Benefits of ICP-qqq-MS

in MS/MS mode for

challenging clinical

trace element

applications

Dr Raimund Wahlen

Agilent Technologies

raimund_wahlen@agilent.com

07920 -466 161

Transforming ICP-MS

Technology

1 October 15, 2013

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

2 October 15, 2013

Some Common Polyatomic Spectral Interferences

for Analysis of Clinical Samples by ICP-MS

Ion Interfering ion 51V+ 35Cl16O+ 52Cr+ 40Ar12C+ 59Co+ 43Ca16O+ 60Ni+ 44Ca16O+ 63Cu+ 40Ar23Na+ 66Zn+ 32S16O18O 75As+ 40Ar35Cl+ 78Se+ 38Ar40Ar+ 80Se+ 40Ar40Ar+ 95Mo+ 79Br16O+ 98Mo+ 81Br16O1H+ 103Rh+ 40Ar63Cu+ 111Cd+ 95Mo16O+

In addition you can get isobaric interferences (eg 40Ar+ on 40Ca+) and doubly-

charged interferences (eg 160Gd++ on 80Se) on target isotopes

Page 4

Energy Energy

Cell Entrance

Cell Exit

Energy loss from each collision with a He atom is the same for analyte and polyatomic ion, but polyatomics are bigger and so collide more often

At cell entrance, analyte and polyatomic ion energies overlap. Energy spread of both groups of ions is narrow, due to ShieldTorch System

Polyatomic ions

Analyte ions

Polyatomic ions

Analyte ions

Energy distribution of analyte and interfering polyatomic ions with the same mass

Bias voltage rejects low energy (polyatomic) ions

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)

Principle of Helium Collision Mode and Kinetic Energy Discrimination (KED)

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

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++)

Complex matrix in no gas (above) and

He mode (right, with 10ppb std inset)

7700 removes ALL polyatomics

7700 - He mode for Polyatomic Interferences

No gas mode (left) and He mode (below)

5 October 15, 2013

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

Reactive interferences are converted to product ions at a new mass – can

be rejected by analyzer quad, which is set to original analyte mass

How Reaction Mode Works in ICP-QMS

Reaction

product ion

On-mass

interference

Analyte

Reaction

gas

Interferenc

e M+

MR+

Analyte and

interfering ions

enter reaction

cell

Quad set to original

analyte mass – rejects

interference product

ion(s)

Analyte

Interference

reacts to form

product ion

6 October 15, 2013

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

Reactive analyte is converted to product ions at a new mass –

interferences remain at original mass and are rejected by analyzer quad

How Reaction Mode Works in ICP-QMS

Original

interfering

ion

On-mass

interference

Analyte

Reaction

gas

Analyte

M+ MR+

Analyte and

interfering ions

enter reaction

cell

Quad set to analyte

product ion mass –

rejects original

interfering ions

Analyte

product ion

Analyte reacts

to form product

ion

7 October 15, 2013

Limitations of Reaction Mode in ICP-QMS

Limitations of reactive cell gases in quadrupole ICP-MS are well-

documented:

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.

8 October 15, 2013

New 8800 ICP Triple Quad MS – unique capabilities

Low flow

sample

introduction

system

High matrix

introduction

(HMI)

technology

Fast, frequency-

matching 27MHz

RF generator Efficient twin-turbo

vacuum system

Dual conical Extraction and

Omega lens focuses ions

across the mass range

9 orders

dynamic range

electron

multiplier (EM)

detector

Analyzer quad Q2:

High frequency

hyperbolic quadrupole

– selects ions that

pass to detector

High-transmission,

matrix tolerant interface

First quad Q1: High frequency

hyperbolic quadrupole mass filter –

selects ions that enter the cell

3rd generation collision/

reaction cell (ORS3)

with 4 cell gas lines

Peltier-

cooled

spray

chamber

Robust, high-temperature

plasma ion source

9 October 15, 2013

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

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

How Reaction Mode Works in ICP-MS/MS

Reaction

product ion

On-mass

interference

Analyte

Off-mass

interference

Reaction

gas

Interferenc

e M+

MR+

Q1 set to analyte

mass – rejects

all non-target

masses

Q2 set to original

analyte mass – rejects

any off-mass product

ion(s)

Analyte

Interference

reacts to form

product ion

All non-target

masses

10 October 15, 2013

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

With ICP-MS/MS, Q1 rejects all non-target masses, ensuring no existing

ions (analyte, matrix, or polyatomic) can overlap new analyte product ion

How Reaction Mode Works in ICP-MS/MS

Original

interfering

ion

On-mass

interference

Analyte

Off-mass

interference

Reaction

gas

Analyte

M+ MR+

Q2 set to analyte

product ion mass –

rejects original

interfering ions

Analyte

product ion

Analyte reacts

to form product

ion

Q1 set to analyte

mass – rejects

all non-target

masses

All non-target

masses

11 October 15, 2013

MS/MS Product Ion Scan - Titanium

Ammonia gas

introduced into

the cell

Q1 set to m/ƶ 48

Q2 scans

spectrum

Spectrum

displays all

resulting ions

from m/ƶ 48

ONLY

October 15, 2013

Confidentiality Label

12

TiNH(NH3)3

TiNH2(NH3)3

Ti(NH3)4

TiNH(NH3)4

TiNH2(NH3)4

Ti(NH3)5

TiNH2(NH3)5

TiNH(NH3)5

Ti(NH3)6

“Ti” 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…

Peaks corresponding to TiNH2(NH3)4 and Ti(NH3)6 selected for

Neutral Gain Scans

Q1 set to let in only m/ƶ 46, 47, 48, 49, 50 INDIVIDUALLY

Q2 set to transition masses:

Q1 +84amu [TiNH2(NH3)4]

Q1 +102amu [Ti(NH3)6]

Therefore transitions used:

46 130 46 148

47 131 47 149

48 132 48 150

49 133 49 151

50 134 50 152

MS/MS Neutral Gain Scan – Titanium with

Ammonia Adducts at Two Mass Transitions

October 15, 2013

Confidentiality Label

13

Q2 set to Q1 +84amu [TiNH2(NH3)4] & +102amu [Ti(NH3)6]

Serum and Urine Check

Based upon results from this HNO3 standard the system was run using basic

preparation for clinical samples (dilution into NH4OH, EDTA, Triton-X, BuOH)

• Standards were prepared in the basic preparation medium

• Standard addition NOT used

• Both diluted serum and urine (10x) run within same batch against same

calibration

• Data compared to no cell gas and other gas modes

Ti in clinical matrices

Target 47 -> 131 Ti [ NH3 ] 48 -> 132 Ti [ NH3 ] 49 -> 133 Ti [ NH3 ] 50 -> 134 Ti [ NH3 ]

Sample Name Conc. [ ug/l ] Conc. [ ug/l ] Conc. [ ug/l ] Conc. [ ug/l ]

Urine Blank 4.6 (2.2-7.0) 2.80 2.79 2.92 2.49

Urine Blank 4.6 (2.2-7.0) 3.50 2.93 3.33 2.66

Urine Trace Elements 14.81 15.27 14.42 15.13

Urine Trace Elements 14.99 15.49 15.50 15.05

Serum L1 1.28 (0.86-1.80) 1.21 1.15 1.14 0.80

Serum L1 1.28 (0.86-1.80) 1.27 1.18 1.09 0.89

Serum L2 1.76 1.92 1.61 1.13

Serum L2 1.82 1.64 1.76 1.22

Multiple calibrations for qualifier isotopes

Allows measurement of SeO+ at product ion mass, after removal of original

Ar2+/REE++ interference, and existing ions at SeO+ product ion mass.

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+ + O2 <cell gas> 96SeO+

40Ar2+, Gd++, Dy++ + O2 no reaction

BUT Q1 of 8800 rejects other ions that would overlap SeO+ at mass 96

80Se16O+

40Ar40Ar+ 160Gd++, 160Dy++

80Se+

96Zr+, 96Mo+, 96Ru+

96Zr+, 96Mo+, 96Ru+

Reaction

gas (O2)

80Se+ 80Se16O+

Q1 (m/z 80) – rejects all

ions apart from m/z 80

Q2 (m/z 96) – rejects all

ions apart from m/z 96

40Ar40Ar+

160Gd++,160Dy++

16 October 15, 2013

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)

No Gas Optimized O2

Serum + Gd 250 ppb 99.87 91.38

Serum + Gd 500 ppb 112.12 91.70

Serum + Gd 1000 ppb 121.07 91.78

17 October 15, 2013

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

18 October 15, 2013

Other Sample Types – Manganese in Whole Blood

Mn is difficult to measure by ICP-

QMS 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

19 October 15, 2013

Conclusions

• Efficient He KED mode suitable for many routine clinical labs

– 8800 can be used in He SQ mode for these elements

• MS/MS reaction cell modes can overcome situations where KED mode is not sufficient:

– 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

20 October 15, 2013

Agilent 8800 QQQ

ICP-MS

The Market Leader in Atomic Spectroscopy

Agilent MP-AES

Agilent 7700 ICP-MS Agilent ICP-OES Agilent AAS

21

Thank You for your attention

Questions?