$1--

Rapid Determination of 226Rain Steel Samples

6XPPDU\ RI 0HWKRG  226Ra is isolated from 1 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 andcalcium fluoride precipitate is used to concentrate the radium and remove matrix. Radium is separated from matrix
impurities and potentially interfering radionuclides in the sample using cation exchange and DGA Resin. Radium ismeasured by alpha spectrometry following barium sulfate microprecipitation onto Eichrom Resolve Filters. The chemicalrecovery, determined by 133Ba tracer, was 89–95%. Measured values of 226Ra agreed to within 5% of reference values
for 16 hour count times. The minimum detectable activity for 226Ra in 1 g samples with 16 hour count times was
0.5 mBq/g. A single operator can prepare batches of 12 samples for the measurement of 226Ra in less than 8 hours.
5HDJHQWVCation Exchange Resin (Eichrom C8-B500-F-H)
DGA Resin, Normal 2 mL Cartridges (Eichrom DN-R50-S)
Ammonium Hydroxide (Listed as 28% NH3 or 56% NH4OH)
Nitric Acid (70%)
Deionized Water
133Ba Tracer
1.25M Ca(NO3)2
Barium Carrier (1 mg/mL)
Isopropyl Alcohol
Ammonium Sulfate
Denatured Ethanol
Hydrochloric Acid (37%)
Hydrogen Peroxide (30%)(TXLSPHQW
Plastic Chromatography Column (Eichrom AC-50E-5M)
Column Extension Funnel (Eichrom AC-20X-20M)
Vacuum Box (Eichrom AR-24-BOX or AR-12-BOX)
Cartridge Reservoir, 20 mL (Eichrom AR-200-RV20)
Inner Support Tubes-PE (Eichrom AR-1000-TUBE-PE)
Yellow Outer Tips (Eichrom AR-1000-OT)
Resolve Filter in Disposable Funnel (Eichrom RF-DF-25-25PP01)
50 mL Centrifuge Tubes
Centrifuge
Hotplate
150 mL Glass beakers
Vacuum Pump
Heat Lamp
Stainless Steel Planchets with adhesive tape
Alpha Spectrometry System
Gamma Spectrometry System (133Ba tracer))LJXUH6DPSOH3UHSDUDWLRQ
Add 1 g steel sample to Teflon beaker.
Add 133Ba tracer, 5 mL 70% HNO3,
20 mL 37% HCl, and 5 mL 49% HF.
Digest on Hotplate to dryness.
Add 5 mL 70% HNO3,
10 mL 37% HCl, and 1 mL 49% HF.
Digest on Hotplate to dryness.
Add 5 mL 3M HNO3-0.25M H3BO3
and 5 mL 37% HCl.
Digest on Hotplate to dryness.
Add 10 mL 0.25M HCl. Warm to dissolve.
Transfer to 50 mL centrifuge tube.
Repeat 2 additional times.
Add 2 mL 1.25M Ca(NO3)2 and 6 mL 49% HF.
Mix Well. Allow to sit 20 min.
Centrifuge. Discard supernate.
Dissolve precipitate in 10 mL 1M HCl-0.25M H3BO3 and 10 mL 1M HCl.
Mix. Warm if necessary. Centrifuge.
Check for solids.
Continue to Ra Separation.

)LJXUH&ROXPQ3XULILFDWLRQDQG$OSKD6RXUFH3UHSDUDWLRQ(8) Add 50 ug Ba carrier. Mix well.

(1) Prewash 5.0 g 50Wx8
200-400 mesh, cation exchange resin column:-10 mL deionized water-20 mL 6M HCl-10 mL 0.5M HCl(2) Load Sample.

(9) Add 3 g (NH4)2SO4 and 5mL
isopropanol. Mix well.
(10) Place in ice bath for 30 minutes.
(11) Set up Resolve® Filter Funnel
on vacuum box.

(3) Rinse 30 mL 3M HCl.
(4) Add 2 mL DGA cartridge below
cation exchange column.
(5) Strip Ra/Ba with 35 mL 5M HNO3.
(6) Add 3 mL 30% H2O2.
Evaporate to dryness.
(7) Dissolve residue in 10 mL
1.5M HCl. Transfer to 50
mL c-tube with 2 x 7 mL
1.5M HClϮϮϲ(18) Remove filter from funnel
assembly and mount filter on
stainless steel planchet withadhesive tape.

ZĂ'(12) Wet filter with 3 mL 80% ethanol
followed by 3 mL DI water.

(13) Filter sample.
(14) Rinse sample
tube with 5 mL
DI water andadd to filter.

(19) Dry filter under heat lamp for
3-5 minutes.
(20) Measure 226Ra by alpha
spectrometry and 133Ba bygamma spectrometry.

(15) Rinse filter funnel
with 3 mL DI water.
(16) Rinse filter funnel
with 1-2 mL
100% ethanol.
(17) Draw vacuum until filter is dry.

Method Performance for 1 gram Steel Samples
SampleReference
replicates (mBq/sample)
536.8
573.7
5184

Measured(mBq/sample)
36.5 + 0.8
74.9 + 3.1
183 + 5

Average% Diff.
1.9
3.7
1.9

133Ba tracer% Yield
95.4 + 5.9
88.8 + 1.8
90 + 13

5HIHUHQFHV1) Sherrod L. Maxwell, Brian K. Culligan, Robin C. Utsey and Daniel R. McAlister, “Rapid Method to Determine 226Ra in
Steel Samples,” J. Radioanal. Nucl. Chem., 314(2), 1417-1423 (2017).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

www.eichrom.com