The document discusses the benefits of ICP-MS/MS technology for challenging clinical trace element analysis applications. ICP-MS/MS can overcome limitations of single quadrupole ICP-MS by removing interferences through reaction cell modes. Examples show it can achieve lower detection limits than ICP-QMS for applications like measuring titanium in serum and urine, selenium in the presence of gadolinium, and manganese in whole blood. The document concludes ICP-MS/MS is suitable for applications where collision cell modes are insufficient and provides capabilities for addressing abundance sensitivity issues at lower cost than other high-end techniques.

1. Benefits of ICP-qqq-MS
in MS/MS mode for
challenging clinical
trace element
applications
Transforming ICP-MS
Technology
Dr Raimund Wahlen
Agilent Technologies
raimund_wahlen@agilent.com
07920 -466 161
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October 15, 2013

2. Presentation Overview
• Addressing interferences in ICP-MS – collision mode
• Reaction mode in quadrupole ICP-QMS
• Benefits of ICP-qqq-MS or MS/MS mode
• Examples of clinical applications:
•
Trace Ti in serum + urine
•
Se in presence of Gd – MRI patients
•
Mn in whole blood
• Conclusions
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October 15, 2013

3. Some Common Polyatomic Spectral Interferences
for Analysis of Clinical Samples by ICP-MS
Ion
51V+
52Cr+
59Co+
60Ni+
63Cu+
66Zn+
75As+
78Se+
80Se+
95Mo+
98Mo+
103Rh+
111Cd+
Interfering ion
35Cl16O+
40Ar12C+
43Ca16O+
44Ca16O+
40Ar23Na+
32S16O18O
40Ar35Cl+
38Ar40Ar+
40Ar40Ar+
79Br16O+
81Br16O1H+
40Ar63Cu+
95Mo16O+
In addition you can get isobaric interferences (eg 40Ar+ on 40Ca+) and doublycharged interferences (eg 160Gd++ on 80Se) on target isotopes

4. Principle of Helium Collision Mode and Kinetic Energy
Discrimination (KED)
Polyatomic
ions
Analyte
ions
Energy distribution
of analyte and
interfering
polyatomic ions
with the same
mass
Polyatomic
ions
Analyte
ions
Energy
At cell entrance,
analyte and
polyatomic ion
energies overlap.
Energy spread of both
groups of ions is
narrow, due to
ShieldTorch System
Page 4
Bias voltage
rejects low energy
(polyatomic) ions
Energy
Energy loss from each
collision with a He
atom is the same for
analyte and polyatomic
ion, but polyatomics
are bigger and so
Cell collide more often
Entrance
Cell
Exit
By cell exit, ion energies
no longer overlap;
polyatomics are rejected
using a bias voltage
“step”. Analyte ions
have enough residual
energy to get over step;
polyatomics don’t
(energy discrimination)

5. Efficient interference removal in He mode
 He collision mode is well-accepted for accurate multi-element analysis of unknown,
variable and high-matrix samples (enviro, food, clinical, pharma…)
 He mode on 7700 is effective for polyatomic interferences at low- and sub-ppb levels
7700 - He mode for Polyatomic Interferences
No gas mode (left) and He mode (below)
Complex matrix in no gas (above) and
He mode (right, with 10ppb std inset)
7700 removes ALL polyatomics
 All elements in routine clinical matrices can be measured with a single set of
instrument parameters
 Easy set-up, fast validation, reliable results
 But … limitations for isobaric or doubly-charged interferences (e.g. Gd++)
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October 15, 2013

6. How Reaction Mode Works in ICP-QMS
1. On-Mass Measurement: Unreactive analyte does not react with
chosen cell gas, remains at original m/z and so can be separated from
reactive interferences
Reaction
gas
On-mass
interference
Analyte
Analyte and
interfering ions
enter reaction
cell
Reaction
product ion
Analyte
Interferenc
e M+ 
MR+
Interference
reacts to form
product ion
Quad set to original
analyte mass – rejects
interference product
ion(s)
Reactive interferences are converted to product ions at a new mass – can
be rejected by analyzer quad, which is set to original analyte mass
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October 15, 2013

7. How Reaction Mode Works in ICP-QMS
2. Mass-Shift Measurement: Reactive analyte reacts with chosen cell
gas, is moved to a new product ion mass and can be separated from
unreactive interferences
Reaction
gas
Original
interfering
ion
On-mass
interference
Analyte
Analyte
product ion
Analyte
M+  MR+
Analyte and
interfering ions
enter reaction
cell
Analyte reacts
to form product
ion
Quad set to analyte
product ion mass –
rejects original
interfering ions
Reactive analyte is converted to product ions at a new mass –
interferences remain at original mass and are rejected by analyzer quad
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October 15, 2013

8. Limitations of Reaction Mode in ICP-QMS
 Limitations of reactive cell gases in quadrupole ICP-MS are welldocumented:
 All ions enter the cell, affecting reaction processes and product ions formed.
Gives variable results when sample type/matrix or co-existing analytes change
 Product ions from matrix or other elements can create new overlaps on analytes
 Analyte product ions can be overlapped by other analytes/matrix elements
 Can tandem MS configuration (ICP-MS/MS) address the variability
caused by co-existing elements and changing matrix components?
Agilent 8800 ICP-MS/MS matches 7700
performance in He mode, but biggest
benefit should be controlled and consistent
MS/MS operation in reaction mode.
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October 15, 2013

9. New 8800 ICP Triple Quad MS – unique capabilities
High matrix
introduction
(HMI)
technology
Dual conical Extraction and
Omega lens focuses ions
across the mass range
First quad Q1: High frequency
hyperbolic quadrupole mass filter –
selects ions that enter the cell
Low flow
sample
introduction
system
9 orders
dynamic range
electron
multiplier (EM)
detector
Peltiercooled
spray
chamber
Fast, frequencymatching 27MHz
RF generator
9
3rd generation collision/
reaction cell (ORS3)
with 4 cell gas lines
Analyzer quad Q2:
High frequency
hyperbolic quadrupole
– selects ions that
pass to detector
Robust, high-temperature
plasma ion source
High-transmission,
matrix tolerant interface
Efficient twin-turbo
vacuum system
October 15, 2013

10. How Reaction Mode Works in ICP-MS/MS
1. On-Mass Measurement: Unreactive analyte does not react with
chosen cell gas, remains at original m/z and so can be separated from
reactive interferences. No new cell-formed interferences can occur at
the analyte mass, since all non-target masses are rejected by Q1
Reaction
gas
On-mass
interference
Analyte
Off-mass
interference
Reaction
product ion
Analyte
All non-target
masses
Q1 set to analyte
mass – rejects
all non-target
masses
Interferenc
e M+ 
MR+
Interference
reacts to form
product ion
Q2 set to original
analyte mass – rejects
any off-mass product
ion(s)
With ICP-MS/MS, Q1 rejects all non-target masses, ensuring no new
analyte/matrix product ions can form new overlaps on original analyte mass
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October 15, 2013

11. How Reaction Mode Works in ICP-MS/MS
2. Mass-Shift Measurement: Reactive analyte reacts with chosen cell
gas, is moved to a new product ion mass and can be separated from
unreactive interferences. No existing ions can overlap new analyte
product ion, as all non-target masses are rejected by Q1
Reaction
gas
On-mass
interference
Analyte
Off-mass
interference
Original
interfering
ion
Analyte
product ion
All non-target
masses
Q1 set to analyte
mass – rejects
all non-target
masses
Analyte
M+  MR+
Analyte reacts
to form product
ion
Q2 set to analyte
product ion mass –
rejects original
interfering ions
With ICP-MS/MS, Q1 rejects all non-target masses, ensuring no existing
ions (analyte, matrix, or polyatomic) can overlap new analyte product ion
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October 15, 2013

12. MS/MS Product Ion Scan - Titanium
Ammonia gas
introduced into
the cell
TiNH2(NH3)4
TiNH(NH3)4
Ti(NH3)5
Ti(NH3)6
Peaks corresponding to TiNH2(NH3)4 and Ti(NH3)6 selected for
NeutralTiNH(NH3Scans
Gain )3
TiNH2(NH3)3
TiNH2(NH3)5
Ti(NH3)4
“Ti”
TiNH(NH3)5
TiNH
TiNH(NH3) TiNH(NH3)2
Resulting spectrum might look complicated but all peaks are
only from m/ƶ 48 single transitions can be selected…
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Q1 set to m/ƶ 48
Q2 scans
spectrum
Spectrum
displays all
resulting ions
from m/ƶ 48
ONLY
Confidentiality Label
October 15, 2013

13. MS/MS Neutral Gain Scan – Titanium with
Ammonia Adducts at Two Mass Transitions
Q2
Q1 setset to Q1 +84amum/ƶ 46, 47, ]48, 49, 50[Ti(NH3)6]
to let in only [TiNH2(NH3)4 & +102amu INDIVIDUALLY
Q2 set to transition masses:
Q1 +84amu [TiNH2(NH3)4]
Serum and Urine Check
Q1 +102amu [Ti(NH3)6]
Based upon results from this HNO3 standard the system was run using basic
preparation for clinical samples (dilution into NH4OH, EDTA, Triton-X, BuOH)
Therefore transitions used:
• Standards  130
46 were prepared in the basic 148 medium
46 preparation
• Standard addition NOT used
47  131
47  149
• Both diluted serum and urine (10x) run within same batch against same
48
48  150
calibration  132
• Data compared to no cell gas and49 gas modes
other 151
49  133
50  134
50  152
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Confidentiality Label
October 15, 2013

14. Ti in clinical matrices
Target
47 -> 131 Ti [ NH3 ]
Sample Name
Conc. [ ug/l ]
Urine Blank
4.6 (2.2-7.0)
2.80
Urine Blank
4.6 (2.2-7.0)
3.50
Urine Trace Elements
14.81
Urine Trace Elements
14.99
Serum L1
1.28 (0.86-1.80)
1.21
Serum L1
1.28 (0.86-1.80)
1.27
Serum L2
1.76
Serum L2
1.82
48 -> 132 Ti [ NH3 ]
Conc. [ ug/l ]
2.79
2.93
15.27
15.49
1.15
1.18
1.92
1.64
49 -> 133 Ti [ NH3 ] 50 -> 134 Ti [ NH3 ]
Conc. [ ug/l ]
Conc. [ ug/l ]
2.92
2.49
3.33
2.66
14.42
15.13
15.50
15.05
1.14
0.80
1.09
0.89
1.61
1.13
1.76
1.22

15. Multiple calibrations for qualifier isotopes

16. Se by ICP-MS/MS Mass-Shift with O2 Cell Gas
Same reaction with O2 cell gas is also used for Se on 8800 ICP-MS/MS:
80Se+ + O <cell gas>  96SeO+
2
40Ar +, Gd++, Dy++ + O  no reaction
2
2
BUT Q1 of 8800 rejects other ions that would overlap SeO+ at mass 96
Reaction
gas (O2)
40Ar40Ar+
160Gd++,160Dy++
40Ar40Ar+
160Gd++, 160Dy++
80Se16O+
80Se+
96Zr+, 96Mo+,
96Ru+
96Zr+,
80Se+  80Se16O+
96Mo+, 96Ru+
Q1 (m/z 80) – rejects all
ions apart from m/z 80
Q2 (m/z 96) – rejects all
ions apart from m/z 96
Allows measurement of SeO+ at product ion mass, after removal of original
Ar2+/REE++ interference, and existing ions at SeO+ product ion mass.
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October 15, 2013

17. Gd++ Interference on Selenium
• Gd is used as a contrast agent for MRI. Concentration in
patient can be as high as 1ppm (sometimes even higher)
• This causes problems with obtaining accurate Se
measurements for those patients
• MS/MS and O2 cell gas effectively avoids the Gd++ bias in the
data, giving consistent recovery for Se (target 89ng/mL)
Serum + Gd 250 ppb
Serum + Gd 500 ppb
Serum + Gd 1000 ppb
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No Gas
99.87
112.12
121.07
Optimized O2
91.38
91.70
91.78
October 15, 2013

18. 8800 Abundance Sensitivity in Single-Quad Mode
Trace 55Mn is overlapped by 56Fe in 1000ppm Fe
Abundance Sensitivity (AS) is
the degree of peak “tailing” – the
contribution a peak makes to the
adjacent (-1 and +1amu) masses
7700 specification is 5 x 10-7 on the
low mass side
Note: log intensity scale
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October 15, 2013

19. Other Sample Types – Manganese in Whole Blood
Mn is difficult to measure by ICPQMS at natural (sub-ppb) levels in
whole blood, due to “tail” of 56Fe
(and 54Fe) peak across 55Mn
8800 MS/MS ensures 55Mn is
completely separated from 54/56Fe
Overlaid spectra show blank whole
blood (10x dil) & 500ppt Mn spike
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October 15, 2013

20. Conclusions
•
Efficient He KED mode suitable for many routine clinical labs
–
•
MS/MS reaction cell modes can overcome situations where KED mode is
not sufficient:
–
–
•
•
8800 can be used in He SQ mode for these elements
Lower LOD requirements (similar to HR-ICP-MS)
Multiple spectral interferences other than polyatomics on same isotope
Unique capabilities for addressing abundance sensitivity issues
Ease of use is similar to 7700 single-quad ICP-MS
• Same MassHunter software
• Many of the same hardware components
•
Capital and running costs significantly lower than other high-end
techniques such as SF-ICP-MS
•
ICP-qqq-MS already established in many leading R+D labs, and one
system soon to be installed in NHS lab
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October 15, 2013

21. Thank You for your attention
Questions?
Agilent 8800 QQQ
ICP-MS
Agilent AAS
Agilent MP-AES
Agilent ICP-OES
Agilent 7700 ICP-MS
The Market Leader in Atomic Spectroscopy
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