7000a quadrupole gc/ms/ms...ions from the matrix peaks bury the analyte ions) • for ms-drs,...
TRANSCRIPT
7000A Quadrupole GC/MS/MS
• Why GC/MS/MS?
• MS/MS Process and General Benefits
• General Examples of MS/MS Data
• 7000A Hardware description
• 7000A Software description
• Performance Specification
• Performance Data from the 7000A
• Summary
� High Sensitivity
� Fast MRM Speed
� MassHunter Software
� Agilent Reliability
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Why a Quadrupole GC/MS/MS System?
• MS/MS allows for the accurate quantitation of targetcompounds even in high chemical background samples
– MS/MS selectivity means less sample prep
– Sample prep must meet requirements of the GC inlet and column
• Quadrupole MS/MS has better precision and linearity than ion trap MS/MS
• MS/MS provides lower S/N in complex matrices than single quadrupole scan or SIM
• Newer regulations in some markets specify the analytical power of GC/MS/MS
GC/MS Triple Quad (QQQ) for GC/MS/MS
DetectorQuad 1Mass Analysis
Collision Gas (Ar, N2, He)
Quad 2Collision Cell
Ion Source•Ionize Quad 3
Mass Analysis
Carrier Gas (He, H2 )
Mean Free Path
Long LongShort
Collisions No NoYes
MS MS
Multiple Reaction Monitoring (MRM)
170 210 250 290
210
222
268 280165
Quad Mass Filter (Q2)Quad Mass Filter (Q1) Collision Cell
Spectrum with backgroundions (from EI)
Q1 lets onlytarget ion 210 pass through
190 210
210
Collision cell breaks ion 210 apart
150 170 190 210
210158
191
Q2 monitors onlycharacteristic fragments 158 and 191 from ion 210 for quant and qual.
160
158
190
191
no chemical background
MS/MS Eliminates Interferences
analyte
Product 1Product 3
Product 2
Single Quad MSselectivity proportional to
spectral resolutionno selectivity against ions
with same m/z
Triple Quad MSPrecursor selectivity same as MS buthigh probability that at least one of the
product ions will be a unique dissociation product of the precursor only
AND not the interferenceinterference
analyte
interference
unit mass resolution
MS/MS Ensures Lowest Detection Limits
EI: many ions from the source
Q1 SIM isolate precursor before CID
chemical noise eliminated
Product 1Product 3
Product 2
CID +Q2 SIM
Lower m/z Product Ions measured against zero chemical noise
Eliminates the “Invisible” Interferences of SIM
EI-SIMUnit mass resolution
But what happens when a much more intense ion
of a multi-carbon compound has an ion 1 m/z lower?
EI-SIMUnit mass resolution
filters the intense ion that is 1 m/z lower, BUT NOT
the isotope peak from that intensity ion—this
can be a common interference in very ‘dirty’
samples
Isotope ion not removed by SIM
analyte ion
MS/MS eliminates this interference
Removed by SIM
Note: in complex matrices, this isotope interference creates incorrect SIM ratios
and SIM reports with false negatives
103
20 x 103
MS/MS Succeeds Where MS Fails
GC/MS Triple Quad MRM
GC/MS Single Quad SIM
S/N: 116:1 RMS
100 fg HCB
MS SIM
MS/MS MRM A chromatographer’s dream: single peak on flat baseline
Interfering matrix peaks = chemical noise
As Matrix Increases - MS/MS is More Valuable100 fg HCB in Clean Matrix 300 fg HCB in Diesel
Single
MS:
SIM 28
3.8MS
/MS:
283.8
:213.9
S/N=6:1 RMS
S/N=86:1 RMSS/N=37:1 RMS
S/N=26:1 RMS
SIM about equal to MS/MS in clean matrix
MS/MS 15x better than SIM in complex matrix
SIM target
m/z 181
RMS S/N 30 : 1
m/z 219 -> 147
RMS S/N 222 : 1
*
SIM (5973 Single Quad) vs MRM (7000A Triple Quad)a-HCH 3.2 pg injected
Lindanes: MRM Quant Transition 219 147
3.2 pg injected
1.6 pg injected
0.4 pg injected
0.2 pg injected
Page 12
Agilent Innovations in Triple Quad MS
The best technologies from the industry leading 5975C Series GC/MSD
– Heated monolithic gold plated quartz quadrupole
– Proven reliable high performance ion source design
– Low Noise Triple-Axis Detector
…and the 6400 Series LC/MS/MS
– Linear acceleration enhanced hexapole collision cell
– MassHunter software
Inert, high temp source (same as 5975C)
Triple-Axis Detector(as same 5975)
Gold plated quartz, hyperbolic quadrupole(same as 5975C)
Split Flow Turbo
New high performance hexapole collision cell (proprietary design)
High Performance from the Source to the Detector
Inert, high temp source(same as 5975C)
Triple-Axis Detector(as same 5975)
Gold plated quartz, hyperbolic quadrupole
(same as 5975C)
Split Flow Turbo
New high performance hexapole collision cell(proprietary design)
Click on hyperlinked
descriptions for more
details
Hinged access to source and detector
Proven Inert Source Performance
• Several thousands sources in current use
• Solid, inert materials, not a coating that can be damaged by cleaning
• Stay-Clean design extends maintenance intervals with dirty samples
• Source tune parameters in the Autotune file
• Dual filament design reduces maintenance intervals
Partition between source and analyzer compartments
Proprietary Heated Quartz Quadrupole
• High 200C temperature operation results in greater reliability with “dirty” samples
– MS/MS methods typically have more “dirty” samples and benefit even more from the higher temp quad analyzer
• Virtually eliminates the need to clean quads as a maintenance issue
• More stable tunes and methods over a longer period of time in real world sample environments
Analyzer Details
Hinges
Agilent 7000A (QHQ) Design
DetectorQuad 1
Collision Gas (N2 )
Hexapole Collision Cell
Ion Source Quad 2
The hexapole field has excellent transmission effic iency for precursor and product ions
Why a Hexapole: Comparison of Transmission Characteristics
0
0.2
0.4
0.6
0.8
1
1.2
0 500 1000 1500
Transmission
m/z
Mass Range Transmission
Quadrupole Hexapole Octopole
GC/MSm/z=1050
Quadrupoles are the best mass filters (analyzers)Hexapoles and octapole are the best transmission devices
High Performance Collision Cell Design
• Linear acceleration design is optimized for high speed performance
• MRM speed to 500 MRMs/sec allows determination of more compounds per ion group
• High sensitivity with wide mass bandwidth eliminates the need to “tune on your compound” for optimum sensitivity
• Patent pending “Helium Quenching” chemical noise reduction increases S/N
Quadrupole post-filter
Quadrupole pre-filter
Support cradle
(Cell housing and 2 rods removed for clarity)
Why Helium Quenching?Collision Cell Process: Typical Description
Collision Cell
Precursor Ions In
Product Ions Outcollision induced dissociation
1 ml/min N2Collision Gas
Source Detector
Quad Analyzer Quad Analyzer
Why Helium Quenching?Collision Cell Process: Full Description for GC
Collision Cell
Precursor Ions InHe* +
Product Ions Out + He*
In GC/MS, neutral noise is buried in much higher chemical noise.
In GC/MS/MS, chemical noise is greatly reduced so neutral noise is a critical source of noise.
collision induced dissociation
A high population of highly energetic helium metastables are produced in an EI source; since metastable helium is not charged, it can pass through mass analyzer field into the collision cell and through to the HED-EM
1 ml/min N2Collision Gas
At the detector, metastable helium generates neutral noise.
Source Detector
Quad Analyzer Quad Analyzer
Agilent Collision Cell Process with Quench Gas
Collision Cell
Product Ions Out
Precursor Ions InHe* +
collision induced dissociation
1 ml/min N2Collision Gas
Transmission of metastable helium to the detector eliminated = ultra-low neutral noise.
Source Detector
Quad Analyzer Quad Analyzer
He Buffer Gas
He* + He → 2 He + heat
Benefit from “Helium Quench”
Noise Decreased
Helium Quench Gas ON
Helium Quench Gas OFF
tested with hexachlorobenzene
SameSignal
SameSignal
S/N 341:1
S/N 1294:1
High Performance Triple-Axis Detector
• Ultra low neutrals noise
• Long life and high linearity
• “Gain Normalization” corrects tune file for detector aging to allow repeatable long term method sensitivity
• Same design as used in the 5975C GC/MSD
hyperbolic quartztransmission
quadrupoleanalyzer
triple channelelectron multiplier
high energy dynode
steering rod
ion beam
X
Y
OffsetZ
shield for secondary particles
triple channelelectron multiplier
high energy dynode
steering rod
ion beam
XX
YY
OffsetZ
OffsetZ
shield for secondary particles
Technically Superior Design
• Maximum Signal
– Inert MSD source with novel entrance lens
– Highly efficiency, quartz, hyperbolic quadrupole analyzers
– Wide mass bandwidth collision cell
– Increase ion transmission through to the HED-EM
• Minimum Noise– Chemical noise eliminated by MS/MS processes
– Neutral noise eliminated by helium quench gas and Triple-Axis Detector configuration (both unique to Agilent)
Page 26
Smashing Barriers: Agilent 7000A Sensitivity
272:222 Transition180:1 RMS Signal-to-Noise
100fg OFN
Agilent proprietary collision cell innovation led t o this new level of triple quadrupole GC/MS sensitivity
Pesticide Analysis Most Popular Application using GCQQQ
1. Pesticides in Traditional Chinese Medicine (TCM)
2. Pesticides in Tobacco
Page 27
* more pesticides application in “Pesticide Workflo w” talk in the afternoon .
Excellent Result for Qualification in Real Sample - Cyanophos in TCM matrix, NOT solvent
•“ Inert ” Qualifier Ion Ratio0.1ppb(LOD)-1000ppb
Page 28
Excellent Result for Quantitation in Real Sample - Cyanophos in TCM matrix, NOT solvent
R^2=0.99940.2ppb(LOQ)-100ppb(9 Points)
•“ Stable ” Quant AccuracyEven Up to 1000ppb (~104 linear Range)
Page 29
Build up your confidence in Quantitation Results - 1ppb Bromopropylate in TCM matrix, 10 times lower t han Uniform Limit*
RSD = 5.12%
*10 ppb is the uniform limit in Japan Positive List
Page 30
1ppb Cyanophos in TCM Matrix, 6 injection
RSD = 4.83%
Page 31
SIM vs MS/MS Comparison: Chlorpyrifos Not Confirmed in SIM Due to Matrix Interferences!
Chlorpyrifos (28 ppb) Easily Detected and Quantitated by GC/MS/MS – Incurred Carrot
Coun
ts
Resp
onse
s
MassHunter MS Workstation Software
• Modern software interpretation of the proven industry standard GC/MS Chemstation platform
• Single software platform for all Agilent MS Systems
– LC/SQ , LC/QQQ, LC/TOF, LC/QTOF
– GC/SQ, GC/QQQ
– ICP/MS
Triple Quad GC/MS Software Modules
Acquisition
Analysis
Excel Reporting
Instrument Control UI/Navigation
Autotune
• Proprietary program tunes the source, mass analyzer, and detector for (as applicable):
– Ion transmission
– Mass axis calibration
– Mass resolution
– Detector gain vs Voltage
• Autotune settings are saved with the method for repeatable method performance
• Manual Tune override is available
Page 38
Designed for Performance and Reliability
Making femtogram level sensitivity and high speed M RM accessible to a wide range of users
– Leading sensitivity: 100fg of OFN at 100:1 RMS S/N
– High performance MRM with 500 MRMs /sec speed
– New proprietary hexapole collision cell technology
– Reliable, heated gold plated hyperbolic quartz quadrupoles
– Agilent 7890 GC with Capillary Flow technology
– MassHunter Software
Agilent 7000A Triple Quadrupole GC/MSGold Plated Hyperbolic Quartz Quadrupole
Relative Performance of Different MS Modes
• General Summary of Benefits
• Scan versus DRS example
• SIM versus MS/MS example
• Conclusions from ASMS 2008 Poster
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General Statement of the Relative Benefits of Deconvolution and MS/MS
• Amount of improvement depends on nature of the separation and the complexity and intensity of the matrix peaks
– Benefit increases as more coelutions are observed
– Benefit increases as the ratio of the analyte/matrix decreases (intense ions from the matrix peaks bury the analyte ions)
• For MS-DRS, detection limits in matrix are as much as 10x to 50x lower than standard (SIM or scan) methods
• For MS/MS, detection limits in matrix are as much as 100x to 1000x lower than standard (SIM or scan) methods– MS/MS gains in performance are more consistent for more analytes
Report-Spinach Example 1C
All of these compounds were missed due to chemical noise, but AMDIS detected and confirmed all five by NIST05.
Hit number of the top 100 hits from 163,000+ compounds
DRS: Detect the Undetected
DRS A.03 format
Iprodione in Tobacco - SIM could not confirm
Although the plot at m/z 314 might correspond to iprodione, the response at all of the confirmatory ions was over whelmed by the matrix (no distinct peak seen)
Unknown Tobacco Sample – Iprodione 76 ppb
For MS/MS, the quant and qual ions produced cleaned peaks on a simple, flat baseline; ratio of these MRM transitions confirmed iprodione.
Coun
ts
Resp
onse
s
ASMS 2008 Poster Conclusions
Pesticides spiked into neat orange oil (no cleanup)
Poster Title: Bridging the Performance Gap Between GC/MS and GC/MS/MS with Deconvolution TechnologyAuthors: M. Churley, T. Sheehan, P. Zavitsanos, M S zelewski
•MS-DRS lowered LOQ by X10 to X20 for most pesticides but was overwhelmed by intense matrix in some parts of the separation
•MS/MS lowered LOQ by 30x to 100x
•MS/MS consistently detected pesticides in this oil matrix at 20 pg on-column and had sub-pg LOQ for many pesticides