1. X Series ICP-MS Training Course
Introduction to ICP-MS theory and X Series ICP-MS
PlasmaLab
Analytical Method Development
Dealing with interferences

2. Application areas

3. Metals / Industrial Analysis of major, minor and trace elements
Purity of fine metals
Solution Analysis
via nebulisation
Solids Analysis
via Laser Ablation
Reagents required:
40% v/v/ Primar Nitric acid and deionised water
No sample preparation required. Bulk or feature analysis can be performed on metals.

4. Nuclear Fuel quality certification
Environmental and bioassay monitoring of low level actinides
Precise and accurate isotope ratio measurement
Signal to noise ratio needs to be maximized for ppq & sub ppq LOD’s. Use of high efficiency nebulisers.
For waste minimization use of low flow nebulisers, e.g. PFA-50

5. Semiconductor
Determination of low levels of impurities in ultra-pure process reagents
Impurity analysis of wafers
Transition metals suffer from Argon oxide and Argon nitride interferences, which are greatly reduced with the PlasmaScreen Plus and CCT options.
Use ultra-clean glassware, cones etc.
Recommended Accessories: USN and PFA-50, if low sample volume

6. Biological & Clinical Speciation of metals
Elemental uptake and excretion studies
Stable isotope tracer studies
Analysis of salvia, serum, blood and urine
CCT technique recommended to overcome interferences on key elements such as Cr, Fe, As, Se in heavy biological matrices

7. Geological Rocks, sediments and soils
Direct solid analysis using Laser Ablation on:
Individual minerals, thin section, isotope ratios, zonation studies, depth profiling.
Oxide interferences within REE
e.g. BaO on 151Eu and 153Eu, NdO on 150Tb, 160Gd and 162Dy.
Residual HClO4 or saline matrices will interfere with Cr,V and As(ClO & ArCl interferences).

8. Environmental Analysis of drinking and waste water
Seawater and marine life (shellfish, corals etc.)
Analysis of industrial effluents
Soil/sediment studies
Transition metals suffer from Argon oxide and Argon nitride interferences, which are greatly reduced with the CCT option.
Reagents required
40% v/v Primar Nitric acid and deionised water
Sample dried into a digest ‘bomb’, if required.

9. Minimising contamination
Laboratory environment
Water quality
Ultrapure reagents
Handling of ultrapure reagents
Selection of material for containers & cleaning procedures
Sample and standard preparation

10. Tracing sources of contamination
The Step-by-Step Approach
Instrument blank
Water blank
Dilute acid blank
Analysis blank

11. Causes of interferences

12. Interferences – mass spectroscopic

13. Interferences – non mass spectroscopic

14. Isobaric Interference
ELEMENTI ISOTOPI in ICP-MS
Isotopi : Atomi dello stesso elemento con differenti masse
(stesso numero di protoni & elettroni ma diverso numero di neutroni)
Isotopes for Iron Fe
Mass : 55,9116
Isobaric Interference
Mass 54
Isotope for Fe
Isotope for Cr
Isotopes for Chromium Cr
Mass : 52,0554

15. INTERFERENZE
Le interferenze Molecolari e Isobariche vengono classificate come interferenze spettroscopiche
- Interferenze Molecolari (poliatomiche): sono Ossidi ed Idruri, Specie poliatomiche
Gli ossidi possono essere minimizzati attraverso il tuning, gli idruri mediante sistemi per l’abbattimento delle interferenze (CCT)
-Interferenze Isobariche: questo tipo di interferenze sono dovute alla sovrapposizione di diversi isotopi

16. Interferences Spectrometer Lenses (CCT) Ar , N , O , Ar , etc. Ar Ar+
, N
, O 2
, Ar
, etc.
ArO ,
ClO
ArNa
etc.
Ar Ar
(0.1%)
diss
.“metal”, H
0, HNO 3
HCI, etc.
dry “metal” or
metal-oxide,
decomposing
anions
Metal
Atoms
Ions (M )
Conventional “Front-End” approaches to
reduce interferences
“Analyzer approach” to reduce or
resolve interferences M o
> M
+ e -
“Ionization potential”

17. Idruri e doppie cariche Interferenze poliatomiche
ESEMPI DI INTERFERENZE SPETTROSCOPICHE
Interferenze
da Ossidi, Idrossidi,
Idruri e doppie cariche
Interferenze poliatomiche

18. Illustration of overlapping peaks
Interferences
Polyatomic peak overlaps
Causes/sources : solvent
Anions in sample
Cations in sample
Ar gas
Entrained air
Signal suppression
Ionisation suppression or enhancement
Causes/sources : Overloading plasma
Overloading nebuliser
Cone orifice issues
Unintended plasma cooling effects
Elemental peak (isobaric) overlaps
Generally precludes the use of some isotopes if overlap exists
Total measured signal = analyte + polyatomic
Analyte portion
of total measured signal
Illustration of overlapping peaks

19. Correction equations Monoisotopic As in a Cl matrix
Therefore we can calculate
the contribution of ArCl at 77
ArCl
40,35 As 75
ArAr
36,40
ArCl
40,37 Se 77
ArAr
38,40
ArAr
40,40 Se
(82) 75 76 77 78 79 80 81 82

20. Correction equations Monoisotopic As in a Cl matrix76 77 78 79 80 81 82 75 Se
(82)
ArAr
40,40
38,40
36,40
ArCl
40,37
40,35 As
Monoisotopic As in a Cl matrix
Se(77) = Se(82) x AbSe(77)
AbSe(82)
Calculate 77Se contribution at mass 77
from 82Se
Calculate 77ArCl contribution at mass 77
from 77Se
ArCl(77) = Int(77) - Se(77)
ArCl(75) = ArCl(77) x Ab(ArCl(77))
Ab(ArCl(75))
Calculate ArCl contribution at mass 75
from 77ArCl
As(75) = Int(75) - ArCl(75)
Calculate 75As contribution from 75ArCl

21. Instrument performance options
But the X Series ICP-MS, does supply a few ‘hardware’ remedies for these problems…..
PlasmaScreenPlus -
a)‘cool’ screen operation - analysis of Li, Na, K, Ca, Fe
b) ‘hot’ screen operation – enhances sensitivity while maintaining low background
CCT - removal of polyatomics
Xi – improves matrix tolerance and reduces polyatomics

22. Instrument performance options
Isotope
Interferant
Technique
6,7 Li
Background CP 23 Na 24 Mg C 2
CCT 28 Si N 31 P
NOH 56 Fe
ArO
CP,CCT
39,40 K
ArH, Ar 40 Ca Ar 75 As
ArCl 51 V
ClO 52 Cr
ArC 60 Ni
CaO Xi 80 Se

23. PlasmaScreen Plus PlasmaScreenTM Torch
- Grounded metal screen inserted between torch and load coil
- Reliable automatic switching between ‘hot’ and ‘cool’ plasma conditions
Cool screen conditions (~600 Watts)
- Minimizes argon-based interferences i.e. 38Ar1H+, 40Ar16O+, 40Ar2+
- Minimizes high backgrounds associated with easily ionizable elements i.e. Li, Na
- ng/L LODs for Li, Na, Ca, K, Fe, Cr
Hot screen operation
- Enhanced sensitivity
- Low background maintained
- Improved detection limits

24. COOL PLASMA Caratteristiche Vantaggi Limitazioni
RF a bassa potenza: w con nebulizzatore a flusso alto
Temperatura del Plasma prossima a K
Vantaggi
Permette di determinare in ICP-MS elementi come
Ca, Mg, Fe, Na, K, Cr, V
Limitazioni
Plasma non robusto: è necessario analizzare campioni nella medesima matrice
Impossilità di analizzare elementi con alto potenziale di eccitazione/ionizazione ( As, Hg, Se)

25. CCT
Operating the ion guide with a suitable collision/reaction gas (in CCT mode)
Selective attenuation of polyatomic interference ions
40Ar35Cl, 40Ar12C, 40Ar22+, 40Ar2H, 38Ar1H+, 40Ar16O+, 40Ar2+
Innovative, user selectable CCT
Plasma operated at normal power
- Transmission of the analyte ions remains largely unaffected
Ability to switch to CCT mode within sample
SKIMMER CONE
EXTRACTION LENS
SAMPLE CONE
HEXAPOLE RODS

26. CCT - ArAr
59Co+
ArAr+ H2 He
ArAr(neutral) + H2+

27. CCT – analysis of iron
10ppb Fe - CCT
Blank - CCT

28. Collision cell
Based on a multipole ion guide contained in a cell into which the collision cell gases flow; cell is located between the interface and the quadrupole analyser
Hexapole or octopole ion guides are used
Split-flow high-compression turbo pump
Rotary Pump
Detector
Quadrupole
COLLISION CELL
Plasma
MFC 1
MFC 2
Slide Valve
Cell Gas 1
Cell Gas 2

29. Collision cell
Based on a multipole ion guide contained in a cell into which the collision cell gases flow; cell is located between the interface and the quadrupole analyser
Hexapole or octopole ion guides are used
Split-flow high-compression turbo pump
Rotary Pump
Detector
Quadrupole
COLLISION CELL
Plasma
MFC 1
MFC 2
Slide Valve
Cell Gas 1
Cell Gas 2

30. Principi della tecnologia a cella di collisione
Il fascio ionico viene iniettato in una cella pressurizzata
- Tradizionalmente vengono impiegate miscele He, H2 or a He/H2
Gli ioni poliatomici collidono con il gas della celle e vengono dissociati nei loro componenti atomici, ioni etc.
38Ar1H+/39K, 40Ar+/40Ca, 40Ar12C+/52Cr, 40Ar23Na+/63Cu, 40Ar16O+/56Fe,
40Ar35Cl+/75As, 40Ar2+/80Se
La trasmissione degli ioni analiti attraverso la cella non viene praticamante influenzata
Le condizioni di plasma ad alta temperartura vengono mantenute
Ferro
Argon
Ossigeno
Idrogeno
ArO+ Ar H2
H2O+
Fe+
Principles of Collision Cell Technology
The principle of operation is that molecular fragmentation occurs via a range of possible mechanisms thus removing the isobaric overlap.
When operating in CCT mode a collision gas such as H2 and/or He is bled into the cell at a low pressure.
Polyatomic ions collide with the cell gas and are dissociated into their component atoms/ions or converted into non interfering species
Transmission of analyte ions is largely unaffected
The beauty of CCT is that high RF power plasma operation is maintained enabling removal of interferences in complex matrices (e.g. organic solvents) where cool plasma is ineffective
In the example shown: -
Fe+ ions at mass 56 enter the cell and collide with the H2 molecules. H2 is a multi-purpose collision gas and does not react with the Fe+ ions which simply lose a little energy and pass on through to the quadrupole analyser. H2 is drawn away through intermediate turbo pump.
ArO+ (also mass 56) enters the Cell, collides with the H2 gas and the collision dissociates the ArO+ into Ar and H2O+ molecules which are drawn out of the chamber along with the H2. None of the species travel through to the analyser.
.All the commonly occurring molecular species shown can be effectively removed or attenuated with the X7 CCT.
PE system generates reactive intermediate species which react with the ion beam to form adducts which may interfere in other regions in the spectrum. To counteract this PE need a quad pre-filter to deselect regions of the spectrum to remove these adducts. This leads to a more complicated experimental set-up

31. CCTED – Meccanismi possibili
Dissociazione collisionale?
e.g. ArAr+ + He = Ar + Ar+ + He
Reazione chimica?
e.g. ArAr+ + H2 = ArH + ArH+
Trasferimento di carica?
e.g. ArAr+ + H = ArAr + H+
Ritardo collisioneale e successiva flitrazione in termini di energia delle specie?
e.g. ArAr+* + He = ArAr+ + He*
CCTED – Possible Mechanisms
This slide shows possible reaction mechanisms.

32. Solving the problem of cell generated interferences
Subsequent collisions of cell-generated ions cause them to lose kinetic energy
These ions (and also plasma derived polyatomic ions), with their larger collision cross section, lose more energy than the smaller analyte ions
Can prevent these lower energy interfering ions from being detected by using an energy barrier between the cell and the quadrupole analyser – this is called (kinetic) energy discrimination (ED or KED) +

33. How is energy discrimination set up?
Changing collision cell and quadrupole bias voltages provides a simple way to set up the required energy barrier
Polyatomic ions from plasma or cell reaction products have insufficient energy to pass through the energy discrimination barrier
Potential
Position
Without ED
With ED
Potential Barrier
Collision Cell
Lenses
Quadrupole
-2V
-9V
-18V
-14V
Analyte Ion
Isobaric Polyatomic ion
Key
CCTED – Simple Optimization
Tuning for energy discrimination with the X Series is extremely simple requiring the cell pole-bias potential to be adjusted to be slightly negative with respect to the quadrupole pole-bias thus creating an energy barrier at the entrance to the quadrupole. The Energy Discrimination setting is then effective for the full mass range removing the need for optimization for each interfered analyte.
Typical pole bias values of –2V (without ED) and –10v (with ED) are shown in the slide.
During tuning, PlasmaLab software provides a real time display on the computer VDU of user selected analyte and polyatomic responses, enabling the operator to optimise the signal to background ratio.

34. The power of energy discrimination (1)
In environmental and clinical samples, containing Cl and Ca, 75As is interfered by 40Ar35Cl+ and to a lesser extent, 40Ca35Cl+
Collision cells are effective for removing these interferences, however, if ED is not used, a large signal is still observed on 75As
This signal does not match the 3:1 m/z 75 to m/z 77 ratio expected if the interference is Cl - related, so it must be another species
If Ca is not present, the interference is not observed, so it must be related to Ca
CCTED – Simple Optimization
Tuning for energy discrimination with the X Series is extremely simple requiring the cell pole-bias potential to be adjusted to be slightly negative with respect to the quadrupole pole-bias thus creating an energy barrier at the entrance to the quadrupole. The Energy Discrimination setting is then effective for the full mass range removing the need for optimization for each interfered analyte.
Typical pole bias values of –2V (without ED) and –10v (with ED) are shown in the slide.
During tuning, PlasmaLab software provides a real time display on the computer VDU of user selected analyte and polyatomic responses, enabling the operator to optimise the signal to background ratio.
Mass 75 = 17,000 cps
(Mass 77 = 2,000cps)
Scan of 100ppm Ca, collision cell without ED

35. The power of energy discrimination (2)
The interference is believed to be CaOH(H2O)+ or CaO(H3O)+, formed from collision, then reaction, between CaOH+ and H2O in the cell
As the Ca-species forms in the cell it’s energy is immediately reduced relative to the As+ analyte ion; further collisions as it passes through the cell reduce the energy further
Applying a few volts of ED results in elimination of the species
As+ is still transmitted to the quadrupole and can be determined to low ppt levels
CCTED – Simple Optimization
Tuning for energy discrimination with the X Series is extremely simple requiring the cell pole-bias potential to be adjusted to be slightly negative with respect to the quadrupole pole-bias thus creating an energy barrier at the entrance to the quadrupole. The Energy Discrimination setting is then effective for the full mass range removing the need for optimization for each interfered analyte.
Typical pole bias values of –2V (without ED) and –10v (with ED) are shown in the slide.
During tuning, PlasmaLab software provides a real time display on the computer VDU of user selected analyte and polyatomic responses, enabling the operator to optimise the signal to background ratio.
Mass 75 = 6 cps
Scan of 100ppm Ca, collision cell with 2V ED

36. The power of energy discrimination (2)
The interference is believed to be CaOH(H2O)+ or CaO(H3O)+, formed from collision, then reaction, between CaOH+ and H2O in the cell
As the Ca-species forms in the cell it’s energy is immediately reduced relative to the As+ analyte ion; further collisions as it passes through the cell reduce the energy further
Applying a few volts of ED results in elimination of the species
As+ is still transmitted to the quadrupole and can be determined to low ppt levels
CCTED – Simple Optimization
Tuning for energy discrimination with the X Series is extremely simple requiring the cell pole-bias potential to be adjusted to be slightly negative with respect to the quadrupole pole-bias thus creating an energy barrier at the entrance to the quadrupole. The Energy Discrimination setting is then effective for the full mass range removing the need for optimization for each interfered analyte.
Typical pole bias values of –2V (without ED) and –10v (with ED) are shown in the slide.
During tuning, PlasmaLab software provides a real time display on the computer VDU of user selected analyte and polyatomic responses, enabling the operator to optimise the signal to background ratio.
1ppb 75As = 300 cps
Scan of 100ppm Ca + 1ppb As, collision cell with 2V ED

37. Reduction of 40Ar16O+ and Ar2+ using the collision cell
1% HNO3 Blank
1ppb Fe
Quadrupole – Standard Mode
Quadrupole – CCT Mode (H2/He)
Quadrupole – Standard Mode
Quadrupole – CCT Mode (H2/He)
10ppb Se
1% HNO3 Blank

38. Collision cell ICP-MS Fe / Se calibration performance
56Fe (40Ar16O+ attenuated)
80Se (40Ar2+ attenuated)
4.0
14.2
3607
56Fe
1.0
Detection limit (3σ, n = 5) (ppt)
4.3
BEC (ppt)
Correlation coefficient
1648
Sensitivity (cps/ppb)
80Se
Parameter
Sample matrix = 2% HNO3, 8% H2 in He collision gas used

39. Why use oxygen as a collision / reaction gas?
Some interferences cannot be efficiently removed using 'standard' cell gases (e.g. He, H2, NH3)
Some interfered analytes react (along with their interferences), with certain cell gases (e.g. NH3)
Lose analyte sensitivity; degrade detection limit
Kinetic energy discrimination (KED) or bandpass application sometimes not sufficiently effective
Interference suppression results in too much sensitivity loss
BEC's and detection limits not low enough for the analytical requirement

40. XSeriesII – New Proof Data - 1
Fast Cd and Pb in whole blood analysis
Blood reference materials measured; diluted 1:50 for analysis
Standard addition calibration on one sample used to quantify other samples
Unique ability for Thermo! Ideal approach for biomedical samples!
Autosampler probe-to-wash-early function used to maximise throughput
Unique for Thermo!
Sample throughput = 51 per hour, or more than 400 per 8 hour day!
111Cd
499 ± 1
33.3 ± 0.5
Bio Rad 3
Reference 208Pb (ppb)
Reference 111Cd (ppb)
254 ± 2
12.5 ± 0.4
Bio Rad 2
412 ± 13
6.2 ± 0.5
Seronorm blood 2
Measured 208Pb (ppb)
Measured 111Cd (ppb)
Sample identity
208Pb

41. XSeriesII – New Proof Data - 2
Cd in urine in the presence of Mo (removing the MoO interference)
Urine reference material diluted 1:20 with 1% (v/v) HNO3 for analysis; spike recovery (0.50 ppb Cd) performed on sample doped with Mo (5 ppm)
Standard addition calibration on the sample used to quantify other samples
Samples run in standard and collision cell mode with O2 in the cell
O2 promotes MoO+ to higher Mo oxides; Cd does not react
Without O2 the interference is large
96Mo16O+
95Mo16O+
Mo interference
0.02
0.04
Detection limit 3σ (ppb)
5.26
7.98
Conc. (ppb)
Standard mode
Collision cell mode (O2)
Spiked Cd value (ppb)
Isotope
0.05
0.03
Detection limit 3σ (ppb)
0.49
0.50
113Cd
111Cd
Conc. (ppb)
O2 in the cell completely removes the MoO interference!

42. Detection of Pt in 10 ppm Hf solutions
The problems:
HfO+ and HfOH+ interferences on all Pt isotopes (m/z 190 to 198)
m/z 190 and 198 interferences low abundance but 190Pt very low abundance (0.01%) and 198Pt also low (7.2%)
Must suppress HfO+ / HfOH+ interferences on most abundant remaining Pt isotopes (194Pt, 195Pt and 196Pt)
The proposed solution:
Use O2 as the collision gas, to promote formation of higher Hf oxides / hydroxides
Pt less reactive with O2
HfO+, HfOH+ interferences, 10ppm Hf
179Hf16O+ = 3 Mcps
Pt isotopes, 12ppb Pt
195Pt+ = 250 Kcps

43. Pt in 10 ppm Hf, standard mode and O2 data
195Pt standard mode
195Pt collision cell mode (O2) 9 5 7
Detection limit 3σ (ppb)
467*
154*
281*
BEC (ppb)*
Standard mode
Standard BEC / collision cell BEC
Collision cell mode (O2)#
Hf interference
Isotope
0.054
0.006
0.003
12289
0.04
180Hf16O+
196Pt
17111
0.01
179Hf16O+
195Pt
16529
0.02
178Hf16O+
194Pt
BEC (ppb)
* estimated using the 198Pt (linear) calibration sensitivity # O2 flow rate = 2.7 mL/min, non-KED

44. Detection of Hg in 10 ppm W solutions
The problems:
WO+ and WOH+ interferences on all Hg isotopes (m/z 196 to 204)
m/z 196 and 204 interferences low abundance, but 196Hg very low abundance (0.14%) and 204Hg also low (6.8%)
Also have 204Pb interference on 204Hg
Must suppress WO+ / WOH+ interferences on most abundant remaining Hg isotopes (198Hg, 199Hg, 200Hg, 201Hg and 202Hg)
The proposed solution:
Use O2 as the collision gas, to promote formation of higher W oxides / hydroxides
Hg less reactive with O2
WO+, WOH+ interferences, 10ppm W
184W16O+ = 2.4 Mcps
Hg isotopes, 20ppb Hg
200Hg+ = 140 Kcps

45. Hg in 10 ppm W, standard mode and O2 data
200Hg standard mode
200Hg collision cell mode (O2)
1670
0.02
0.2
4.2
334*
184W16O+
200Hg
813
0.03
0.3
1.0
244*
183W16O+
199Hg
0.4 13
Detection limit 3σ (ppb)
247* 12
640*
BEC (ppb)*
Standard mode
Standard BEC / collision cell BEC
Collision cell mode (O2)#
W interference
Isotope
0.05
1235
186W16O+
202Hg 40
184W16O1H+
201Hg
3200
182W16O+
198Hg
BEC (ppb)
* estimated using the 201Hg (linear) calibration sensitivity # O2 flow rate = 3.4 mL/min, non-KED

46. Detection of Cu and Zn in 10 ppm Ti solutions
The problems:
TiO+ (and TiOH+) interferences on all Cu and Zn isotopes (m/z 63 to 70)
m/z 68 and 70 interferences low abundance but 70Zn also low (0.6%)
68Zn most useful in absence of collision cell
Must suppress TiO+ / TiOH+ interferences on Cu and most abundant Zn isotopes
The proposed solutions:
Use O2 as the collision gas to try to promote formation of higher Ti oxides / hydroxides
Compare with kinetic energy discrimination (KED) approach, using H2/He collision gas
TiO+ interferences, 10ppm Ti
47Ti16O+ = 13 Kcps
48Ti16O+ = 130 Kcps
49Ti16O+ = 11 Kcps
Cu / Zn isotopes, 10ppb Cu / Zn
63Cu+ = 85 Kcps
64Zn+ = 68 Kcps
65Cu+ = 42 Kcps

47. Cu, Zn in 10 ppm Ti, standard mode and O2 data
64Zn standard mode
64Zn collision cell mode (O2) 1
0.15
0.17
0.03
0.2
50Ti18O+
68Zn 9
0.05
0.34
0.04
2.9
50Ti16O+
66Zn
0.38
0.06
0.20
Detection limit 3σ (ppb)
20.3
3.1
2.1
BEC (ppb)
Standard mode
Standard BEC / collision cell BEC
Collision cell mode (O2)#
Ti interference
Isotope
0.23
0.11 15
1.35
48Ti16O+
64Zn 17
0.18
49Ti16O+
65Cu 13
0.16
47Ti16O+
63Cu
# O2 flow rate = 7.0 mL/min, non-KED

48. Cu, Zn in 10 ppm Ti, standard mode and H2/He KED data
64Zn standard mode
64Zn collision cell mode H2/He KED 1
0.13
0.25
0.03
0.2
50Ti18O+
68Zn 12
0.02
0.04
2.9
50Ti16O+
66Zn
0.38
0.06
0.20
Detection limit 3σ (ppb)
20.3
3.1
2.1
BEC (ppb)
Standard mode
Standard BEC / collision cell BEC
Collision cell (KED) mode
Ti interference
Isotope
0.05
0.07 62
0.33
48Ti16O+
64Zn 22
0.14
49Ti16O+
65Cu 15
47Ti16O+
63Cu
Data obtained using a 8% H2/He gas flow of 5.5 ml/min and a KED barrier of 3.5V

49. CCTED – Evaluation of Performance
4 Standard Reference Waters were analyzed as ‘unknown’ samples over a 10- hour period
Wide range of typical environmental analytes were measured - 30 analytes, 55 isotopes
Several analytes had associated interference problems….
Experiment- Analytical considerations
In order to evaluate the performance of the X7 ICP-MS, 4 Standard Reference Waters were analyzed as ‘unknown’ samples over a 10-hour period
A number of analytes typically of interest in environmental analysis were monitored.
Over 50 analytical isotopes were used since many the elements of have more than one ‘useful’ isotope for measurement.
Most analytes have few interference problems and are measured in the ‘Standard’ ICP- MS Mode, i.e. with high power plasma without any collision or reaction gas admitted into the cell (cell unpressurized).

50. Experimental - analytical profileLi Be Na Rb Sr Mo Ag Cd Sn Cs Ba Tl Pb U Mg Al K Ca Cr Fe Mn Ni Cu Zn Ga As Se
Analytes V Cr
Experimental - analytical profile
The software groups elements together according to the measurement mode selected such that all elements in Standard mode are measured together, sequentially, in increasing mass, with similar groupings for CCT/ H2 Mode and CCT/NH3 Mode.
This slide shows the analytical profile for this experiment: - as can be seen the in- sample switching with rapid stabilisation between measurement modes combined with the intelligent sample uptake and wash ensures that the X7 ICP-MS provides the fastest possible sample throughput.
The total sample to sample cycle time for analysis of the 55 isotope suite was 3 minutes and 45 seconds. .
Uptake
25s
NH3/He
3x1.6s reps
Settle
Delay
30s
H2/He
3x18s reps
Settle
Delay
30s
Standard
Mode
3x18s reps
Wash
25s
Time Profile
Total Time Per Sample = 3 minutes, 45 seconds

51. Experimental - procedure
Calibration:
Blank
1ppb multi-element solution
10ppb multi-element solution
4 reference water samples analysed as QC checks 12 times over a period of 10 hours against 12 different calibrations
NIST 1640 diluted 1+9 and spiked to 2% HCl
CNRC SLRS-2 spiked to 2% HCl
CNRC SLRS-3 spiked to 2% HCl
CNRC SLRS-4 diluted 1+1 and spiked to 2% HCl
Detection limits calculated by running 10-replicate blank samples 12 times against 12 different calibrations
Experimental – procedure
The autosampler was set up with the following standards and samples. Twelve replicate analyses were performed over a period of 12 hours, recalibrating at the beginning of each cycle.
Calibration was performed with
Blank
1 ppb multi-element standard
10 ppb multi-element standard
Samples
River water reference samples were prepared as follows:
NIST 1640 diluted 1+9 and spiked to 2% HCl
CNRC SLRS-2 spiked to 2% HCl
CNRC SLRS-3 spiked to 2% HCl
CNRC SLRS-4 diluted 1+4 and spiked to 2% HCl
The NIST 1640 and SLRS-4 samples were diluted to reduce the analyte concentrations, providing a greater analytical challenge. All samples were spiked with UPA hydrochloric acid to 2% to increase the presence of chloride-based interference
Detection limits were calculated by running 10-replicate blank samples 12 times against 12 different calibrations

52. Results: stability in different measurement modes -10ppb standard
Each isotope measured in a different mode, switching from NH3 to H2 to Std mode in- sample
10ppb Solution
No internal standard correction
Results: stability in different measurement modes -10ppb standard
In order to compare the relative stabilities and highlight any drift in each measurement mode the 3 Pb isotopes were each measured in different mode during each analytical cycle. 208Pb in standard mode, 207Pb in CCT / H2 mode and 206Pb in CCT / NH3 mode.
Excellent stability of 0.6% RSD was achieved for all isotopes showing that there is no loss of precision when measuring in either of the 2 CCT modes in order to achieve optimum detection limits.
i.e The precision and stability are shown to be independent of the measurement mode required to achieve optimum detection limits and no hysteresis effects are observed when switching modes.

53. Results: stability of real sample in different modes
This slide shows the precisions achieved for the analysis of the NIST 1640 standard with V measured in CCT/NH3 mode, Se measured in CCT/ H2 mode and Cd measured in Normal mode again without reference to any internal standard.
The data shows that there is no loss of data quality due to the continual switching between modes.
Sample diluted and spiked to 2% HCl

54. Results – Method detection limits (g/L)
Results – Method detection limits (ug/L)
Method detection limits were determined by taking 10 replicate blank readings prior to each of the calibration blocks.
The mean 3 sigma MDLs shown here are in the ppt to sub ppt for almost all elements and are well below the regulatory requirements
Based on 3s on 12x10replicates of blank, each from a new calibration

55. Results – accuracy of reference samples
Accuracy is shown here by comparing the measured and certified values for the various CRMs – As can be seen excellent recoveries are obtained all are within +/-10%
All concentrations in g/L
n=12

56. Results – accuracy of reference samples
In summary: -
The analyte concentrations measured in the CRMs in this experiment ranged from ppt to tens of ppm.
This slide shows that that excellent accuracy was achieved over this wide dynamic range and was independent of detector mode (analog or pulse counting), and measurement mode, Normal or CCT Mode.

57. Analysis of Seawater Reference Materials
Direct analysis of seawater is challenging:
Extreme matrix
Severe interferences
Ultra trace analyte concentrations
Analysed against a matched external calibration
H2/He KED CCT mode used for ALL analytes
Rapid method (~3 min/sample)
No gas switching required
No instrument settings switching required
Easy set-up

58. XSeriesII – New Proof Data (ppt)

59. XSeriesII – New Proof Data (ppt)

60. XSeriesII – New Proof Data (ppt)

61. CCTED Evaluation of Performance - Summary
Provides Ease of Set-up
Auto-tune, performance reports allow fully automated set-up and analysis
Ultimate Flexibility
Single mode runs ( e.g.. Seawater example)
Fast analysis
Mode Switching runs
Ultimate Detection Limits
Handles the most extreme matrices (seawater) to give interference free measurements on difficult analytes
Retains excellent stability and accuracy
Results - Summary
The X Series ICP-MS combines research performance with routine operation.
Challenging environmental samples can be analysed with optimised CCT settings with rapid switching between settings. Two different cell gases can be combined with normal mode analysis in a single sample acquisition to provide optimum sample throughput with protocol compliance.
Typical sample throughput is < 4 minutes per sample with up to 55 isotopes per sample. Excellent stability is obtained independent of the measurement mode with RSDs <1% over a 12-hour period.
 Within sample mode switching allows the optimum conditions for each analyte to be used, resulting in the ultimate analytical performance resulting in detection limits in the ppt to sub-ppt range for most elements.
The CCT technique ensures results are obtained with freedom from many interferences. In this study, accuracy to within +/-5% for the vast majority of analytes has been achieved even after spiking to 700ppm chloride.