in-situ trace element and isotope determinations with ... · pdf fileicp-ms. laser source...
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M. TiepoloM. TiepoloC.N.R.C.N.R.--Istituto diIstituto di GeoscienzeGeoscienze ee GeorisorseGeorisorse Sezione di Pavia,Sezione di Pavia, ItalyItaly
Thanks to: C. Bouman, B. Narcisi, F. Schiavi, M. Palenzona, J-L. Paquette, M.R. Renna, R. Tribuzio, R. Vannucci, A. Zanetti
InIn--situ trace element and isotope situ trace element and isotope determinations with laser ablationdeterminations with laser ablation
(LA)(LA)--HRHR--ICPMS & (LA)ICPMS & (LA)--MCMC--ICPMSICPMS
GeochemistryGeochemistry of the of the solidsolid EarthEarth
0.1
1
10
100
Li KBaRbThUNbTaLaCeSrPbNdSmEuGdZrHfTiDyYYb
Am
ph
/C1
Radiogenic & Stable isotopesTrace elements
Geochronology
Trace element 5-10%
Approximate scale of Approximate scale of precisionprecision
Geochronology (U-Pb) 1-2%
Isotope geochemistry << 1%
Laser ablation (LA)Laser ablation (LA)--ICPICP--MSMSLaser sourceLaser source
•• High spatial resolutionHigh spatial resolution•• Efficient ablation on most of Efficient ablation on most of
materialsmaterials
•• High ionization efficiency of High ionization efficiency of the ICP sourcethe ICP source
•• High sensitivityHigh sensitivity
ICP mass spectrometerICP mass spectrometer
+
Earth Sciences, environmental sciences, biological sciences, forensic sciences, semiconductors
Trace element and isotopic determinations
Examples of materials where the Examples of materials where the in situin situ approach is requiredapproach is required
1 cm1 cm
100 µm100 µm 100 µm 100 100 µµmm
Tree ring analysesRocks & Minerals Volcanic ashes
Laser wavelengths and laser pitsLaser wavelengths and laser pits266 nm Nd:YAG laser 193 nm ArF Excimer laser
50 µm 100 µm
Ablation efficiency is a function of:-Laser wavelength (E193 > E266)-Material (UV transparency)
The ablation processThe ablation process
100 µm
266 nm5.0 mW20Hz
BCR-2Basaltic glass
Sensitivity in laser ablationSensitivity in laser ablation(Dry plasma)(Dry plasma)
Signal from laser ablation is about 100,000 times lower than that from solution nebulisation.
example
1x109 cps/ppm In → 1x104 cps/ppm In
This enormous difference is mainly related to the poor efficiency of the ICP torch in ionising the
particulate produced by laser ablation.
The laser ablation signalThe laser ablation signal1. Highly transient (signal decrease with time/depth)2. Limited in time (~ 2 minutes of signal)
100
1000
10000
100000
1000000
10000000
0 50 100 150 200scans
cps
44Ca
93Nb
208PbBackground
Signal
Signal acquisitionSignal acquisitionSimultaneousSimultaneous vs. vs. SequentialSequential
Multi-collector
Single collector∆t
(44Ca/208Pb)m = f [∆t ; (44Ca/208Pb)S]
Requirements of the ICPMSRequirements of the ICPMS
• High sensitivity (high signal/background ratio)
• Multi–element analysis
High scan speed
• Isotope analysisHigh abundance sensitivityFlat top peaks (Possibly) multi collectors
ICPMS and applicationsICPMS and applications
• Q-ICP-MS → highest scan speed– Multi-element analysis
• HR-ICPMS → high sensitivity – relatively high scan speed – flat top peaks
– Multi element analysis (depleted samples)– Basic isotope analysis (Pb geochronology)
• MC-ICP-MS → high sensitivity - multi collector – no dynamic scan– Advanced isotope analysis– No multi element analysis
SINGLE COLLECTOR SINGLE COLLECTOR HIGH RESOLUTION HIGH RESOLUTION
(HR)(HR)--ICPMSICPMS
Multi element analyses withMulti element analyses withLALA--HRHR--ICPMSICPMS
Nd:Yag 266 nm ArF Excimer 193 nm
Element I(ThermoFinnigan)
Upgraded to Element II for:• Capacitive decoupling torch• Magnet• Magnet field regulator
Layout of the HRLayout of the HR--ICPMSICPMS
from ThermoFinnigan
Response curveResponse curveIsotopic abundance normalizedIsotopic abundance normalizedC
ps/
pp
m
1.E+03
1.E+04
1.E+05
Mg25
Si29
Ca43
Ca44
Sc45
Ti49
V51
Cr53
Rb85
Sr88
Y89
Zr90
Nb93
Cs133
Ba137
La139
Ce140
Pr141
Nd146
Sm149
Eu151
Gd157
Tb159
Dy163
Ho165
Er167
Tm169
Yb173
Lu175
Hf177
Ta181
Pb208
Th232
U238
Conventional torch
Capacitive Decoupling torch
In He ablationLaser frequency: 10HzLaser Power 2.2 mW 40 µm spot size
NIST 612NIST 612
“High power “High power magnetmagnet fieldfield regulatorregulator””
0.000
0.200
0.400
0.600
0.800
1.000
1.200
0 50 100 150 200 250
mass (a.m.u.)
Set
tlin
g T
ime
/ a.m
.u. (
ms)
from ThermoFinnigan
m/z 7-238 230 msm/z 7-238 75 ms
Old field regulator
New field regulator
“Flat top” peaks“Flat top” peaks
207Pb
208Pb
Multi element determinations (Low Res.)Multi element determinations (Low Res.)
Scan time: 624 ms7Li
25Mg29Si
43Ca51V
85Rb
133Cs
157Gd
→ 44Ca→ 45Sc → 49Ti→ 53Cr→ 59Co
→ 88Sr→ 89Y → 90Zr → 93Nb
→137Ba→ 139La → 140Ce → 141Pr →146Nd → 149Sm→ 151Eu
→159Tb→ 163Dy → 165Ho → 167Er →169Tm → 173Yb→ 175Lu → 177Hf → 181Ta
isotope6Li7Li9Be11B
25Mg29Si44Ca
6Li → 44Ca
Total scan time: 196 ms Acquisition efficiency: 60%
B-scan
E-scan
7Li → 238U (36 masses)6Li
208Pb →232Th→ 238U
All masses are almost free from interferences and XO+/X+ ratio < 1%
Data Data acquisitionacquisition 1 minute Background – 1 minute Signal
Standard NIST 610/612
Standard NIST 610/612
7 unknown
Reference material (BCR-2
8 unknown
Standard NIST 610/612
Standard NIST 610/612
7 unknown
RSFIIC
C STDi
SAMPi
STDiSAMP
i ⋅⋅
=
SAMPis
STDis
SAMPis
STDis
CIICRSF ⋅
=
PrecisionPrecisionUSGS - BCR-2 (basalt glass)
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
Sc45
Ti49 V51Cr53Co5
9Rb8
5Sr88 Y89Zr90Nb9
3Cs1
33Ba1
37La
139
Ce140
Pr141
Nd146
Sm149
Eu151
Gd157
Tb159
Dy163
Ho165
Er167
Tm169
Yb173
Lu17
5Hf17
7Ta1
81Pb2
08Th2
32U23
8
Pre
cis
ion
(1r.
s.d
. %
)
50 µm 10Hz10 µm 10Hz
193 ArF Excimer laser18 % -
4% -
AccuracyAccuracy(extended trace elements)USGS - BCR-2 (basalt glass) MPI-DING GOR 128-G
40 µm spot size
Reference value (ppm)1 10 100 1000
Mea
sure
d va
lue
(ppm
)
1
10
100
1000
Lu
TaTb
Ho
YbHf
Tm
Cs
Er
U Eu
Gd DyTh
Sm
PbNb
Pr Li
Nd
Cr
La
Ce
Y
RbSc
Co
Zr
Sr
V Ba 40 µm spot size
Reference value (ppm)0.001 0.01 0.1 1 10 100
0.001
0.01
0.1
1
10
100
Th
UTa
PrLa Eu
TbTm
Lu
Hf
Ho
Hf
Sm
Nd
Nb
Ba
Gd
Er
Dy
Yb
Rb
Sc
SrYZr
Cs
Pb
AccuracyAccuracy Light lithophile elements
reference value (ppm)0.1 1 10 100
mea
sure
d va
lue
(ppm
)
0.1
1
10
100
LithiumBerylliumBoron
Nist 616
Nist 612
StHs6/80-GGOR 128-G
GOR 132-G
T1-GML3B-G
T1-G
StHs6/80-G
ML3B-G
Limits of detection (Limits of detection (3σRnet/S)1 ppm
1 ppb
NIST 61250 µm - 2.8 mW
In He ablationLaser frequency: 10Hz
Spot size
5 µm
1
0,1
0,01
0,001
0,0001
0,00001Li Sc Ti V CrCoRb Sr Y ZrNbCs Ba LaCe Pr NdSmEuGdTbDyHo ErTmYbLu Hf Ta Pb Th U
Limits of detection (LLE)Limits of detection (LLE)
0.000
0.200
0.400
0.600
0.800
1.000
1.200
66LiLi 77LiLi 99BeBe 1111BB
limits
of d
etec
tion
(lim
its o
f det
ectio
n ( p
pmppm
))
This work 266 nm (40 µm spot)This work 213 nm (40 µm spot)Gao et al., 2002 (60 µm spot)Kurosawa et al., 2002 (80 µm spot)
1 ppm
Q-ICPMS
Clinopyroxene from forearcperidotites from Western Pacific
Ocean0.001
0.01
0.1
1
10
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Y Er Tm Yb Lu
Cpx
/C1
Clinopyroxene from Zagadochnaya kimberlite (Siberian craton of Yakutia, Russia)
0.1
1
10
100
1000
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Y Er Tm Yb Lu
Cpx
/C1
Z1-5
Z3-4
Volcanic ash in Ice cores from Volcanic ash in Ice cores from Antarctica (5Antarctica (5µµm m –– 193 nm)193 nm)
0.01
0.10
1.00
10.00
100.00
1000.00
Ba Rb Th U Nb Ta La Ce Sr Nd Sm Zr Hf Ti Dy Y Yb
N-M
OR
B n
orm
alis
ed
EPICA ashes
APPLICATIONSAPPLICATIONS::1) Geological samples
APPLICATIONSAPPLICATIONS::2) Human and animal bones
Con
cen
trat
ion
(p
pm
)
HumanHumanHorseHorse DogDog Roman age
1000
100
10
1
0,1
0,01Li Sc Ti V Cr Co Rb Sr Y Zr Nb Cs Ba La Ce Pr Nd Sm Pb Th U
APPLICATIONSAPPLICATIONS::3) Tree rings
0,0100
0,1000
1,000018
80
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Nor
mal
ised
to
25M
g
Pb
oakoak fromfrom “Parco “Parco del Ticino”del Ticino”
18802000
2000
UU--ThTh--Pb Pb GeochronologyGeochronology(LA)(LA)--HRHR--ICPICP--MSMS
•• 238238U U →→ 206206Pb Pb •• 235235U U →→ 207207Pb Pb •• 232232Th Th →→ 208208PbPb
ZirconZircon –– MonaziteMonazite
ZirconZircon –– 213 213 nm
0.080
0.084
0.088
0.092
0.096
0.100
0.104
0.108
0.62 0.66 0.70 0.74 0.78 0.82 0.86 0.90
207Pb/235U
206 P
b/23
8 U
500
540
580
620
Zircon GRMTIMS: 577 ± 8 Ma
σ
573 ± 4.4 (2573 ± 4.4 (2σσ) Ma) Ma
40 µm
nm
InternalInternal precisionprecision (2(2σσ) : 1.0%) : 1.0%
InternalInternal precisionprecision (2(2σσ) : 1.5%) : 1.5%
40 40 µµmm
20 20 µµmm
On single age determinations:
0.080
0.084
0.088
0.092
0.096
0.100
0.104
0.108
0.62 0.66 0.70 0.74 0.78 0.82 0.86 0.90
207Pb/235U
206 P
b/23
8 U
500
540
580
620
Zircon GRMTIMS: 577 ± 8 Ma
583 ± 9 (2583 ± 9 (2σσ) Ma) Ma
20 µm
360
340
320
300
280
260
240
2200.034
0.038
0.042
0.046
0.050
0.054
0.058data-point error ellipses are 2
Zircon 02123TIMS 295 MA
20 µm
296 ±1 (2σ) Ma
Pb
/23
8U
20
6
0.24 0.28 0.32 0.36 0.40 0.44207Pb/235U
40 µm
529 ± 16 Ma
716 ± 18 Ma
Zircons with inherited components Zircons with inherited components Internal Internal LigurideLiguride ophiolites ophiolites (Northern Apennine, Italy)(Northern Apennine, Italy)
340
300
260
220
180
140
100
60
20
data-point error ellipses are 2σ
Mean age 156 ± 4 Ma
0.06
0.05
0.04
Pb
/238 U
0.03
206
0.02
0.01
AntampombatoAntampombato--AmbatovyAmbatovy intrusion intrusion (Madagascar(Madagascar)
0.000.0 0.1 0.2 0.3 0.4
) 207Pb/235U
10000
120 110 100 90 80
to common Pb
Intercept age at 89 ±6 Ma
0.28
10000.24
1000.20
0.001
0.01
0.1
1
10
Rb Ba Nb Ta La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
zirc
on/C
1
20
6 Pb
0.16
0.00
0.04
0.08
0.12
20
7 Pb
/
50 60 70 80 90
238U/206Pb
MonaziteMonazite –– 193193 ArF ExcimerArF Excimer laserlaser5 5 µµm spot m spot sizesize
0.077
0.079
0.081
0.083
0.085
0.087
0.089
0.59 0.61 0.63 0.65 0.67 0.69 0.71207Pb/235U
206P
b/23
8U
Concordia Age 514.2 ±3.8 Ma
(95% conf.)
data-point error ellipses are 2σ
480
500
520
540
Mean 208Pb/232Th age532.8 ± 4.0
[0.76%] 95% conf.
208Pb/232Th ages
TIMS Age on zircons: 540 Ma
600
580
560
540
520
500
480
MULTI COLLECTOR MULTI COLLECTOR (MC)(MC)--ICPMSICPMS
11B/10B ratiosδ11B‰=[(11B/10B)sample/(11B/10B)SRM951)-1]X1000)
Major impediments in measuring δ11B with Laser ablation MC-ICP-MS:
•ICP-MS– Low sensitivity for light masses– Faraday detectors require several hundreds ppm
B in the sample for a precise 11B/10B determination under laser ablation
•B concentration– With the exception of a few minerals (e.g.
tourmaline), B abundance is usually below 100ppm and even below 1 ppm in mantle environments.
•Availability of standards
The LAThe LA--MCMC--ICPICP--MS instrument MS instrument • Laser ablation system
– Commercial UP213 from NewWave working at 213 nm.– The laser was operated in single spot mode with a repetition rate
of 10 Hz and a spot size from 60 to 80 µm in diameter.
• MC-ICP-MS– The Finnigan Neptune (Thermo), – Equipped with both multiple ion counters and Faraday cups.
0
10000
20000
30000
40000
50000
60000
10.545 10.550 10.555 10.560 10.565 10.570
Mass
bo
th t
rac
es
no
rma
lise
d t
o 11
B (
cp
s) 11B
10B
DetectorDetectorConfigurationConfiguration
1111B/B/1010B acquisitionB acquisition
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
0 10 20 30 40 50 60 70 80 90 100
cycle
Raw
11B
/10B
Faraday
Ion counters
NIST SRM 610B = 350 ppm
Isotope FractionationIsotope Fractionation1.1. Instrumental Mass bias Instrumental Mass bias
(13(13--14%)14%)
2.2. Laser induced fractionationLaser induced fractionation
3.3. Drift of detector (MIC)Drift of detector (MIC)
Isotope fractionation
B4 Tourmaline
-0.0015%
-0.0010%
-0.0005%
0.0000%
0.0005%
0.0010%
0.0015%
0.0020%
0 1 2 3 4 5 6 7
11B
/10B
fra
ctio
nat
ion
s-1
NIST SRM 610 4.60
4.39
y = -0.0030x + 4.5499
y = -0.0033x + 4.3439
Day1
Day2
MIC calibration
y = -0.0035x + 4.3451
y = -0.0032x + 4.3715
GOR132-G
NIST SRM 610
4.55
4.374.50
4.454.35
4.10
4.15
4.20
4.25
4.30
4.35
4.40
1 4 7 10 13 16 19 22 25 28 31 34 3analysis #
7 40 43 46 49 52 55 58 61 64
raw
11B
/10B
4.27
4.29
4.31
4.3311
B/10
B r
aw
1 2 3 4 5 6 7 8 9 10 11 12 1
analysis #3 14 15 18 19 20 21
Analytical MethodAnalytical MethodCorrection of:Mass bias – laser induced isotopic fractionation – ion counter drift
accepted
NIST61010
11
measured2
NIST61010
11measured1
NIST61010
11
measured
unknown10
11corrected
unknown10
11
BB
12
BB
BB
BB
BB
×+
=
standard sample standard sample standard
External standard Nist 610 – 11B/10B = 4.0490 (le Roux et al., 2004)
FaradayFaraday –– B4 tourmaline and B4 tourmaline and NistNist 610610Sample 11B/10Bmeas sd r.s.d.Nist610 4.6833 0.0027 0.058%B4 4.6268 0.0001 0.003%Nist610 4.6662 0.0025 0.053%B4 4.6276 0.0002 0.005%Nist610 4.6631 0.0022 0.048%B4 4.6269 0.0001 0.002%Nist610 4.6627 0.0024 0.052%B4 4.6272 0.0001 0.002%Nist610 4.6657 0.0021 0.046%B4 4.6274 0.0001 0.003%Nist610 4.6669 0.0025 0.053%B4 4.6270 0.0001 0.002%Nist610 4.6551 0.0020 0.043%
AveragesB4 4.6272 0.00031 0.007%Nist610 4.6649 0.00191 0.041%
B4 = 31400 ppm BNist610 = 350 ppm B
δ11B = 8.41 ± 0.34‰
Multi Multi IonIon CountersCounters –– StHs6/80StHs6/80Sample 11B/10Bmeas sd r.s.d.Nist610 4.3839 0.0051 0.12%StHs 4.3491 0.0096 0.22%Nist610 4.3638 0.0052 0.12%StHs 4.3430 0.0088 0.20%Nist610 4.3608 0.0038 0.09%StHs 4.3312 0.0109 0.25%Nist610 4.3523 0.0060 0.14%StHs 4.3434 0.0116 0.27%Nist610 4.3543 0.0046 0.11%StHs 4.3399 0.0094 0.22%Nist610 4.3542 0.0048 0.11%StHs 4.3054 0.0119 0.28%Nist610 4.3399 0.0066 0.15%StHs 4.3250 0.0103 0.24%Nist610 4.3332 0.0052 0.12%StHs 4.3159 0.0096 0.22%Nist610 4.3237 0.0050 0.11%StHs 4.3230 0.0084 0.20%Nist610 4.3389 0.0044 0.10%
StHs6/80= 12 ppm BNist 610 = 350 ppm B
δ11B = -4.3 ± 2.4‰
Summary of resultsSummary of results
-15
-10
-5
0
5
10
15
-15 -5 5 15δ11B (‰) measured
δ11B
(‰
)re
fere
nce
B4 (tourmaline)B = 31400 ppm
StHs6/80 (glass)B = 11 ppm
GOR128-G (glass)B = 23 ppm
GOR132-G (glass)B = 18 ppm
error bars are 2σ
Results on Mt. Etna ashesResults on Mt. Etna ashes
Spot size 60 µmNist 610 external standard
Average δ11B = -8.0 ± 1.9 ‰
May October December
Other possible applicationsOther possible applications
• High precision U-Pb zircon dating• Li, Hf, Pb, Sr isotopes on geological samples
Provided that suitable standards for in-situ analyses are available
ConclusionsConclusionsLaser Ablation microprobeLaser Ablation microprobe
(266/213/193 nm)(266/213/193 nm)
MCMC--ICPMSICPMS
(LA)
HRHR--ICPMSICPMSMulti element(ppb level LOD)
&low precision isotope
determinations(Pb-geochronology)
Ion counters(ppm level determinations) (100s ppm determinations)
Faraday
High precision isotope determinations