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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 &
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Alpha SpectrometryAlpha Spectrometry
RESOLUTIONRECOVERYANALYSIS TIMELABOR-INTENSIVE WASTE
ISOTOPIC
DISADVANTAGESADVANTAGES
CO-PRECIPITATIONSAMPLE ION EXCHANGE
COUNTING
ELECTRODEPOSITION
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
• Perkin Elmer DRC-e• 240-Sample CETAC ASX-510 Auto Sampler• Cross Flow II Nebulizer – Ryton Scott Spray Chamber• Quadrupole Mass Spectrometer
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
IonizationIonization ExtractionExtraction SelectionSelectionIonizationIonization ExtractionExtraction SelectionSelection
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Sample PreparationSample Preparation
Add conc. HNO3to make 5% HNO3
Add H2O2to make 2% H2O2
Heat
30 minTo analysis
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
AnalysisAnalysis
1-g digestedsample
10 gDiluteDilute
5% HNO5% HNO33
ICP-MSanalysis
1-g calibrationstandard
10 gDiluteDilute
5% HNO5% HNO33
ICP-MS calibration
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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.
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Analysis with Internal StandardAnalysis with Internal Standard
1-g digestedsample
10 g ICP-MSanalysis
1-g calibrationstandard
10 g
DiluteDilute
5% HNO5% HNO33++
internal internal standardstandard
ICP-MS calibration
DiluteDilute
5% HNO5% HNO33++
internal internal standardstandard
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
-12
-8
-4
0
4
8
12
0 5 10 15 20 25 30 35 40
% B
ias
238238UU
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
Analysis with Internal StandardAnalysis with Internal Standard
1-g digestedsample
10 g ICP-MSanalysis
1-g calibrationstandard
10 g
DiluteDilute
5% HNO5% HNO33++
236236U internal U internal standardstandard
ICP-MS calibration
DiluteDilute
5% HNO5% HNO33++
236236U internal U internal standardstandard
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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⎡ ⎤
×⎢ ⎥⎣ ⎦
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
-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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
Activity +10% of expected value
Continuing Calibration BlankActivity
<1st standard of calibration curve
Laboratory Reagent Blank
Laboratory Control Sample
Activity +10% of expected value
Quality Control Sample
Activity +30% of expected value
Includes 1 duplicate
After every 10 sample
After every 10 sample
After every 20 sample
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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
= ×
OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY
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.