SHORT COURSE
ICP – MASS SPECTROMETRY
INSTRUMENTATION
Frank Vanhaecke
Ghent University, Belgium
WHERE EXACTLY IS BELGIUM?
 Facts
► Area: 30,528 km²
► Population ~ 11,000,000
► Inhabitation density: 360 /km2
► Capital: Brussels
• European Parliament
• NATO headquarters
► Northern part: Flanders (Dutch)
► Southern part: Wallonia (French)
WHERE SHOULD I KNOW BELGIUM FROM?
PERHAPS … WHO KNOWS?
Leo Baekeland?
Chemist, inventor
“Father of plastics”
Bakelite
phenol-formaldehyde resin
Christian de Duve?
Biochemist
Nobel Prize for Medicine in 1974
Discovered lysosomes and peroxisomes
as cell organelles
PERHAPS … WHO KNOWS?
Eddy Merckx ?
1960-70s,
5 times winner of Tour de France
World Champion
World hour record holder
“The cannibal”
Kim Clijsters ?
Recently “retired”
3 times US open, 1 time Australian open
Achieved nr. 1 world ranking
PERHAPS … WHO KNOWS?
Tintin The smurfs
WHERE SHOULD YOU KNOW BELGIUM FROM?
Trappist beers – alcohol content: 6 – 12%
WHERE SHOULD YOU KNOW BELGIUM FROM?
WHAT ABOUT GHENT?
 Wikipedia?
► Ghent started as a settlement at the confluence of the Rivers Scheldt
and Lys and became in the Middle Ages one of the largest and
richest cities of northern Europe. Today it is a busy city with a port
and a university.
THE MIDDLE AGES IN GHENT
GRAVENSTEEN CASTLE (1180)
THE MIDDLE AGES IN GHENT
FRIDAY’S MARKET SINCE 1199 !
THE MIDDLE AGES IN GHENT
GRASLEI – MEDIAEVAL PORT
THE MIDDLE AGES IN GHENT
THE BELFRY & GOTHIC CHURCHES
GHENT UNIVERSITY
°1817 - ~38,000 STUDENTS & ~7,000 STAFF MEMBERS
DEPARTMENT OF ANALYTICAL CHEMISTRY
ATOMIC & MASS SPECTROMETRY RESEARCH GROUP
A&MS
INDUCTIVELY COUPLED PLASMA – MASS SPECTROMETRY
ICP-MS
 What is ICP-MS?
► Wikipedia?
• Inductively coupled plasma mass spectrometry (ICP-MS) is a type of
mass spectrometry which is capable of detecting metals and several
non-metals at concentrations as low as one part in 1012 (part per trillion).
This is achieved by ionizing the sample with inductively coupled plasma
and then using a mass spectrometer to separate and quantify those ions.
• Compared to atomic absorption techniques, ICP-MS has greater speed,
precision, and sensitivity. However, analysis by ICP-MS is also more
susceptible to trace contaminants from glassware and reagents. In
addition, the presence of some ions can interfere with the detection of
other ions.
► A powerful technique for the determination of (ultra)trace elements
ICP – MASS SPECTROMETRY
 ° 1983, at present: thousands of instruments in use
 Research tool more robust & well-established technique
 Advantages
► Low limits of detection
► Multi-element capabilities
► Wide linear dynamic range
► High sample throughput
► Relatively simple spectra
► Ability to obtain isotopic information
► Ease of combination with
• Alternative sample introduction systems
• Chromatographic separation techniques
MASS SPECTROMETRY
Ion source MS Data handlingDetector
High vacuum region
THE INDUCTIVELY COUPLED PLASMA
ICP
INDUCTIVELY COUPLED PLASMA – ICP
PLASMA =
GAS MIXTURE AT HIGH TEMPERATURE, CONTAINING
MOLECULES, ATOMS, IONS AND ELECTRONS
 Presence of charged particles
► Energy supply via induction
PLASMA TORCH & ICP
rf coil
quartz torch
ICP (Tion : 7500 K)
cool
gas
auxiliary
gas
carrier gas
+
sample aerosol
FORMATION OF ICP & ANALYTE IONIZATION
Rf frequency: 27.12 or 40.68 MHz
Quartz-controlled oscillator (27.12)
Free running generator (27.12 or 40.68)
rf current through Cu coil
time-dependent magnetic field
electrons accelerated in circular paths
collision with Ar atoms: ionization
seed electrons: spark (Tesla-generator)
analyte ionization
electron impact M + e-  M+ + 2ePenning
ionization Ar* + M  M+ + Ar + e-
PROCESSES IN THE ICP
SAMPLE INTRODUCTION VIA NEBULIZATION
Residence time of analyte in ICP: ~ ms
IONIZATION EFFICIENCY OF THE ICP
Degree of ionization 
Ionization energy IE in eV
Saha equilibrium constant:
With Tion ~7500 K; ne ~ 1015 cm-3
Degree of ionization:















iona
i2
3
2
ione
a
ei
ion
kT
IE
exp
Z
Z2
h
kTπm2
n
nn
K
ione
ion
a
ei
e
a
ei
ia
i
Kn
K
n
nn
n
n
nn
nn
n







 






 



SAMPLE INTRODUCTION INTO THE ICP
 General
► Sample or representative part  ICP
► Convert sample into form transportable by Ar carrier gas
 Standard sample introduction system
► Pneumatic nebulizer + spray chamber
 Pneumatic nebulizer
► Conversion of sample solution into aerosol
 Spray chamber
► Removal of larger droplets
• Avoid plasma overloading
• Warrant efficient atomization & ionization in ICP
STANDARD SAMPLE INTRODUCTION SYSTEM
PNEUMATIC NEBULIZER & SPRAY CHAMBER
to ICP
primary aerosol
primary aerosol
sample
solution
to waste
1
2
LASER ABLATION
AS A MEANS OF SAMPLE INTRODUCTION
 Direct analysis of solid materials
► Conducting & non-conducting / Opaque & transparent
ION EXTRACTION FROM THE ICP
 Sampling cone & skimmer, central aperture ~1 mm
 Expansion chamber (1 mbar)  supersonic expansion of extracted gas
► Composition of plasma gas is ‘frozen’
 Central beam via skimmer aperture  lens system & MS
5
6
4
1
23
ICP: atmospheric pressure
to MS
10-5 - 10-9
mbar
ION EXTRACTION FROM THE ICP
ION EXTRACTION FROM THE ICP
Ar ICP
Tion ~7500 K, ne- ~1015 cm-3
Sampled via 2-cone interface
ION EXTRACTION FROM THE ICP
sampling cone
Mach disc
barrel
shock
zone
of
silence
skimmer
extraction lens (-)
material cone & skimmer ?
 thermal conductivity
 chemical inertness
 purchase price
Ni vs. Pt
LENS SYSTEM
 Set-up & complexity
► from a single lens to complicated set-ups ...
 Goals?
► Selection of positive ions
► Efficient transport to & introduction into mass analyser
SELECTION OF POSITIVE IONS IN THE LENS SYSTEM
Skimmer
Ion Lens
Components
Diffused electrons,
negative ions &
neutral components
Positively
charged ions
ION DETECTION
ION DETECTION
CONTINUOUS DYNODE ELECTRON MULTIPLIER
multiplication
effect
- 2000 V
avelanche of electrons
multiplication factor: 107 - 108
pulse counting mode vs. analog mode
ION DETECTION
DISCRETE DYNODE ELECTRON MULTIPLIER
ion
discrete dynodes at successively higher
potential
secondary
electron
avelanche
of
electrons
multiplication effectcathode
signal
multiplication factor: 107 - 108
pulse counting mode vs. analog mode
ION DETECTION / ELECTRON MULTIPLIER
 Comparison of detector signal with threshold value
► Background < 0.1 count / s
 Avoid photons reaching detector
► Photon stop in ion beam
► Detector mounted off-axis
► Ion lens system, quadrupole filter & detector off axis
• Omega-lens (Agilent)
 Limited life-time (= consumable)
► 1 - 2 years
 Detector dead time
► Handling of one ion, no possibility to detect another one
► More pronounced effects at higher count rates
► Accurate isotope ratio determination requires correction
PREVENTING PHOTONS FROM
REACHING THE DETECTOR
photons ions
WWWW
Photon stop
Omega lensOff-axis detector
photons
ions
ions
electrostatic lens system
EM
0 V
-2000 V
Various systems based on
influence of electrostatic
field on ion trajectory
skimmerMS
PREVENTING PHOTONS FROM
REACHING THE DETECTOR
Ion mirror
THE MASS SPECTROMETER
MASS ANALYSIS – THE QUADRUPOLE FILTER
ion
source detector
quadrupole filter
rf DC
source
mass/charge ratio
ion transmission efficiency
QUADRUPOLE-BASED ICP – MASS SPECTROMETRY
BASIC OPERATION PRINCIPLE OF QUADRUPOLE FILTER
 Quadrupole rods
► DC component
► AC (rf) component
 Instable path ?
► Magnitude actual negative
potential
► frequency of AC component
► Position of ion
► Velocity of ion
► Mass-to-charge ratio of ion
 Heavy ions
► Average (DC) potential
 Lighter ions
► Motion corrected by AC field
separate evaluation of effect of
each pair of quadrupole rods on ion paths
Electrode potential XZ vs. YZ
equal magnitude, different polarity
U + Vsin(t)
BASIC OPERATION PRINCIPLE OF QUADRUPOLE FILTER
 XZ-plane
► DC component : +
• Sufficiently heavy ions only undergo focusing effect (DC)
• Path of lighter ions affected by AC-field
High mass filter
BASIC OPERATION PRINCIPLE OF QUADRUPOLE FILTER
Low mass filter
 YZ-plane
► DC component : •
Sufficiently heavy ions only undergo defocusing effect (DC)
► Path of lighter ions affected by AC-field
BASIC OPERATION PRINCIPLE OF QUADRUPOLE FILTER
high mass filter low mass filter bandpass mass filter
+ =
+ =
 Advantages
► High scanning speed
► Can be used at relatively high pressures
► Instrumental simplicity & low purchase price
 Disadvantages
► Low mass resolution (R)
• Ions only separated if m  1/2 u
 Data acquisition modes
► Spectral scanning vs. peak hopping / peak jumping
BASIC OPERATION PRINCIPLE OF QUADRUPOLE FILTER
SPECTRAL INTERFERENCES IN
QUADRUPOLE-BASED ICP-MS
 Disadvantage of quadrupole filter
► Low mass resolution (R)
• Ions separated if m  1/2 u
• Otherwise: overlap of ion signals (spectral interferences)
 Overlap of signals of isobaric nuclides
► Not problematic
• For every element (except In): one isotope interference-free
 Polyatomic ions & doubly charged ions
► Spectral overlap of ions showing the same nominal m/z ratio
TYPES OF POLYATOMIC IONS IN ICP-MS
 Ar-containing ions
► Ar introduced in ICP at ~ 20 L/min
► Ar+ and Ar2
+
► Ar + elements from solvent, surrounding air and/or matrix
• ArO+, ArOH+, ArN+, ArC+, ArCl+, ArNa+, …
858075706560555045403530252015105
10 0
10 1
10 2
10 3
10
4
10
5
10
6
10
7
10 8
10 9
10 10
Mass
ionsignal/cps
O+
Ar+
ArH+
ArO+
Ar2
+
LOG !
ICP-MS BACKGROUND SPECTRUM
FOR HIGH-PURITY WATER
ICP-MS BACKGROUND SPECTRUM
FOR HIGH-PURITY WATER
TYPES OF POLYATOMIC IONS IN ICP-MS
 Ar-containing ions
► Ar introduced in ICP at ~ 20 L/min
► Ar+ and Ar2
+
► Ar + elements from solvent, surrounding air and/or matrix
• ArO+, ArOH+, ArN+, ArC+, ArCl+, ArNa+, …
 Oxide & hydroxide ions
► MO+ (m/z + 16) and MOH+ (m/z + 17)
► MO+/M+ determined by M-O bond strength
► Usually MO+/M+ > MOH+/M+
► Optimization of instrument settings MO+/M+  0.05 (5%)
► Still problematic if m/z(M1O+) = m/z(M2
+) and c(M1) >> c(M2)
► Formed in ICP : low t° in neighbourhood of vaporizing droplets
 Other molecular ions
► SO2
+, SO2H+, SiCl+, ...
DOUBLY-CHARGED IONS IN ICP-MS
 Doubly charged ions
► M2+ (m/z ÷ 2)
► M2+/M+ determined by (IP2 – IP1)
► Optimization of instrument settings M2+/M+  0.05 (5%)
► Still problematic if m/z(M1
2+) = m/z(M2
+) and c(M1) >> c(M2)
► if m/z of M1 = uneven  M1
2+ is no problem
• M1
2+ signal at non-integral m/z
• Quadrupole filter shows sufficient resolution
► Formed in ICP
SOME IMPORTANT SPECTRAL INTERFERENCES
DUE TO THE PRESENCE OF CHLORINE
SOME IMPORTANT SPECTRAL INTERFERENCES
DUE TO THE PRESENCE OF CARBON
…
SOME IMPORTANT SPECTRAL INTERFERENCES
DUE TO THE PRESENCE OF SULPHUR
…
SOME IMPORTANT SPECTRAL INTERFERENCES
DUE TO THE PRESENCE OF PHOSPHORUS
…
SPECTRAL INTERFERENCES IN ICP-MS
COLLISION/REACTION CELLS
 Multipole assembly with (2n + 2) rods:
► Quadrupole
► Hexapole
► Octopole
Hexapole cell
Thermo Scientific
Xseries II
Octopole cell
Agilent Technologies
Quadrupole cell
Perkin Elmer
USE OF A COLLISION/REACTION CELL
IN QUADRUPOLE-BASED ICP-MS: GENERAL CONCEPT
 Analyte & interfering ions in / analyte ions out
PerkinElmer-SCIEX
Dynamic Reaction Cell
ICP-MS
PerkinElmer-SCIEX
Dynamic Reaction Cell
ICP-MS
PerkinElmer-SCIEX
Dynamic Reaction Cell
ICP-MS
DIFFERENCES BETWEEN
DIFFERENT TYPES OF COLLISION/REACTION CELLS?
 Hexapole & octopole cell
► Guide ions from point a to point b
 Quadrupole cell
► Guides ions from point a to point b
► Can be used as a mass filter
 Slightly different ways of application
PERKIN ELMER DYNAMIC REACTION CELL – DRC
 Typical use: highly reactive gases
► Determination of Fe
• 40Ar16O+ + NH3  40Ar16O + NH3
+
• 56Fe+ + NH3  NO reaction
► Determination of Fe
• 40Ar16O+ + CO  40Ar+ + CO2
• 56Fe+ + CO  NO reaction
► Determination of Pd
• 90ZrO+ + O2  90ZrO2
+
• 106Pd+ + O2  NO reaction
► Determination of S
• 32S+ + O2  32SO+ + O
• 16O2
+ + O2  NO reaction
charge transfer to reaction gas
atom transfer from reaction gas
atom transfer to reaction gas
atom transfer from reaction gas
PERKIN ELMER DYNAMIC REACTION CELL – DRC
THEORETICAL CONSIDERATIONS
 Reaction is thermodynamically allowed (G < 0)
► ~ exothermic reaction (H < 0)
► ion-molecule reaction MAY proceed
► is usually fast
 Reaction is thermodynamically not allowed (G > 0)
► ~ endothermic reaction (H > 0)
► ion-molecule reaction will not proceed
► no energy is being supplied
 Consultation of thermodynamic / kinetic data
PERKIN ELMER DYNAMIC REACTION CELL – DRC
OPTIMIZATION OF REACTION GAS FLOW RATE
0 0.2 0.4 0.6 0.8 1.0
IonSignal,cps
10
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
Ultrapure water
100 ng/L Fe
40Ar16O+ + NH3  40Ar16O + NH3
+
56Fe+ + NH3  NO reaction
interference-free determination of Fe
reaction gas flow rate (mL/min)
PERKIN ELMER DYNAMIC REACTION CELL – DRC
OPTIMIZATION OF REACTION GAS FLOW RATE
0 0.2 0.4 0.6 0.8 1 1.2
CO gas flow rate (mL/min)
0.1
1
10
100
1000
I(Fe)/Ibackground
56
54
57
58
ONLY ions within the
bandpass are transmitted
SIDE REACTIONS WHEN USING REACTIVE GASES ?
TACKLED BY USING QUADRUPOLE AS MASS FILTER
Ar+
CH 4
CH 3
+
CH 2
+
C H2 3
+
C H2 5
+
C H O3 7
+
ArH
+
C Hn x+1
+
CH 4
+
C Hn x-1
+
CH 4
CH 4
CH 4
CH 4
CH 4 C H
n x
C H
n x
C H O3 6
C H O3 6
C H O3 6
C H O3 6
m/z
B Mg Al Ca Fe Co Se
+ + + + + + +
 Bandpass can be shifted in synchronicity with the mass analyzer
Figure from Scott Tanner / Sciex
Newly formed unwanted ions are
ejected from the cell & do not take
part in further reactions.
Newly formed unwanted ions are
ejected from the cell & do not take
part in further reactions
SIDE REACTIONS WHEN USING REACTIVE GASES ?
TACKLED BY KINETIC ENERGY DISCRIMINATION
 Ions produced inside the hexapole / octopole cell
► Velocity ~ 0
 Ions extracted from ICP
► Higher velocity
 selection of ions according to their velocity or Ekin
► Accomplished via decelerating potential = energy filter
► ‘Kinetic energy discrimination’
BACKGROUND SPECTRUM WITH / WITHOUT
H2/HE PRESSURIZED HEXAPOLE COLLISION CELL
Figure from Thermo Scientific
ALTERNATIVE USE OF KINETIC ENERGY DISCRIMNATION
USE OF INERT GAS (HELIUM) ONLY
 Molecular ions are larger and thus, undergo more collisions
► Loose more Ekin than atomic ions
 Energy barrier selectively discriminates against molecular ions
BACKGROUND SPECTRUM WITH / WITHOUT
HE-ONLY PRESSURIZED OCTOPOLE COLLISION CELL
With empty octopole cell Octopole cell with He
Figures from Agilent’s ICP-MS primer
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 Agilent 7700
► Octopole Collision reaction cell
► Preferred modus of operation
• Use of He as inert collision gas & kinetic energy discrimination
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 Perkin Elmer Nexion
► Quadrupole reaction cell
► Preferred modus of operation
• Use of He as inert collision gas & kinetic energy discrimination
• Use of reaction gases for selective ion-molecule reaction
PERKIN-ELMER NEXION
UNIVERSAL CELL TECHNOLOGY
 Use as Q-based reaction cell with mass filtering capabilities
and
 Use as collision cell with kinetic energy discrimination
Figure from Perkin Elmer
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 ThermoScientific ICAP-Q
► Flatapole reaction cell
► Preferred modus of operation
• Use of He as inert collision gas & kinetic energy discrimination
• Use of reaction gases for selective ion-molecule reaction
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 ThermoScientific ICAP-Q
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 Bruker Aurora M80
COLLISION/REACTION INTERFACE – CRI
BRUKER AURORA M90
Figure from Bruker website
 Introduction of reaction gas (H2 + He) via skimmer in plasmajet
COLLISION/REACTION INTERFACE – CRI
BRUKER AURORA M90
ICP-MS/MS OR ICP-QQQ
 Agilent 8800
► Introduced in 2012
► Quadrupole filter 1 / Octopole reaction cell / Quadrupole filter 2
• Double mass selection
PRESENT-DAY QUADRUPOLE-BASED
ICP-MS INSTRUMENTS
 Agilent 8800 ICP-QQQ
► Superior tool for avoiding spectral overlap
SECTOR FIELD ICP-MS
(HIGH RESOLUTION ICP-MS)
SECTOR FIELD ICP-MS
entrance slit
exit slit
selection of mass resolution setting R = 300, 4000 or 10000
reverse
Nier-Johnson geometry
SEPARATION OF IONS IN A MAGNETIC SECTOR
ion source
acceleration over
potential difference V
detector
(e.g., photographic plate)
qV
2
mv
E
2
kin 
V
magnetic field or
B-field
USE OF AN ELECTROSTATIC SECTOR
AS ENERGY FILTER
ion source
+ electrode
- electrode
energy filtering leads to improved mass resolution
qE
E2
qE
mv
r
qE
r
mv
F
kin
2
2


COMBINATION OF
ELECTROSTATIC AND MAGNETIC SECTOR
ion source
acceleration
electrostatic
sector
magnetic
sector
detector
high mass resolution / huge loss in transmission efficiency
DOUBLE-FOCUSING SET-UP
NIER-JOHNSON GEOMETRY
magnetic
sector
electrostatic
sector
acceleration
detector
ion source
high mass resolution / limited loss in transmission efficiency
DOUBLE-FOCUSING SECTOR FIELD MS
OF REVERSE NIER-JOHNSON GEOMETRY
Double-focusing sector field MS
of reverse Nier-Johnson geometry
Mass analysis in
a magnetic sector
Reverse Nier-Johnson geometry
 Major clean-up of ion beam
Improved background & abundance sensitivity
SECTOR FIELD ICP-MS
SECTOR FIELD ICP-MS
‘HIGH RESOLUTION’ ICP-MS
3 pre-defined R-settings
300, 4000, 10000
low R high R
DEFINITION OF MASS RESOLUTION – 1
 used for calculation of instrumental R
m
m
R


DEFINITION OF MASS RESOLUTION – 2
10% VALLEY DEFINITION
 Calculation of mass resolution that is required
m1 m2
0
0.05
0.1
0.15
0.2
0.25
0.3
signal intensity (arbitrary units)
12
21
mm
2
mm
R






 

SECTOR FIELD ICP-MS
‘HIGH RESOLUTION’ ICP-MS
64.91 64.93 64.95 64.97 64.99
mass-to-charge ratio
0
500
1000
1500
2000
2500
signal intensity (counts/s)
Cu65 +
S O H32 16 1 +
2
S O33 16 +
2
BCR candidate CRM 609
Determination of Cu in groundwater
At low R: overlap of 63Cu+ and 40Ar23Na+, is 65Cu+ interference-free?
EFFECT OF MASS RESOLUTION SETTING
ON SIGNAL INTENSITY
R = 300
R = 4000
R = 10000
0
100000
200000
300000
400000
0 2000 4000 6000 8000 10000 12000
Massaresolutie
SignaalintensiteitvoorIn-115
PRESENT-DAY SECTOR FIELD ICP-MS INSTRUMENTS
OFFERING HIGH MASS RESOLUTION
 Thermo Scientific Element 2 / Element XR
PRESENT-DAY SECTOR FIELD ICP-MS INSTRUMENTS
OFFERING HIGH MASS RESOLUTION
 Nu Instruments AttoM
OTHER TYPES OF
ICP-MS INSTRUMENTATION
TIME-OF-FLIGHT (TOF) ANALYZER
Acceleration
(ΔV)
detection
field-free flight tube
+
+
t0
+ +
t1
+ +
t2
USE OF TOF-ANALYZER IN ICP-MS
 Ions have to be introduced pulse-wise (no continuous introduction)
► Otherwise: simultaneous arrival at detector of
• heavy ion introduced at t & lighter ion introduced at t + t
• ICP = continuous ion source
► beam modulation required
introduction of package of ions into TOF-analyzer
time interval required for mass analysis
ORTHOGONAL ACCELERATION
AS A MEANS OF BEAM MODULATION
repeller
acceleration
ion lenses
ICP
flight tube
extraction region
sampling cone & skimmer
+ V + V
Up to 30 kHz !
USE OF ION MIRROR (REFLECTRON) IN TOF-ICP-MS
TO IMPROVE MASS RESOLUTION
ion, mass m, E1
ion, mass m, E2
reflectron
or
ion mirror
E2
acceleration
E2 > E1
detector
E1
ORTHOGONAL ACCELERATION
AS A MEANS OF BEAM MODULATION
GBC OptiMass 9500
ICP-TOF-MS
FIGURES OF MERIT OF TOF-ICP-MS
 Simultaneous handling of ions extracted from ICP
 Fast + pronounced multi-element capabilities
► up to 30,000 full mass spectra per second
► well-suited for transient signals with short duration
• ETV-ICP-MS
• LA-ICP-MS
• GC-ICP-MS
 Sensitivity & LODs
► inferior to ICP-QMS
 Other figures of merit
► Unit mass resolution or better
► similar to ICP-QMS in many ways
 No commercial success (so far) …
FIGURES OF MERIT OF TOF-ICP-MS
 Most promising for LA-ICP-MS applications
► e.g., single-shot analysis of NIST SRM 612 glass (FWHM = 0.30 s)
0
50
100
150
200
250
300
350
15 16 17 18 19 20
time (s)
signal(arbitraryunits)
Ag107 Ag109 Au Ba137 Ba138
Bi Co Cu63 Cu65 Ga
Ga71 La Ni58 Ni60 Pb204
Pb206 Pb207 Pb208 Rb87 Sr86
Sr87 Sr88 U Zn64 Zn66
Zn67
DOUBLE-FOCUSING SECTOR FIELD MS
OF MATTAUCH-HERZOG GEOMETRY
 All ion beams focused in one focal plane
► Detector with 4800 miniaturized semi-conductor based detectors
► Simultaneous monitoring of entire elemental mass spectrum (Li to U)
electrostatic
sector
entrance
slit
ICP ion
source
magnetic
sector
DOUBLE-FOCUSING SECTOR FIELD MS
OF MATTAUCH-HERZOG GEOMETRY
 Introduced commercially @ Pittcon-2010 by Spectro
DOUBLE-FOCUSING SECTOR FIELD MS
OF MATTAUCH-HERZOG GEOMETRY
 Simultaneous monitoring of entire elemental mass spectrum
DOUBLE-FOCUSING SECTOR FIELD MS
OF MATTAUCH-HERZOG GEOMETRY
 Simultaneous monitoring of entire elemental mass spectrum
MULTI-COLLECTOR ICP-MS
A DEDICATED TOOL FOR ISOTOPIC ANALYSIS
Isotope ratio precision:
down to 0,002 % RSD !
ARRAY OF FARADAY COLLECTORS:
SIMULTANEOUS MONITORING OF ION SIGNAL INTENSITIES
1 2 3 4 5 6 7 8 9 10
measurementnumber
250
270
290
310
330
350
370
390
signal intensity
0
0.2
0.4
0.6
0.8
1
1.2
Isotope ratio
isotope 1
isotope 2
isotope ratio
 Simultaneous monitoring:
► Automatic correction for signal instability & signal drift
► Higher isotope ratio precision
 With ICP-MS instrument equipped with only one detector:
► Mimicked by fast ‘hopping’
Isotope ratio precision:
down to 0,002 % RSD !
ION BEAMS  FARADAY COLLECTORS ?
Zoom optics
Moveable detectors
(motorized)
The ion beams are steered into the appropriate
collectors by applying suitable voltages on the zoom
“optics” (= electrostatic lenses).
The position of the Faraday collectors can
be optimised with respect to the respective
ion beams
Or a combination of both …
FARADAY COLLECTOR – OPERATING PRINCIPLE
VR = 1011 Ω
ion beam
e
Compared to electron multiplier:
► Analog amplifier
► Less sensitive
► No detector dead time
► Very long lifetime
ICP-MS
FIGURES OF MERIT
FIGURES OF MERIT OF ICP-MS
LIMITS OF DETECTION - LODS
 Lowest detection limits attainable
QUADRUPOLE-BASED ICP-MS
LIMITS OF DETECTION – LODS
 < 0.1 – 1 ng/L
 1 – 10 ng/L
 10 – 100 ng/L
 0.1 – 1 µg/L
 1 – 10 µg/L
“Simultaneous” determination @ high sample throughput
FIGURES OF MERIT OF ICP-MS
LINEAR DYNAMIC RANGE
Dual mode electron multiplier (pulse counting vs. analog mode)
ADVANTAGES OF ICP-MS
RELATIVELY SIMPLE MASS SPECTRA
Wavelength  (nm)
0 0 0 0 0,0055 0,72 0 0
99,2745
0 0
0
20
40
60
80
100
120
230 231 232 233 234 235 236 237 238 239 240
m/z value
signalintensity
M+ signals at m/z values of isotopes
Signal pattern displays isotopic composition
ADVANTAGES OF ICP-MS
 Low limits of detection
 Multi-element capabilities
 Wide linear dynamic range
 High sample throughput
 Relatively simple spectra
 Ease of combination with
► Alternative sample introduction systems
► Chromatographic separation techniques
 Ability to obtain isotopic information
DISDVANTAGES OF ICP-MS
 Purchase price
► Quadrupole-based ICP-MS ~ 150,000 €
► Sector field ICP-MS ~ 350,000 €
► Multi-collector ICP-MS ~ 600.000 €
 Costs of operation
► High purity Ar gas (20 L/min)
► Consumables
 Spectral interferences
► Collision/reaction cell in ICP-QMS
► High mass resolution in ICP-SFMS
► No solution in
► TOF-ICP-MS
► Mattauch-Herzog ICP-MS
DISDVANTAGES OF ICP-MS
OPERATING COSTS (PER YEAR IN US $)
155001100010003500ICP-MS
6800230010003500ICP-OES
56005000400200Furnace
AA
400013002002500Flame AA
TotalSuppliesPowerGasesTechnique
155001100010003500ICP-MS
6800230010003500ICP-OES
56005000400200Furnace
AA
400013002002500Flame AA
TotalSuppliesPowerGasesTechnique
Calculated taking into account an average of 4 hrs of operation / day = 1000 hrs / year