Rapid Separation Methods for Bioassay
Samples
S. L. Maxwell, III and D. J. Fauth
Westinghouse Savannah River Site
Advances in Rapid Column Extraction
• Significant advances in last 5 to 10 years
• Broad application in wide range of labs
– Advancing analytical technology in process lab, bioassay lab,
environmental lab, etc.
• Sample preparation required for wide range of analytical work
– Remove matrix interferences prior to assay
– Preconcentrate analyte
• Advantages
– simpler, more selective than ion exchange
– vacuum box speed improvements with cartridge technology
– less waste, lower acidity, less hazardous
Improvements In Column Extraction
• 1990’s: Need to upgrade radiochemistry methods at SRS
– Replace solvent extraction methods in CLAB-mixed waste
– Upgrade analytical methods in SRS Bioassay Lab
• Rapid Separation Methods
– Process laboratory (liquid and solid samples)
– Bioassay laboratory (urine, fecal)
– Environmental laboratory (soil)
Improvements In Column Extraction
• Rapid Column Extraction Applications at SRS
– Process and waste analyses
• Pu, Np, U, Am, Th, Sr, Tc-99 for waste and process solutions at SRS
(tandem methods)
– E. Philip Horwitz, S.L. Maxwell et al., Analytica Chimica Acta, 310, 63,
(1995).
– S.L. Maxwell III, “Rapid Actinide-Separation Methods”, Radioactivity
and Radiochemistry, 8, No 4, 36, (1997)
• UTEVA method for Pu/U oxides (Metal impurities assay on mixed
oxide or actinide process solutions to remove U/Pu interferences and
characterize materials by ICP-ES and ICP-MS, 1998-1999)
Improvements In Column Extraction
– Process and waste analyses
• Trace actinides in mixed oxide materials (Np, Th, Am extraction for
ICP-MS using TEVA, UTEVA-1998-1999)
• Simultaneous extraction of U, Pu for IDMS assay and isotopics in
mixed oxides - (2000)
– S.L. Maxwell and J. Satkowski, “Rapid Mass Spectrometry for Uranium
and Plutonium”, Radioactivity and Radiochemistry Journal, Vol. 12, No
2, 2001
Recent Column Extraction Applications
• Column Extraction Applications at SRS
– Soil and Fecal Sample Analyses
• Actinides in soil using Diphonix Resin-microwave digestion
– S.L. Maxwell III and S. Nichols, “Actinide Recovery Method for Large
Soil Samples”, Radioactivity and Radiochemistry, 11, No 4, 46, (2000)
• Pu, Am in fecal samples using Diphonix Resin-microwave digestion
and TEVA+TRU Resin, (1999)
– S.L. Maxwell and D. Fauth, “New Fecal Method for Pu and Am”,
Journal of Radioanalytical and Nuclear Chemistry, Vol. 250, No. 1 ,
2001
Recent Column Extraction Applications
• Column Extraction Applications at SRS, contd.
– Bioassay: urine
• Column extraction in Bioassay Lab for Pu, Np, Am, U plus Sr method
using cartridge technology
– S.L. Maxwell III and D. Fauth, “Rapid Column Extraction Methods for Urine”,
Radioactivity and Radiochemistry, 11, No 3, 28, (2000)
Bioassay Urine Methods
• Improve chemical recoveries, improve Th-228 removal
and reduce labor costs/rework
– Pu (+Np when Pu-236 tracer used) on TEVA Resin
– Pu, Np, U, Am, Sr
•
•
•
•
Single two cartridge TEVA/TRU column plus SR Resin
No iron in urine allows novel, stacked TEVA+TRU column
Pu, Np on TEVA; U, Am on TRU cartridge in stacked column
Sr collected, evaporated, redissolved, separated on SR Resin column
Urine Batch: Calcium Phosphate Precipitation
Pu, Np/Am, U, Sr on TEVA/TRU RESIN
(URINE)
1) Adjust to 2.5MHN03 - 1M Al(NO3)3
2) 0.05M Sulfamic Acid + 0.2M Ascorbic Acid
3) 0.4 to 0.5M Sodium Nitrite
Rinse
20 mL 3MHN03
Th Removal
3mL 9MHCI/30mL
8MHCI
Pu Elution
30mL
0.10MHC1 - 0.05MHF - 0.1M NH4l
2mL TEVA Resin
(50-100 um)
4mls 0.02M H2SO4 + 3mls 16M HN03
Evaporate/ash
Electrodeposition
Remove TRU cartridge:
1) Elute Am with
12mL 4M HCI
2) Elute U with
20mL 0.1M ammonium
bioxalate
2.0mL TRU-Resin
(50-100 um)
Collect, evaporate, dissolve in 6M HNO3
SR Resin
TEVA+ TRU Stacked Column: Pu, Np, U, Am
TRU Cartridge: U, Am Stripping
SR Cartridge: Sr-90 Separation
TEVA Pu Tracer Recoveries
500 mL urine sample/ Pu-242 tracer= 1.25 dpm / One TEVA Column
Fe+AA/+NO2
%Recovery (CeF3 microprecipitation)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
110
93.3
92.6
95.2
101.5
99.3
97.7
115.4
107.9
106.8
101.6
102.6
Avg. = 102.0% (7.0% @1s)
% Recovery (Electroplating* )
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
84.4
72.4
69.3
69.6
79.8
84.5
79.1
85.5
84.8
77.0
82.5
Avg. = 79.0 (6.2% @1s)
*Add 4 mL 0.02M H2SO4 to enhance F removal during solution cleanup for plating
TEVA- Np-237 , Pu-236 Recoveries
500 mL urine sample/ Np-237 spike= 1.40 dpm/Pu-236=0.425 dpm
Single TEVA column (CeF3 microprecipitation)
% Pu-236
Recovery
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
94.0
92.5
101
100
111
91.0
91.9
105
109
88.9
Avg. =98.4% (7.9% @1s)
% Np-237
Recovery
***
***
***
***
***
88.1
86.7
102.9
102.0
94.2
Avg. = 94.8% (7.6% @1s)
Additional bias comparison on 24 samples: -1.49% +/- 6% estimate of bias
Bioassay Lab Alpha Counters
Bioassay Lab Gas Proportional Counters:Sr
%bias Np Control Samples
80%
60%
40%
20%
0%
-20%
-40%
-60%
-80%
Bias = -2.5% RSD = 11.0
3067 samples
June 2000 - January 2002
TRU Resin -Am Tracer Recoveries
500 mL urine sample/ Am-243 tracer= 1.55 dpm / TRU cartridge after TEVA
SA+AA/+NO2 / load TEVA and TRU at same time/remove TRU cart./elute Am
% Am-243 Recovery (Electroplating)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
93.2
92.1
107.4
70.3
102.4
103.0
100.2
103.3
102.6
94.7
Avg. =
96.9% (10.6% @1s)
Recent Advances In Urine Method
• Use scrubbed U-232 tracer to minimize Th-228 daughter
added and eliminate need for 2nd TEVA column cleanup
when uranium analyzed with Pu, Np, Am, Sr
• Add boric acid to eliminate adverse effect of trace fluoride
on electroplating/increased tracer recoveries
Th-228 In-Growth After Removal from U-232
Microwave Digestion of Diphonix: Fecal Method
2
Pu on TEVA RESIN
(2nd Column to Remove all Th-228)
• Redissolve in 7.5mL 3M HN03 + 1mL 2.5M Al(NO3)3
• Add 0.5mL 1.5M Ferrous Sulfate + 1mL 1.5M Ascorbic Acid
• Add 1mL 3.5M Sodium Nitrite
• Add 1mL 16M Nitric Acid
Rinse
10mL 3MHN03
Th Removal
3mL 9MHCI/7mL
8MHCI
Pu Elution
20 mL
0.10MHC1 - 0.05MHF - 0.1M NH4l
1mL TEVA Resin
% Bias Plot for DOELAP Proficiency Test
60.0
% Bias
40.0
20.0
0.0
-20.0
-40.0
Pu-238
Urine %Bias
Pu-239 /240
U-234
Fecal %Bias
U-238
Np-237
Acceptable Lower %
Am-241
Sr-90
Acceptable Upper %
% RSD Plot for DOELAP Proficiency Test
50.0
% RSD
40.0
30.0
20.0
10.0
0.0
Pu-238
Urine %Bias
Pu-239 /240
Fecal %Bias
U-234
U-238
Acceptable Upper %
Np-237
Am-241
Acceptable Upper %
Sr-90
Summary
• New rapid column extraction methods have greatly
improved radiochemical separation technology
– process lab support
– bioassay lab applications
– environmental lab work
• Vacuum-enhanced column and cartridge extraction
methods have enhanced lab capabilities
– simpler, faster, less rework, less waste
• Rapid extraction technology continues to advance at the
frontier of radioanalytical chemistry