Chromatographic Separation and Measurement of Charged-Particle Emitting

Radionuclides

Timothy A. DeVol, Ph.D., C.H.P.

Environmental Engineering and Science

Clemson University

16 May 2000

Introduction to Dual Functionality Materials

• Liquid Extractive Scintillators– Ludwick, Health Physics, 1961, 6, 63-65.– McDowell and McDowell, Liquid Scintillation Alpha Spectrometry, CRC

Press, Boca Raton, 1994.

• Scintillating Cation and Anion Ion Exchange Resin– Heimbuch, et al., Radioisotope Sample Measurement Techniques in Medicine

and Biology, Proceedings of the International Atomic Energy Agency Symposium, Vienna, May 24-28, 1965.

• Solid Extractive Scintillators for 90Sr and 99Tc– Egorov et al., Anal. Chem 71 (1999) 5420-5429

• Solid Extractive Scintillators for 90Sr, 99Tc and Actinides – DeVol et al., Radioactivity&Radiochemistry Vol. 11 #1 (2000)

Separation and Detection Schemes

• Single scintillation crystal, e.g. CaF2:Eu, anthracene

• Extractant coated onto inert scintillator

• Mixture of extraction resin with granular scintillator

• Extractant impregnated into a scintillating chromatographic resin (ScintEx)

Solid Extractive Scintillators

• Sequential Extraction Chromatography and Flow-cell Detection

Off-line quantification

• Simultaneous Extraction Chromatography and Flow-cell Detection

On-line quantification

Materials and Methods

• Mixed-ResinMixture of:– 100 - 150 m TEVA Resin or Sr Resin

– 100 - 200 m BC-400 Plastic Scintillation Beads (Bicron)or 63 - 90 m GS-20 Scintillating Glass (Applied Scintillation Technology)

Extractive Scintillator Resin

• ScintEx resin (Patent Pending)– Inert polystyrene chromatographic resin (Amberchrom CG-

161c) impregnated with PPO and DM-POPOP using a modification of the Ross 1991 procedure

– Scintillating chromatographic bead impregnated with extractant (Eichrom proprietary technology)

• Extractant for Sr• ABEC-2000• Quaternary Amine, Aliquat-336 (TEVA)

• CMPO extractant in TBP for actinides

Off-Line Evaluation Procedures

• Resin dry packed into 9 mm x 50 mm opaque column

• Conditioning, loading and wash performed with standard Eichrom procedures

• Column placed in 7-mL HDPE vial WITHOUT introduction of LSC cocktail

• Activity quantified with Hidex Triathler liquid scintillator counter

Hidex Triathler

Results and Discussion

• Mini-Column Experiments (Off-Line)– Compare pulse-height spectra (luminosity) and

detection efficiency

• Flow-Cell Experiments (On-Line)– Loading and elution profiles (loading and

detection efficiency, and total recovery)– Regeneration capability

89Sr Pulse-Height Spectra from Triathler

0.1

1

10

10 100 1000

Channel Number

Net Count Rate (cps)

Sr ScintEx O; 50.8%Sr GS20M; 50.3%Sr BC400M; 81%SrGS20; 14.4%Sr ScintEx; 9.1%

Triathler Pulse-Height Spectra for 89Sr and 90Sr on Sr ScintEx O

0.1

1

10

10 100 1000

Channel Number

Net Count Rate (cps)

Sr-89, 50.8%Sr90/Y90, 36.0%Sr-90, 14.4%

Schematic of On-Line Flow-Cell Detection System

Computer

Effluent

Sam

ple

Loa

ding

Solu

tion

Elu

ant

LSC

Radiation Detector

PMT PMT

Flow-cell

Manually controlled pump

Flow-Cell Radiation Detection System

IN/US -Ram Model 1

Extractive Scintillator Flow-Cell

Extractive scintillator flow-cellwas constructed of with <0.5 gof resin packed into 1.5 mm IDx 140 mm polytetrafluoro-ethylene tubing to yield an approximate pore volume of 200-400 L. The tubing is coiled to an approximate diameter of 2.54 cm and placed between the photomultiplier tubes of the radiation detector.

Loading and Elution of 99Tc(VII)TEVA/BC-400 Mixed Resin

10-1

100

101

0

0.2

0.4

0.6

0.8

1

0 500 1000 1500 2000 2500 3000 3500 4000

99Tc in 2-M HCl

2-M HCl

8-M HCl

Count Rate (cps)

Flow Rate (mL min

-1)

Time (s)

99Tc) = 7.5%

Loading and Elution of 99TcTEVA/BC-400 Mixed-Resin Flow-Cell

137Cs Interference Test

10-1

100

101

102

103

0 1000 2000 3000 4000 5000 6000

Count Rate (cps)

Time (s)

99Tc in 2 M HCl

2 M HCl

8 M HNO3

137Cs in 2 M HCl

99Tc; 5 mL; 24 Bq mL-1

137Cs; 1 mL; 7.2 kBq mL-1

Loading and Elution of 99TcABEC ScintEx Flow-Cell

0

200

400

600

800

1000

1200

0 500 1000 1500 2000 2500 3000 3500 4000

Counts per 10 s

Time (s)

Loading Efficiency ~ 100%Total Tc Recovery ~ 99.5%Detection Efficiency ~ 79%

99Tc in 4M NaOH

4 M NaOH

DDI H2O

Loading and Elution of 99TcTEVA ScintEx Flow-Cell

0

200

400

600

800

1000

0 1000 2000 3000 4000

Counts per 10 s

Time (s)

Loading Efficiency = 99.9%Total Tc Recovery = 99.4%Detection Efficiency = 51%

99Tc in 0.1 M HNO3

0.1 M HNO3

8 M HNO3

Loading and Regeneration of TEVA ScintEx

0

20

40

60

80

100

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11

Detection Efficiency - 0.1 M HNO3

Detection Efficiency - 2 M HNO3

Loading Efficiency

Total Recovery

Detection Efficiency (%)

Loading Efficiency or Total Recovery (%)

Trial #

89Sr Loading and Elution Profile on Sr ScintEx O

(89Sr) = 65.4%

Loading 90Sr/90Y on Sr ScintEx P

0

2

4

6

8

10

12

14

16

18

0 500 1000 1500 2000 2500 3000

Time (s)

Count Rate (cps)

Sr/Y-90, 92.5 Bq

Y-90, 160 Bq

Sr)= 40%

102

Multiple Loading and Elution of 89Sr on Sr ScintEx O

0

20

40

60

80

100

120

0 5000 10000 15000

Time (s)

Count Rate (cps)

Avg. Detection efficiency 60 4%

Avg. Loading efficiency 101 ± 1%

65.4%58.8% 57.6% 59.6%

TRU ScintEx ResinPulse Height Spectrum

Sequential Elution of 241Am, 239Pu and 233U from TRU ScintEx Resin

Off-Line Counting

On-Line Counting

Sample Load in 2-M HNO3

4-M HCl

4-M HCl + 0.02-M TiCl32-M HCl0.1-M Ammonium Bioxalate

Conclusions

• Extractive scintillator media can be realized a number of ways• Extractive scintillator media can be selective to analyte of interest

– demonstrated with technetium-selective, strontium-selective and actinide-selective extractant

• Loading, retention, and elution similar to non-scintillating resin• Quantification has been demonstrated on-line and off-line• Limited spectroscopy appears to be available with the actinide-

selective ScintEx resin• Absolute detection efficiency ranges from ~40% for 90Sr to near

100% for actinide- selective ScintEx resin

Acknowledgments

• James Harvey, Eichrom IndustriesJonathan Duffey, formerly from Eichrom

• From Clemson University:Robert Fjeld, Alena Paulenova (on leave from Comenius´ University, Slovak Republic), James Roane

• John Leyba, WSRTC• NSF SBIR Phase I contract # NSF/SBIR-9760934• South Carolina University Education and Research Foundation

TOA #KC86372-O.• DOE Environmental Management and Science Program, Project

#70179