Separation.

)LJXUH6WURQWLXP6HSDUDWLRQDQG0HDVXUHPHQW(1) Precondition Sr Resinwith 10 mL 8M HNO3.
(2) Load sample.
(3) Rinse sample tube
with 5 mL 8M HNO3.

2mLSrResin
1mL(4) Add tube rinse to Sr Resin. SrResin(5) Rinse Sr Resin
sequentially with:- 15 mL 8M HNO3
- 10 mL 3M HNO3 - 0.05 oxalic acid- 10 mL 8M HNO3

Gas Flow Proportional Counting*:*(Options for 89/90Sr Discrimination)(8) Evaporate samples to dryness
on tared cupped stainless steel
planchets.
(9) Rinse Sr sample vials with 2 mL
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). 89/90Sr canthen be measured by adding liquid
scintillation cocktail.
(b) Sr fraction from step (10) can be
dissolved in 10 mL 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 15 mL 0.05M HNO3.
(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.

*Additional discussion of 89/90Sr separation and measurement options can be found in Eichrom Application Note
AN-1624-10.

Method Performance for 2 g Steel Samples
Details
90Sr
89Sr+90Sr

SampleReference
replicates (mBq/sample)
10
1.415
83.816

Measured(mBq/sample)
1.41 + 0.04
3.97 + 0.09

Average% Diff.
2.64.1

Sr Carrier% Yield
90.1 + 2.4
94.1 + 2.8

5HIHUHQFHV1) Sherrod L. Maxwell, Brian K. Culligan, Jay B. Hutchison, Robin. C. Utsey, Ralf Sudowe, Daniel R. McAlister, “Rapidmethod to determine 89/90Sr in steel samples,” J. Radioanal. Nucl. Chem., 314(1), 439-450 (2017).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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