New extraction methods for urine and fecal samples
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New Extraction Methods for Urine and Fecal Samples. Sherrod L. Maxwell David J. Fauth Savannah River Site. Bioassay Urine Methods. Improve chemical recoveries, improve Th-228 removal reduce acid waste and labor costs/rework

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New Extraction Methods for Urine and Fecal Samples

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New Extraction Methods for Urine and Fecal Samples

Sherrod L. Maxwell

David J. Fauth

Savannah River Site


Bioassay Urine Methods

  • Improve chemical recoveries, improve Th-228 removal reduce acid waste and labor costs/rework

  • Replace anion exchange methods and use vacuum-enhanced extraction chromatography

    • 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 single 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


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

Th Removal

3mL 9MHCI/30mL

8MHCI

Rinse

15mL 3MHN03

Pu Elution

30mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

4mls 0.02M H2SO4 + 3mls 16M HN03

2mL TEVA Resin

(50-100 um)

Evaporate

2nd TEVA

Column

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 8M HNO3

SRS Resin


Pu on TEVA Resin (Urine or Fecal)

(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.M sodium nitrite

  • Add 1mL 16M nitric acid

Th Removal

2mL 9MHCI/8mL

8MHCI

Rinse

10mL 3MHN03

Pu Elution

15mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

1mL TEVA Resin


TEVA Pu Tracer Recoveries

  • 500 mL urine sample/ Pu-242 tracer = 1.25 dpm/One TEVA Column Fe+AA/+NO2

%Recovery% Recovery

(CeF3 microprecipitation)(Electroplating*)

1)1101) 84.4

2)93.32) 72.4

3)92.63) 69.3

4) 95.24)69.6

5) 101.55) 79.8

6)99.36) 84.5

7)97.7 7) 79.1

8) 115.48) 85.5

9) 107.99) 84.8

10)106.810)77.0

11)101.611)82.5

12)102.6

Avg. = 102.0% Avg. = 79.0

*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

  • SA+AA/+NO2/Single TEVA column (CeF3 microprecipitation)

% Pu-236% Np-237

Recovery Recovery

1)94.0*** 2) 92.5*** 3)101*** 4) 100*** 5) 111*** 6) 91.088.17) 91.9 86.7

8) 105 102.99) 109 102

10)88.994.2

Avg. = 98.4% Avg. = 94.8%


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) 93.2

2) 92.1

3)107.4

4) 70.3

5)102.4

6)103.0

7)100.2

8)103.3

9)102.6

10)94.7

Avg. = 96.9%


TRU Resin-U Tracer Recoveries

  • 500 mL urine sample/U-232 tracer = 0.554 dpm/TRU cartridge after TEVA

  • SA+AA/+NO2 /load TEVA and TRU at same time/remove TRU cart./elute U

    % U-232 Recovery (Electroplating*)

    1) 97.9

    2) 74.1

    3)85.6

    4) 102.9

    5)90.6

    6)83.1

    7)57.7

    8)81.0

    9)80.4

    10)93.3

    Avg. = 84.7%


Accuracy on Spiked Urine Samples

Pu-238Pu-239Am-241Sr-90

Levels0.145-4.95 0.022-3.62 0.55-3.5 dpm/L5.4-188

dpm/L dpm/L dpm/LpicoCi/L

Number SamplesN=12N=12N=7N=6

Bias-14.7%+12.4%-3.4%-4.8%

Blanks0.016 (N=8)0.012 (N=8)0.007 (N=23)-0.05 (N=4)

DOELAP criteria (Bias: -25% to +50%)


Accuracy on Spiked Urine Samples

U-234U-238U-235

Levels0.197-2.04 0.147-3.02

dpm/Ldpm/L

Number SamplesN=4N=4

Average Bias+7.8%+1.5%

Blanks0.008 (N=12)0.012 (N=10)-0.001 (N=12)

DOELAP criteria (Bias: -25% to +50%)


Need for Improved Fecal Analysis for Pu and Am at SRS

  • Background

    • SRS incident in FB-Line

    • Need for improved fecal analysis

      • Complete dissolution of any plutonium oxide present

      • Effective Th-228 removal

    • Problems with microwave vessels

      • Corrected pressure release valve problems

      • Completed FB-Line incident samples


New Approach

  • Old method:

    • Residual undissolved solids in final nitric acid solution

    • Solids contained some activity

  • New approach:

    • Continue to use HNO3-HF dissolution/multiple digestion

    • Apply diphonix resin technology

    • Used successfully for large soil samples

    • Allows loading from HCl-HF solutions

    • Digest Diphonix using SRS microwave method

    • Apply Eichrom sequential column method


Method Details

  • Microwave digestion of Diphonix resin

    • Microwave to 190C for 15 minutes in 10 mL 16M HNO3

    • Change disk & microwave to 200C for 20 minutes in 10 mL 16M HNO3

    • Change disk & microwave to 215C for 25 minutes in 10 mL 16M HNO3

    • Add 3.5 mL 30wt% H2O2 and microwave to 21OC for 10 minutes in 10 ml 16M HNO3

  • Final wet ashing of resin

    • Ash with 30wt% H2O2 four times

    • Ash with HNO3 + H2O2 one time, or until does not get any whiter


Method Details

  • Preparation for Pu, Am column separation

    • Dissolve in 6 mLs of 5M to 6M HNO3

    • Add 6 mLs 2 to 2.5M aluminum nitrate

    • Solution ready for TEVA + TRU resin column extraction

  • Preparation for Pu, Am column separation

    • Valence adjustment for Pu

      1)Add 1 mL 1.5M ferrous sulfate + 1 mL 1.5M ascorbic acid, wait 3 min.

      2)Add 1 mL 3.5M sodium nitrite


Method Details

  • Separate Pu using TEVA column

    • Th removal 9M HCl+8M HCl

    • Use 2nd 1 mL TEVA column to remove all Th-228

    • High retention/good clean-up

  • Separate Am using TRU column

    • Collect load plus rinse from 1st TEVA column

    • Evaporate to dryness

    • Redissolve in 15 mls 3 M HNO3

    • Add 2 mLs 1.5M sulfamic acid + 5 mls 1.5M ascorbic acid

    • Load to TRU resin


Rinse

15 to 20mL 3MHNO3

Pu, Am on TEVA + TRU Resin (Fecal Method)

Adjust to 2.5MHN03 -1M Al(NO3)3

1)0.1M ferrous sulfate

2)0.25M sodium nitrite

Th Removal

3mL 9MHCI/30mL

8MHCI

Pu Elution

30mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

2mL TEVA Resin

(50-100 um)

4mls 0.02 H2S04/3mLs 16MHN03

evaporate ash H2O2 1mL

TEVA column to ensure

complete Th-288 removal

-evaporate

-redissolve in 3M HNO3

-add sulfamic acid + ascorbic acid

Am Elution

3mL 9MHCI/15mL -4M HCI

Rinse

1)5mL

2.5M HNO3-0.1M

ascorbic acid

2)5mL 3M HNO3

0.1M NaNO2

3)10mL 3M HNO3

2ml TRU resin

(50-100 um)


Pu on TEVA Resin (Urine or Fecal)

(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.M sodium nitrite

  • Add 1mL 16M nitric acid

Th Removal

2mL 9MHCI/8mL

8MHCI

Rinse

10mL 3MHN03

Pu Elution

15mL

0.10MHC1 - 0.05MHF - 0.1M NH4l

1mL TEVA Resin


TEVA+TRU Pu/Am Tracer Recoveries

Fecal samples: 1.5-4 grams ash/Pu-242 spike = 1.26 dpm

TEVA column+ 2nd 1 mL TEVA column

Fecal blank 1A 75.3 91.5

Fecal blank 1B 68.5103.1

Fecal blank 272.181.5

Fecal blank 3 A75.689.2

Fecal blank 3 B79.395.8

Fecal blank 478.4100.8

Avg.74.993.7

Column Reagent

blank 74.490.8

Column Reagent

blank 82.889.8

Avg.78.690.3

%Pu-242 Recovery%Am-243 Recovery


Method Validation

  • Analysis of multiple sample blanks

    • Complete dissolution

    • High tracer recovery

    • Good Th-228 removal

  • Analysis of artificial fecal sample spiked with Pu oxide from RESL-Idaho

    • Test plan to validate versus known Pu levels


Assay of of DOE-RESL Fecal Standards

Pu-239 Am-241

(picocuries)% Bias (picocuries) %Bias

DOE-RESL values2.182.76

SR-194 #11.8602.405

SR-194 #21.8412.608

Avg.1.850-15.1%2.507-9.2%

SR-234 #12.0622.488

SR-234 #22.1392.335

Avg.2.101-1.4%2.411 -10.7%


Plutonium Results on Leached EML QAP Soil Samples

Smp. Wt.Pu-242 TracerPu-238Pu-239Recovery(dpm/g)(dpm/g)

9403 EML Value--------0.6720.216

9.957g90%0.6640.200

10.100g80%0.6630.223

14.980g97%0.6320.211

Avg. 89%0.653 (-2.8%)0.211 (-2.4%)


Pu Results on Fused EML QAP Soil Samples

Smp. Wt.Pu-242 TracerPu-238Pu-239

Recovery(dpm/g)(dpm/g)

9609 EML Value--------0.0681.31

10.00g73%0.0801.47

10.00g82%0.0471.43

10.00g85%0.0531.41

10.00g80%0.0631.39

Avg.80%0.061 (-10%)1.42 (+11%)


Am Results on Fused EML QAP Soil Samples

Smp. Wt.Am-243 TracerAm-241 Recovery(dpm/g)

9609 EML Value--------0.81

10.00g84%0.94

10.00g87%0.83

10.00g73%0.95

Avg.80%0.90 (+11%)


Summary

  • Urine

    • Pu, Np and Am, U on two cartridge TEVA-TRU column with Sr-90 on SR resin after evaporation

    • High recovery/good Th-228 removal

    • Rapid column methods for urine will result in significant time/cost savings/waste reduction

  • Fecal

    • New fecal method dissolves Pu oxide using HNO3 -HF

    • Diphonix method has improved fecal analysis at SRS

      • total dissolution

      • remove Pu, Am from HCl-HF sample solutions

      • excellent Th-228 removal/good results on DOE-RESL samples


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