Cesium 134/7 determination in aqueous samples – Version 1.0 –18/09/15 - TKI

Summary
1Scope ..................................................................................................................................................... 22

Summary of Method ............................................................................................................................. 2

3

Significance of Use ................................................................................................................................ 2

4Interferences ......................................................................................................................................... 2

5Apparatus .............................................................................................................................................. 3

6Reagents................................................................................................................................................ 3

7Procedure .............................................................................................................................................. 4

8REFERENCES .......................................................................................................................................... 6

1 Scope
This procedure describes a method for the concentration and measurement of Cs-134/7 inaqueous samples (surface, ground and sea water samples).

2 Summary of Method
Cesium is concentrated and separated using AMP-PAN or KNiFC-PAN Resin prior to gamma
spectrometry counting. AMP-PAN or KNiFC-PAN Resin are used to concentrate cesium fromup to 100L aqueous samples. Flow rates up to 300 mL/min may be employed(1)(2).
AMP-PAN may be used for neutral and acidic samples (up to 1M HNO3), KNIFC-PAN for
neutral and slightly alkaline samples(2)(3)(4).
Stable cesium can be used to monitor method yields and correct results to improve precision andaccuracy(1)(2). Ideally the Cs content should be determined by ICP-MS, however atomic
absorption or emission techniques may also be used, the amount of Cs carrier added will need tobe adjusted accordingly.
For 100L samples and 50-70h counting the following MDAs were reported(2): 0.18 Bq.m-3 forCs-134, 0.15 Bq.m-3 for Cs-137.

3 Significance of Use
This method is a rapid and reliable method for measurement of Cs-134/7 in aqueous samples.

4 Interferences
Large amounts of Na and K will not interfere with Cs uptake as long as the Cs content of the sample
is small compared to the Cs capacity of the resin ( 64 mg Cs/g wet resin for AMP-PAN(1) and 256
mg Cs/g dry KNiFC-PAN resin(3) – or 69 mg Cs/mL wet KNiFC-PAN resin (3)).

25 Apparatus
5.1

Column or cartridge with appropriate holder or rack

5.2

Suitable reservoir or pump system

5.3

Gamma pulse height analyzer

5.4

Petri dishes

5.5Beakers

5.6

IR lamp

6 Reagents
6.1

Deionized water.

6.2

Ethanol (EtOH)

6.3

Nitric acid (15.7 M)- concentrated HNO3 (sp gr 1.42)

6.4

Nitric acid (0.1M) -Add 6.4 mL of concentrated HNO3 to 900 mL of water and dilute to 1
liter with water.

6.5

Optional: Cesium (Cs) carrier (1 mg/mL), - Dissolve 126,7 mg of CsCl in50 mL waterand dilute to 100mL with water

6.6

Optional: Sodium Hydroxyde (5M) – dissolve 199.95 g NaOH pellets in 600 mL of waterand dilute to 1 liter with water.

6.7

Optional: Ammonium Hydroxyde (5M) – dissolve 175 g NH4OH in 600 mL of water anddilute to 1 liter with water.

6.8

AMP-PAN or KNiFC-PAN Resin: M grade, bulk resin or pre-packed columns

37 Procedure
7.1

Synopsis

Sample preparation

Cs concentration onAMP-PAN or KNiFC-PAN
optional

Gamma spectrometryYield determination via
ICP-MS

7.2 Cesium separation using AMP-PAN or KNiFC-PAN:
7.2.1 Measure the sample volume using a suitable mean, sample volumes up to 100 L may beanalyzed(2).
7.2.2 If necessary filter the sample
7.2.3 Acidify the sample using concentrated nitric acid (6 mL conc. HNO3 per L of sample).
Note: Alternatively the sample can be loaded without acidification when using KNiFC-PAN

7.2.4 Optional: Add 1 ml of 1 mg/ml cesium carrier (for yield determination via ICP-MS) into
each sample aliquot. The amount of Cs added may need to be adjusted in function ofsample volume and sensitivity of the ICP-MS
7.2.5 Homogenize sample
7.2.6 Optional: Withdraw suitable aliquot for ICP-MS determination of initial Cs content, thesize of the aliquot will depend on Cs content and sample volume. For 100 L samples and
1 mg Cs typically a volume of 5 mL is withdrawn.
7.2.7 Place columns or cartridges on rack or into suitable pumping system. Attach suitablereservoirs or tubing.
7.2.8 Ensure that a container is below each column/cartridge.
47.2.9 Add at least 10 ml of 0.1 M HNO3 to each column/cartridge to condition columns, allow
to soak
7.2.10 Slurry an appropriate amount of AMP-PAN or KNiFC-PAN in 0.1M HNO3. The exact
amount of resin will depend on the sample size, typically a resin bed of 5 mL is used for
20 L samples, 25 mL for 100 L samples (rule of thumb: 1 mL resin per 4L of sample)
Note: The resins have the following densities: AMP-PAN: 0.27 g dry resin.mL-1; ~1g wet resin.mL-1; KNiFCPAN: 0.20 g dry resin.mL-1; ~1g wet resin.mL-1

7.2.11 Transfer slurry into column and allow to settle. Adjust amount of resin added to thecolumns to obtain desired bed volume.
7.2.12 Allow supernatant to drain.
7.2.13 Adjust flow rate to ≤ 300 mL/min (the optimum flow rate is in the order of 35 – 40mL/min).
7.2.14 Place fresh sample container below the columns/cartridges
7.2.15 Load each sample onto the appropriate columns/cartridges and allow to drain.
7.2.16 Optional: Homogenize collected sample feed solution and withdraw suitably sized aliquot
for yield determination (see 7.2.6)
7.2.17 Rinse columns/cartridges with two times 10 ml of 0.1 M HNO3 (AMP-PAN) or deionizedwater (KNiFC-PAN). Allow to drain
7.2.18 Remove tubing/reservoir
7.2.19 Transfer resin into suitable beaker using EtOH rinses
Note: Alternatively Cs might be eluted from the column using 5M NH 4Cl or 5M NaOH. For AMP-PAN e.g.
10 bed volumes elute ~90% of the sorbed Cesium, 10 bed volumes of 5M NaOH will remove a slightly higheramount(5)7.2.20 Carefully agitate resin/EtOH (e.g. using an orbital shaker) to homogenize the resin
7.2.21 Dry resin under IR lamp
7.2.22 Transfer dried resin into suitable Petri dish assuring a homogeneous thickness of the resinlayer.
7.2.23 Count sample on gamma spectrometer, adjust counting time in function of detection limit
to be obtained.
Note: Calibration sources are prepared using identical amounts of resin homogeneously spiked with a
traceable Cs-137 standard solution.

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8 REFERENCES(1) Pike et al., Extraction of Cesium from Seawater off Japan using AMP-PAN Resin andQuantification via Gamma Spectrometry and Inductively Coulped Mass Spectrometry, J.
Radioanal. Nucl. Chem, DOI 10.1007/s10967-012-2014-5, 2012
(2) Kamenik J. et al., Fast Concentration of Dissolved forms of Cesium Radioisotopes fromLarge Seawater Samples, J. Radioanal. Nucl. Chem, DOI 10.1007/s10967-012-207-4, 2012
(3) Kamenik J., Comparison of Some Commercial and Laboratory Prepared Caesium IonExchangers, Czechoslovak Journal of Physics, Vol.53 (2003), Suppl.A, A571-A576(4) Brewer K.N. et al., AMP-PAN column Tests for the Removal of 137Cs from Actual andSimulated INEEL High-Activity Wastes, Czechoslovak Journal of Physics, Vol. 49 (1999),Suppl. S1, 959-964(5) Sebesta F, Stefula V (1990) Composite ion exchanger with ammonium molybdophosphate
and its properties. J Radioanal Nucl Chem Art 140(1):15–21

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