1. The Determination of 226Ra in Water Samples
Anil H. Thakkar & Michael Fern
Eichrom Technologies, Inc.
David McCurdy
Duke Engineering & Services
Basically this piece of work was carried for our potential client Quanterra, formerly known as IT Corp.
A protocol was proposed to Quanterra based on their needs to carry out day to day analyses in their lab.

2. Objectives To design a procedure for radium in water which would:
be a simple, short and quick procedure
allow to measure Ra-226 and Ra-224 via alpha spectroscopy and Ra-228 via Ac-228 measurements
eliminate the tedious steps of precipitation and metathesis
An improved procedure was developed to separate Am,Pu and U in variety of water matrices.

3. Current Procedure Used
Barium sulfate precipitation
Conversion to BaCO3- tedious and time consuming

4. Current Procedure Used
Sample + Ba carrier + Ba Conc.H2SO4_+ Heat BaSO4
Precipitate allowed to settle for several hours or overnight
Precipitate collected and converted to BaCO3

5. New Approach Water samples Cation exchange resin column
Eichrom Ln Resin column

6. Preparation of Water Samples
0.5 L / 1.0 L water samples
Acidified to pH 2
Add 133Ba as a tracer

7. Eichrom Cation Exchange Column
Load solution: 0.5 L/ 1.0 L of sample
Rinse with 50 mL of 0.1M HNO3
Strip Ra and Ba with 100 mL of 8M HNO3

8. Preparation of Load Solution for Ln Resin Column
Evaporate eluent from cation exchange column to dryness
Dissolve residue in 10 ml of 0.095M HNO3 acid
Load on Eichrom Ln Resin column

9. Ln Resin Column Separation
(1) Load: 10 mL of 0.095M HNO3,
Collect (1) and (2) for Ba & 226Ra
(2) Rinse: 15 mL of 0.095M HNO3
On Uteva spec, the actinides were loaded with a load solution of 3M HNO3/0.5 M Al(NO3)3 solution, Pu was reduce by Iron.
Am/Pu pass thru, Uteva, therefore the load solution and rinse are collected, Uranium is stripped by 0.01 M HCl .
(3) Strip: 10 mL of 0.35M HNO3
collect (3) for 228Ac

10. 226Ra Via Alpha Spectrometry
Evaporate 226Ra/133Ba fraction to 10 mL volume
Add 0.1 ml of 0.75 mg/ml barium carrier
Add 3 mL of 40% sodium sulfate, 4 drops of 1:1 acetic acid. Swirl
Add 0.2 mL of seeding suspension. Mix
Place tubes in cold water bath for 30 minutes
Filter on 0.1 micron filters, count via alpha spectrometry

11. eichrom 133Ba Via Gamma Counter
Count 133Ba tracer yield via gamma spectrometry

12. 228Ac Via Gas-Flow Proportional Counter
Add 50 micrograms of cerium carrier
Add 1.0 mL of HF
Filter on 0.1 micron filters
Measure for beta radiation

13. 226Ra % Recoveries-0.5L DI Water

14. 226Ra Alpha Spectrum

15. 133Ba Gamma Spectrum

16. 226Ra, 224Ra, and Daughters
224Ra
226 Ra
220Rn
218Po
222Rn

17. 226Ra % Recoveries in Tap water

18. 226Ra in EPA Sample Sept.18, 1998

19. 226Ra in NJ Sample

20. 226Ra in Georgia Inst. Of Tech. Sample# S8933

21. 226Ra in Georgia Inst. Of Tech. Sample# WS 14776

22. Ca and Mg Interference
50, 100, 200, 400 and 500 ppm of Ca and Mg solutions were tested
500 mL and 100 mL volumes tested

23. Ca and Mg Interference in 500 mL Samples

24. Ca Interference in 100 mL of Sample

25. Detection Limits

26. Summary <1.0 pCi/L detection limits achievable
A good replacement for BaSO4 precipitation
Eliminates inconsistent metathesis steps
Reduces usage of chemicals/reagents
Provides consistency and saves time
High amounts of Ca and Mg interferences handled well with 100 mL samples
Acceptable 226Ra recoveries

27. Acknowledgements
Special thanks to
Dr. B. Parsa, New Jersey department of health, NJ
Dr. B. Kahn, Georgia Institute of Technology, GA