Tc-99 Analysis in Air Tc-99 Analysis in Air Filters, An Approach to Filters, An Approach to

Eliminate High BiasEliminate High Bias

Mitch AbbateMitch AbbateBarringer LaboratoriesBarringer Laboratories

Golden, ColoradoGolden, Colorado

TechnetiumTechnetium Discovered in 1937 by Segrè and Discovered in 1937 by Segrè and

PerrierPerrier First Element Produced ArtificiallyFirst Element Produced Artificially Fission by-productFission by-product 213,000 Year Half-life, Beta Emitter213,000 Year Half-life, Beta Emitter Very SolubleVery Soluble Can Cause and Help Diagnose CancerCan Cause and Help Diagnose Cancer

Barringer Analysis of Tc-99Barringer Analysis of Tc-99 Historically, Tc-99 extracted into TBPHistorically, Tc-99 extracted into TBP

– Messy/ Difficult to meet TAT and MDLMessy/ Difficult to meet TAT and MDL– Mixed Radioactive/ Organic WasteMixed Radioactive/ Organic Waste

Evaluation of Eichrom’s TEVA ResinEvaluation of Eichrom’s TEVA Resin– Simpler ProcedureSimpler Procedure– No Mixed WasteNo Mixed Waste– Concern over False Positives with Air Concern over False Positives with Air

FiltersFilters

Eichrom TEVA ProcedureEichrom TEVA Procedure Oxidize Tc to TcOOxidize Tc to TcO44

--, Tc(VII), Tc(VII) Pass sample through TEVA Resin Pass sample through TEVA Resin

(pH=2)(pH=2) Rinse Resin with 0.01 N HNORinse Resin with 0.01 N HNO33 Transfer Resin to LSC VialTransfer Resin to LSC Vial Add CocktailAdd Cocktail Count via LSCCount via LSC

False PositivesFalse Positives Air Filter SamplesAir Filter Samples

– Pb-210 Possible CulpritPb-210 Possible Culprit Pb-210 in U-238 Decay ChainPb-210 in U-238 Decay Chain

– Beta Emitter/ Interference with Tc-99Beta Emitter/ Interference with Tc-99

U U-238 U-2344.4680E+09 99.84% 2.4450E+05

92 y Pa234m y

Pa 1.17m

0.16%

91 Pa234

Th Th-234 6.7h Th-230

90 24.1d 77000y

Ac

89

Ra Ra-226

88 1600y

Fr

87

Rn Rn-222

86 3.8235d

At At-218

85 0.02% (~2s)

Po Po-218 Po-214 Po-2101.637E-04 138.378

84 3.05m 99.979% s ~100% d

Bi Bi-214 Bi-21099.98%

83 19.9m ~100% 5.013d

Pb Pb-214 Pb-210 Pb-2060.021% (1.3E-4%)

82 26.8m 22.26y STABLE

Tl Tl-210 Tl-206(1.7E-6%)

81 1.3m (4.19m)

Hg Hg-206

80 (8.5m)

Pb-210?Pb-210? Spiked Samples with 500 pCi Pb-210Spiked Samples with 500 pCi Pb-210

– Up to 30% Activity Found on TEVA Resin Up to 30% Activity Found on TEVA Resin via LSC via LSC

Tried ppt. Pb w/ FeOHTried ppt. Pb w/ FeOH– Slight Activity ReductionSlight Activity Reduction

Recounted Original SamplesRecounted Original Samples– Significant Activity DropSignificant Activity Drop– Bi-210 Half-Life 5.01 daysBi-210 Half-Life 5.01 days

Bi-210Bi-210 Ca(POCa(PO44))22 ppt. ppt.

– Good Results but Too Time Good Results but Too Time ConsumingConsuming

Bi uptake in HF on Strong Base Bi uptake in HF on Strong Base ResinResin– No AdsorptionNo Adsorption

Ref. J.P. Feris, Anal. Chem., 32, 520 Ref. J.P. Feris, Anal. Chem., 32, 520 (1960)(1960)

Re (VII) UptakeRe (VII) Uptake

1

10

100

1000

0 5 10 15 20[HF]

Log

Dist

. Coe

ff.

[HF]

HF EvaluationHF Evaluation HF Added to Load SolutionHF Added to Load Solution

– PrecipitationPrecipitation Rinse with HFRinse with HF

– Bi Removed to Near BackgroundBi Removed to Near Background– Some Tc-99 Yield ReductionSome Tc-99 Yield Reduction

Rinse with HF/Nitric AcidRinse with HF/Nitric Acid– Near 100% Tc-99 Recoveries: no Bi or PbNear 100% Tc-99 Recoveries: no Bi or Pb– TSIE’s best with 5 N HF although 1 N OKTSIE’s best with 5 N HF although 1 N OK

New Air Filter MethodNew Air Filter Method Tc-99 Leach w/ 1 N NitricTc-99 Leach w/ 1 N Nitric HH22OO2 2 + Heat to Insure TcO+ Heat to Insure TcO44

--

Dilute to < 0.3 N Nitric AcidDilute to < 0.3 N Nitric Acid Load on TEVA Resin (100-150µ)Load on TEVA Resin (100-150µ) 25 mL Rinse w/ 0.01 N Nitric25 mL Rinse w/ 0.01 N Nitric 20 mL Rinse w/ 5 N HF-0.01 N Nitric20 mL Rinse w/ 5 N HF-0.01 N Nitric 25 mL Rinse w/ 25 mL 0.01 N Nitric25 mL Rinse w/ 25 mL 0.01 N Nitric Direct Addition of Resin to LSC CocktailDirect Addition of Resin to LSC Cocktail After Dark Adaptation: LSC CountingAfter Dark Adaptation: LSC Counting

TEVA RESIN

Barringer Vacuum BoxBarringer Vacuum Box

SummarySummary Method Used for All Sample TypesMethod Used for All Sample Types

– Tc-99 yields average >91%Tc-99 yields average >91% Batch of 18 Samples (+ 6 QC)Batch of 18 Samples (+ 6 QC)

– 6 Hours Total Processing Time6 Hours Total Processing Time– Two Times Faster than TBP MethodTwo Times Faster than TBP Method

Meeting Required Detection LimitsMeeting Required Detection Limits Eliminate Mixed WasteEliminate Mixed Waste Eliminate RerunsEliminate Reruns

AcknowledgementAcknowledgement Jim Preston, Barringer LaboratoriesJim Preston, Barringer Laboratories Anil Thakkar and Larry Jassin, Anil Thakkar and Larry Jassin,

EichromEichrom Phil Horwitz and Andy Bond, PGRF Phil Horwitz and Andy Bond, PGRF