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RIGHT SOLUTIONS · RIGHT PARTNER
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RIGHT SOLUTIONS · RIGHT PARTNER
Determination of trace and ultra-trace elements by ICP-SFMS
Ilia Rodushkin, Emma Engström, Douglas Baxter
ALS Scandinavia AB
Luleå University of Technology
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Luleå laboratory
Part of ALS group (>300 laboratories
worldwide)
Focus areas: ultra-trace multi-elemental
determinations and isotope ratio
measurements
>130 000 samples annually
Close co-operation with LTU resulting
in 200 publications
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3 ICP-OES
14 ICP-SFMS
3 AFS
1 ICP-QMS
2 MC-ICP-MS
Instrumentation
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High ion transmission = high sensitivity
Can be operated in high resolution mode(s)
Flat-top peaks in low resolution
Instrumental dark current <0.2 cps
Flexible introduction system
Relatively low matrix tolerance
Large and heavy
Expensive
Requires experienced operators
ICP-SectorFieldMS = HighResolution-ICP-MS = Double Focusing ICP-MS
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Before MS
Sample collection
Homogenization – representative sub-sample, contamination
Digestion – recovery from matrix, (co)precipitation and volatile losses,
contamination
Column separation – purification efficiency, yield, contamination
Evaporation/re-dissolution – recovery, contamination
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The UltraCLAVE Principle
The patented* Milestone UltraCLAVE
achieves extraordinary performance
capabilities by combining direct
microwave heating in a high pressure
reactor, which acts simultaneously as
microwave cavity and vessel.
The next generation MW system
The Milestone UltraCLAVE
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What a difference a droplet (10 µl) HF makes…
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What a difference a droplet (10 µl) of HF makes…
3600 →
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Sensitivity
Matrix tolerance
Spectral interferences
Instrumental background
Analyte blank
Accurate measurement - factors to consider
Measured signal
Signal from analyte
presented in sample
Unwanted contributions
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Sensitivity – upper limit
• Analyte – 239
Pu
• Sample uptake – 0.2 ml/min
• Transport efficiency – 100%
• Law of conservation of mass is still valid
Highest possible sensitivity for 1 pg l-1
8400 counts s-1
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Cell ICP-QMS: 0.1-2
ICP-SFMS, standard set-up: 2
ICP-SFMS, X skimmer, CH4: 5-8
ICP-SFMS, X skimmer, Aridus + N2: 20-30
MC-ICP-MS, Jet interface, APEX: 110-140
’Record’ transport efficiency of ICP-MS is under 2%
Sensitivity in LRM, counts s-1 per 1 pg l-1 238U
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High efficiency nebulizers – Aridus II and Apex HF
Intensity gain by efficient utilization of sample
solution
’Dry’ plasma – much lower O, H and OH
interferences
Great signal stability for low-matrix solutions
Losses of volatile elements (Hg, Se, As, Os, B)
Low matrix tolerance
Long memory
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Sensitivity in LRM, counts s-1 per 1 pg l-1
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BEC, ppq LOD, ppq LOQ, ppq Major interferences
226Ra 0.11 0.18 0.59 WAr, ReArH, PbOH2, BaSr, BaCaCa
230Th 0.09 0.14 0.45 Th, U tails, OsAr, PtO2, HgO2, IrCl, PtCl
232Th 44 11 36 OsAr, HgO2, AuCl, PtCl
234U 0.07 0.14 0.48 ThH2, Th, U tails, PtAr, AuCl, PtCl
235U 0.22 0.53 1.8 U tail, PtAr, HgCl, PtCl, HgO2
236U 0.07 0.17 0.56 UH, U tail, PtAr, HgCl, HgO2
237Np 0.09 0.15 0.51 U tail, UH2, AuAr, HgCl, HgO2
238U 30 7 23 PtAr, HgAr, HgCl, TlCl, PbO2
239Pu 0.03 0.08 0.25 UH, U tail, HgAr, HgCl, PbCl, PbO2
240Pu 0.03 0.06 0.21 UH2, U tail, HgAr, TlCl, PbO2
241Am 0.05 0.06 0.20 U tail, HgAr, HgCl, PbCl, BiO2
242Pu 0.03 0.05 0.16 U tail, HgAr, TlCl, PbCl
243Am 0.06 0.06 0.19 TlAr, PbCl
Summary of BEC, limits and interferences
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BEC, ppq LOD, ppq LOQ, ppq Major interferences
226Ra 0.11 0.18 0.59 WAr, ReArH, PbOH2, BaSr, BaCaCa
230Th 0.09 0.14 0.45 Th, U tails, OsAr, PtO2, HgO2, IrCl, PtCl
232Th 44 11 36 OsAr, HgO2, AuCl, PtCl
234U 0.07 0.14 0.48 ThH2, Th, U tails, PtAr, AuCl, PtCl
235U 0.22 0.53 1.8 U tail, PtAr, HgCl, PtCl, HgO2
236U 0.07 0.17 0.56 UH, U tail, PtAr, HgCl, HgO2
237Np 0.09 0.15 0.51 U tail, UH2, AuAr, HgCl, HgO2
238U 30 7 23 PtAr, HgAr, HgCl, TlCl, PbO2
239Pu 0.03 0.08 0.25 UH, U tail, HgAr, HgCl, PbCl, PbO2
240Pu 0.03 0.06 0.21 UH2, U tail, HgAr, TlCl, PbO2
241Am 0.05 0.06 0.20 U tail, HgAr, HgCl, PbCl, BiO2
242Pu 0.03 0.05 0.16 U tail, HgAr, TlCl, PbCl
243Am 0.06 0.06 0.19 TlAr, PbCl
Summary of BEC, limits and interferences
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1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
218
220
222
224
226
228
230
232
234
236
238
240
m/z
Inte
nsit
y, co
un
ts s
-1
Tailing
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Standard Aridus II Aridus II+RPQ*
Th
-2 amu 1.5*10-6 1.2*10-6 0.4*10-6
-1 amu 4*10-6 2*10-6 0.8*10-6
+1 amu 65*10-6 16*10-6 5*10-6
+2 amu 10*10-6 2*10-6 0.7*10-6
U
-2 amu 1.7*10-6 1.4*10-6 0.4*10-6
-1 amu 4*10-6 2*10-6 0.8*10-6
+1 amu 72*10-6 17*10-6 5*10-6
+2 amu 11*10-6 2*10-6 0.8*10-6
Retarding Potential Quadrupole lense adjusted to provide >80% of original sensitivity
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Matrix separation/preconcentration
20-200 times improvement compared to direct
analysis after dilution
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Memory effects (self aspiration, Aridus II)
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Memory effects (self aspiration, Aridus II)
Blanks (1.4 M HO3) 50 ng L-1 239Pu, 242Pu STDs Blanks with HF
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In tubing – min. length and strong rinse solutions
In spray chamber – low-volume or DIN, matrix optimization
(suppression of volatile species formation)
On cones – use ’Si-trick’
Inside MS – wait…
Memory effects
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Why Luleå?
October January April
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Ag
Pt/Au
Sn
Si
Torch and interface may release
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Personnel issues
Spot the common denominator?
Stibnite
Antimonite
Sb2S3
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• Al, Cl, Zr, Hf, Si
Aluminium Chlorohydrate, Aluminium
Zirconium Tetrachlorohydrex Gly,
Silica, Silica Dimethyl Silyate, Hf
Deodorants
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Faster and more convenient way
to handle relatively large sample
volumes (>5 ml)
Contaminates sample with Pt
and Ir at ppt level, Pd and Au at
ppq level because of Pt-Ir valve
spring
’Metall-free’ dispenser
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Au
0,0
0,2
0,4
0,6
0,8
1,0
1,2
Road Domestic Laboratory 1 Laboratory 2
Co
ncen
trati
on
, µ
g g
-1
Concentrations of ‘rare’ elements are enriched in laboratory dust
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Dedicated areas for ultra-trace preparations
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All labware in contact with samples is acid cleaned
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Applications dictate choice of tube materials
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ICP-SFMS offers instrumental LODs in sub-ppq range
Ultimate technique for multi-element determination
in variety of matrices
232
Th, 235
U, 238
U can be accurately measured almost
in any matrices
Analysis at endogenous levels of 226
Ra, 230
Th, Pu, Am
will require matrix separation/pre-concentration and
optimized introduction systems
Conclusions
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Thank you for your attention!
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206Pb
++
87Rb
16O
+,
87Sr
16O
+, 86
Sr16
OH+
63Cu
40Ar
+, 65
Cu36
Ar+, 67
Zn36
Ar+
23Na
40Ar
40Ar
+,
23Na
40Ar
40Ca
+,
23Na
40Ca
40Ca
+
66Zn
37Cl
+,
68Zn
35Cl
+
32S
34S
37Cl
+, 33S
33S
37Cl
+, 34S
34S
35Cl
+, 34
S34
S34
SH+
96Mo
7Li
+, 97
Mo6Li
+, 40
Ar35
Cl12
C16
O+
Spectral interferences on 103Rh
The majority of spectral interferences can be eliminated using high resolution capabilities of ICP-SFMS
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Interferences
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Why Luleå?
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Determination of TCEs in environmental matrices
Ga, Ge, In, Nb, Ta, Te, Tl Ir, Os, Pd, Pt, Rh
Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Y, Yb
Quantitate recovery at preparation stages
Preventing losses during analysis
Optimization of instrumental conditions (low oxides)
Right resolution settings
Matrix separation if necessary
Analyte specific introduction (Os, Ge)