235U and U and U in Urine by Inductively Coupled Plasma

An Improved Method for the Determination of An Improved Method for the Determination of 235235U and U and 238238U in Urine by U in Urine by

Inductively Coupled PlasmaInductively Coupled Plasma--Mass SpectrometryMass Spectrometry

Sasi S. KannamkumarathSasi S. KannamkumarathOak Ridge Institute for Science and EducationOak Ridge Institute for Science and Education

Oak Ridge, Tennessee 37831Oak Ridge, Tennessee 37831

Govind R. Rao, Benito D. Gonzalez, Roger D. Myers,Govind R. Rao, Benito D. Gonzalez, Roger D. Myers,DeAnna K. Hatmaker, and Myint Thein DeAnna K. Hatmaker, and Myint Thein

Nuclear and Radiological Protection DivisionNuclear and Radiological Protection DivisionOak Ridge National Laboratory*Oak Ridge National Laboratory*

Oak Ridge, Tennessee 37831Oak Ridge, Tennessee 37831

*Managed by UT*Managed by UT--BattelleBattelle, LLC, for the U.S. Department of Energy under contract DE, LLC, for the U.S. Department of Energy under contract DE--AC05AC05--00OR22725.00OR22725.

OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY

AcknowledgementAcknowledgement

Janice M. Rankin&

Gerard F. Payne &


Alpha SpectrometryAlpha Spectrometry

RESOLUTIONRECOVERYANALYSIS TIMELABOR-INTENSIVE WASTE

ISOTOPIC

DISADVANTAGESADVANTAGES

CO-PRECIPITATIONSAMPLE ION EXCHANGE

COUNTING

ELECTRODEPOSITION


DESIRED CHARACTERISTICS

• FAST

• ACCURATE

• ISOTOPIC

• COST-EFFECTIVE

ALTERNATE METHODSALTERNATE METHODS

FLUORIMETRYFLUORIMETRY

KPAKPA

ICPICP--MSMS

ADVANTAGESADVANTAGES• Rapid • Better than alpha spectrometry• Isotopic• Cost-effective • Less labor• Waste reduction

LIMITATIONSLIMITATIONS• 235U & 238U only (bioassay)

ADVANTAGESADVANTAGES• Rapid and relatively simple• Sensitive to low levels of uranium• Chemical separations not needed

LIMITATIONSLIMITATIONS• Uranium must be present as U(VI)• Not isotopic• Potential contamination from reagents• Quenching• Interferences

Chromate Suspended particles


Relative Detection SensitivitiesRelative Detection Sensitivities

6.6 X 10714.9 X 1013232u

2.8 X 10412.1 x 1010233U

1.9 x 10411.4 x 1010234U

6.5 x 10014.8 x 106235U

1.9 x 10211.4 x 108236U

117.4 x 105238U

5.1 x 10713.8 x 1013238Pu

ActivityMass

Relative Detection Sensitivities

Specific

Activity

(dpm/g)

Nuclide


• Perkin Elmer DRC-e• 240-Sample CETAC ASX-510 Auto Sampler• Cross Flow II Nebulizer – Ryton Scott Spray Chamber• Quadrupole Mass Spectrometer


IonizationIonization ExtractionExtraction SelectionSelectionIonizationIonization ExtractionExtraction SelectionSelection



4000 msIntegration time

400 msDwell time per AMU

Peak hoppingScan mode

235U, 236U, 238UIsotopes monitored

NickelSampling/skimmer cones

RytonTM Scott-type Spray chamber

Cross Flow IINebulizer

0.92 L minCarrier gas flow rate

1.2 L/minAuxiliary gas

15.0 L/minPlasma gas flow rate

1100 W RF power

Operating ParametersOperating Parameters

Instrumental ParametersInstrumental Parameters


Sample PreparationSample Preparation

Add conc. HNO3to make 5% HNO3

Add H2O2to make 2% H2O2

Heat

30 minTo analysis


AnalysisAnalysis

1-g digestedsample

10 gDiluteDilute

5% HNO5% HNO33

ICP-MSanalysis

1-g calibrationstandard

10 gDiluteDilute

5% HNO5% HNO33

ICP-MS calibration


dpm/g

Net

Co

un

ts

y = 6E+06xR2 = 0.9993

0.E+00

5.E+04

1.E+05

2.E+05

0.000 0.005 0.010 0.015 0.020 0.025

CalibrationCalibration: : 238238UU


Sample #

%B

ias

Synthetic Urine Sample Real Urine Sample

Sample #

%B

ias

Initial ResultsInitial Results

-20

-15

-10

-5

0

5

10

0 2 4 6 8 10 12

-20

-15

-10

-5

0

5

10

0 1 2 3 4 5 6

Synthetic urine Natural urine238238UU


Internal StandardInternal Standard

• Surrogate element expected to mimic the behavior of the analyte of interest.

• Must not normally be present in the samples being analyzed.

• Must not interfere with the analyte of interest.

• Better accuracy if same internal standard solution is used in calibration and sample analysis.

• Ratio of analyte signal to internal standard signal is independent of variations in flow rates, sample introduction efficiency, plasmaconditions, detector response, matrix effects, etc.

• Typical standards: Bi, Re, Rh, Ir, etc., used in uranium analysis.


Analysis with Internal StandardAnalysis with Internal Standard

1-g digestedsample

10 g ICP-MSanalysis


10 g

DiluteDilute

5% HNO5% HNO33++

internal internal standardstandard

ICP-MS calibration

DiluteDilute

5% HNO5% HNO33++

internal internal standardstandard


Synthetic urine Natural urine

209209BiBi Internal Standard CorrectionInternal Standard Correction%

Bia

s

-20

-15

-10

-5

0

5

10

0 1 2 3 4 5 6

Without Internal Standard

With Internal Standard

-20

-15

-10

-5

0

5

10

0 2 4 6 8 10 12

Without Internal Standard

With Internal Standard

238238UU


Blind Spiked Samples (ISP) Internal Blind Spiked Samples (ISP) Internal Standard: Standard: 209209BiBi

dp

m/

sam

ple

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 5 10 15 20 25 30 35 40

Average of 7 measurements each


-12

-8

-4

0

4

8

12

0 5 10 15 20 25 30 35 40

% B

ias

238238UU


Other Internal StandardsOther Internal Standards%

Bia

s

Re Re RhRh

-20

-15

-10

-5

0

5

0 20 40 60 80 100 120 140 160 180 200

-15

-10

-5

0

5

10

15

0 20 40 60 80 100 120 140 160 180 200

238238UU


Analysis with Internal StandardAnalysis with Internal Standard

1-g digestedsample

10 g ICP-MSanalysis


10 g

DiluteDilute

5% HNO5% HNO33++

236236U internal U internal standardstandard

ICP-MS calibration

DiluteDilute

5% HNO5% HNO33++

236236U internal U internal standardstandard


y = 0.0789xR2 = 0.9999

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10 12

CALIBRATION WITH INTERNAL STANDARD CALIBRATION WITH INTERNAL STANDARD 236236UU

y = 0.0129xR2 = 0.9979

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0 0.1 0.2 0.3 0.4 0.5 0.6

2385

236( / ) 10

( )U dpm g

U g⎡ ⎤

×⎢ ⎥⎣ ⎦

2355

236( / ) 10

( )U dpm g

U g⎡ ⎤

×⎢ ⎥⎣ ⎦


-15

-10

-5

0

5

10

15

0 1 2 3 4 5 6 7 8 9 10

U-238U-235

Blind Spiked Samples (ISP) Internal Blind Spiked Samples (ISP) Internal Standard: Standard: 236236UU

%B

ias


ICPICP--MS MS vsvs Alpha SpectrometryAlpha Spectrometry%

Bia

s

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Alpha Spec

ICP-MS

238238UU


Analysis ProtocolAnalysis Protocol

Daily Performance Check

CVS

Calibration

Memory Blank

ICS

LRBs

LCS

QCS

CCB

10 Samples

238U cts/s ≥ 150,000

Ba++/Ba ≤ 0.05

CeO/Ce ≤ 0.05

Calibration BlankCalibration Standard 1

..

..Calibration Standard 6

(R2) ≥ 0.99

Activity <1st standard of calibration curve

CVS

CCB

10 Samples

CVS CCB Matrix spike

Instrument Check Standard

Activity +20% of expected value

Calibration Verification Standard


Continuing Calibration BlankActivity

<1st standard of calibration curve

Laboratory Reagent Blank

Laboratory Control Sample


Quality Control Sample


Includes 1 duplicate

After every 10 sample




Laboratory Reagent Blank (LRB)Laboratory Reagent Blank (LRB)

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

0.005

0 5 10 15 20 25 30 35

U-238U-235

dp

m/

L


CalculationsCalculations

−− −−

− −

⎛ ⎞= × × − × −⎜ ⎟

⎝ ⎠5238 238

238236 236

10

k: Calibration ConstantDF: Dilution FactorC: Sample CountsB: Calibration Blank Counts

U UU

U U

C BA k DF LRB

C B

238

235

( / ) 4.65

: 0.005 / (1.5 / )

: 0.007 / (6.8 / )

LRBMDA dpm L s

U dpm L ng L

U dpm L ng L

= ×


Final WordsFinal WordsUse of 236U as an internal standard has improved reproducibility.

Granted Technical Equivalency by DOELAP.

Additional ideas being explored:

• Improve MDA for 235U by clean-up chemistry.

• Fecal samples?

• 232Th?

Alpha spectrometry continues to be used for other uranium isotopes.

Documents

235U and U and U in Urine by Inductively Coupled Plasma