©2011 Waters Corporation 1 Jody Dunstan MS Systems Evaluation, Manchester Atmospheric Pressure Gas Chromatography: Background & Applications
©2011 Waters Corporation 1
Jody Dunstan MS Systems Evaluation,
Manchester
Atmospheric Pressure Gas Chromatography: Background & Applications
©2011 Waters Corporation 2
What is APGC?
©2011 Waters Corporation 3
What is APGC
Waters APGC is an optional ion source for Xevo and SYNAPT systems that provides a highly sensitive GC/MS, MS/MS & HDMS capability.
Ionisation by APGC is soft (cf. APCI) and molecular ions are readily detected.
Fragmentation can be induced (CID) to provide information for structural elucidation.
On HDMS SYNAPT instruments, molecular ions and fragments can be separated by shape and size (ion mobility) enabling the separation of some isobaric species (structural isomers).
It is very easy to swap between APGC and ElectroSpray (or other ion source) without venting the instrument in a matter of minutes.
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Source and Ion Chamber
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How Does it Work?
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Mass Spec
Corona Pin
Atmospheric Region
Heated Transfer Line
Capillary GC Column
Ionization Chamber
APGC – How it works
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APGC – How it works
Mass Analyser GC Oven
Corona discharge at needle creates plasma
N2 make-up gas delivered through transfer line interior
N2 meets GC eluent flow at transfer line tip
Analyte Molecules are ionised after GC elution and directed to the mass analyser
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The Waters Xevo TQ-S
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Xevo TQ Xevo TQ-S
Larger sampling orifice
How did we increase sensitivity?
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Ion Block Design
Sampling cone aperture — Increased to 0.8mm diameter
o Approx 5x increase in gas/ion flow
New ion block design
— No supplemental pumping — All ions (and gas) enter StepWave guide
o Approx 200x increase in gas flow o Up to 200x increase in ion flux.
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Elec
tric
Fie
ld
Diffuse Ion
Cloud
Maximising signal
Maximising robustness
Designed to deal with problems associated with a larger sampling orifice
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APGC Ionisation Modes & Spectral Characteristics
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Mechanism of Ionization (I)
N2+●
N2 e-
2e-
2N2
N4+● M●+
M Corona Pin
M●+ M
Charge Transfer
“Dry” source conditions Favored by relatively non-polar compounds
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Mechanism of Ionization (II)
N2+●
N4+●
H2O
H2O+●
H2O
H3O+●
+OH●
[M+H]+
M
Protonation
Modified source conditions eg. with water or methanol present Favored by relatively polar compounds
Corona Pin
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NIST Spectrum
APGC Spectrum
Comparison between fragmentation in EI+ and APGC.
Endosulphan
M+.
©2011 Waters Corporation 16 Time
2.00 4.00 6.00 8.00 10.00 12.00 14.00
%
0
100
ANAPGC240409TEST009 TOF MS AP+ 278.025 0.02Da
6718.75
0.01µg/ml BF Std
Time8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00
%
0
100CSL_200306_204 TOF MS EI+
277.018 0.02Da298
15.98
EI GC TOF 5uL Injection
APGC on TOF 1uL Injection
298cps EI+
671cps AP+
Faster run possible due to atm pressure source and higher res MS
15.98
8.75
~ 10X higher response for APGC
Chromatographic Performance – Flow Rate.
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Example Data: Dioxins & Furans.
©2011 Waters Corporation 18
Dioxin Analysis
Dioxins and dioxin-like compounds (DLC) are by-products of various industrial processes, and are commonly regarded as highly toxic compounds that are environmental and persistent pollutants (POPs).
Analysis must comply with legislative requirements. EPA1613 in USA and (EC) No 152/2009 & 252/2012 in Europe.
The ‘Gold Standard’ for analysis is magnetic sector MS (e.g. Waters AutoSpec).
Magnetic sector MS instruments are complex and difficult to use and require significant user training.
Modern Tandem MS/MS instrument offer high sensitivity, flexibility and ease of use.
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Calibration Standards Congener Concentration (pg/µL)
Name 1/10 CSL* CSL CS0.5 CS1 CS2 CS3 CS4
TCDD 0.01 0.1 0.25 0.5 2 10 40 TCDF 0.01 0.1 0.25 0.5 2 10 40 PCDD 0.05 0.5 1.25 2.5 10 50 200 PCDF 0.05 0.5 1.25 2.5 10 50 200
HxCDD 0.05 0.5 1.25 2.5 10 50 200 HxCDF 0.05 0.5 1.25 2.5 10 50 200 HpCDD 0.05 0.5 1.25 2.5 10 50 200 HpCDF 0.05 0.5 1.25 2.5 10 50 200 OCDD 0.1 1 2.5 5 20 100 400 OCDF 0.1 1 2.5 5 20 100 400
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Peaks Areas, Signal:Noise & Repeatability
RT Name Std. Conc
(pg/µL)
Quantify Area
Qualify Area S/N
18.79 TCDD 0.01 116.5 128.4 10.6 18.36 TCDF 0.01 103.4 146.3 8.8 21.91 PCDD 0.05 597.2 508.0 65.1 21.04 12378 PCDF 0.05 499.3 363.1 27.7 21.72 23478-PCDF 0.05 546.1 423.8 32.5 24.48 123478 HxCDD 0.05 479.8 207.8 60.5 24.56 123678 HxCDD 0.05 573.5 207.8 67.6 24.77 123789 HxCDD 0.05 442.0 261.3 57.1 23.85 123478 HxCDF 0.05 354.7 244.0 13.0 23.94 123678 HxCDF 0.05 401.1 325.4 12.9 24.37 234678 HxCDF 0.05 462.8 294.8 15.3 25.08 123789 HxCDF 0.05 373.2 235.2 10.6 27.39 1234678 HpCDD 0.05 332.9 234.4 40.2 26.33 1234678 HpCDF 0.05 303.2 265.1 46.7 27.97 1234789 HpCDF 0.05 314.4 191.7 40.1 30.85 OCDD 0.1 250.3 321.8 28.4 31.12 OCDF 0.1 286.4 247.1 44.8
Name Mean STDEV % RSD Response
TCDD 0.100 0.010 9.7 TCDF 0.086 0.006 6.5 PCDD 0.467 0.019 4.1 12378 PCDF 0.550 0.018 3.3 23478-PCDF 0.575 0.022 3.9 123478 HxCDD 0.494 0.014 2.8 123678 HxCDD 0.475 0.014 3.0 123789 HxCDD 0.438 0.020 4.6 123478 HxCDF 0.405 0.016 3.9 123678 HxCDF 0.406 0.010 2.5 234678 HxCDF 0.403 0.012 3.0 123789 HxCDF 0.606 0.053 8.8 1234678 HpCDD 0.513 0.031 6.0 1234678 HpCDF 0.462 0.019 4.1 1234789 HpCDF 0.4528 0.028 6.3 OCDD 0.347 0.018 5.3 OCDF 0.412 0.021 5.1
Peak are and Signal to Noise (1/10 CSL) Repeatability (n=10)
%RSD < 10%
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1/10 Dilution of CSL Standard (10 fg TCDD on column)
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TCDD native and 13C transitions (CSL)
min18.10 18.20 18.30 18.40 18.50 18.60 18.70 18.80 18.90 19.00 19.10 19.20 19.30
%
0
100
F1:MRM of 8 channels,AP+334>270
090212_003100 fg TCDD CSL Std
2.136e+007
TCDD C1318.78
109439518.44
min
%
0
100
F1:MRM of 8 channels,AP+332 > 268
090212_003100 fg TCDD CSL Std
2.230e+007
TCDD C1318.78
114470318.44
min
%
0
100
F1:MRM of 8 channels,AP+320 > 257
090212_003100 fg TCDD CSL Std
2.409e+004
TCDD18.791306
18.64 19.05
min
%
0
100
F1:MRM of 8 channels,AP+322 > 259
090212_003100 fg TCDD CSL Std
2.212e+004
TCDD18.791149
18.69
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TCDD Calibration Summary with Ion Ratio
Name Type Std. Conc (pg/µL) RT Area IS Area Response 1º Ratio
(Actual) 1º Ratio (Pred)
Deviation from Ion ratio (%)
090212_002 Standard 0.01 18.79 116.5 120884.7 0.01 0.907 0.851 6.6 090212_003 Standard 0.1 18.79 1149.5 1144702.9 0.1 0.88 0.851 3.4 090212_004 Standard 0.25 18.79 3226.5 1308462.4 0.247 0.851 0.851 -* 090212_005 Standard 0.5 18.8 5780.9 1199261 0.482 0.845 0.851 -0.7 090212_006 Standard 2 18.79 23005.8 1198591 1.919 0.844 0.851 -0.8 090212_007 Standard 10 18.79 145228.7 1400430.1 10.37 0.882 0.851 3.6 090212_008 Standard 40 18.78 509468.7 1235180.4 41.247 0.88 0.851 3.4 090212_009 Solvent 18.82 324.3 0.858 0.851 0.8 090212_011 QC 0.1 18.79 768.2 877233.4 0.088 0.707 0.851 -16.9 090212_012 QC 0.1 18.79 925.0 992782.3 0.093 0.823 0.851 -3.3 090212_013 QC 0.1 18.8 854.2 820440.7 0.104 0.936 0.851 10.0 090212_014 QC 0.1 18.8 831.3 769193.8 0.108 0.906 0.851 6.5 090212_015 QC 0.1 18.8 584.8 690372.9 0.085 0.699 0.851 -17.9 090212_016 QC 0.1 18.78 830.6 758723.5 0.109 0.959 0.851 12.7 090212_017 QC 0.1 18.79 718.2 713968 0.101 0.984 0.851 15.6 090212_018 QC 0.1 18.81 880.7 759527.7 0.116 0.954 0.851 12.1 090212_019 QC 0.1 18.81 748.6 742627.3 0.101 0.923 0.851 8.5 090212_020 QC 0.1 18.8 615.8 632499.7 0.097 0.832 0.851 -2.2
* - 0.25 pg/µL standard was determined to be definitive ion ratio
Deviation < 20%
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Calibration Examples Compound name: TCDDCorrelation coefficient: r = 0.999887, r^2 = 0.999774Calibration curve: 1.02895 * x + -0.00220016Response type: Internal Std ( Ref 1 ), Area * ( IS Conc. / IS Area )Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None
pg/µL-0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0 32.5 35.0 37.5 40.0
Res
pons
e
-0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Compound name: TCDFCorrelation coefficient: r = 0.999778, r^2 = 0.999557Calibration curve: 0.895631 * x + 0.000803103Response type: Internal Std ( Ref 3 ), Area * ( IS Conc. / IS Area )Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None
pg/µL-0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0 32.5 35.0 37.5 40.0
Res
pons
e
-0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Compound name: PCDDCorrelation coefficient: r = 0.999908, r^2 = 0.999815Calibration curve: 0.964773 * x + -0.00660736Response type: Internal Std ( Ref 5 ), Area * ( IS Conc. / IS Area )Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None
pg/µL-0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Res
pons
e
-0
20
40
60
80
100
120
140
160
180
Compound name: 123478 HxCDDCorrelation coefficient: r = 0.999809, r^2 = 0.999617Calibration curve: 0.982402 * x + -0.00204981Response type: Internal Std ( Ref 11 ), Area * ( IS Conc. / IS Area )Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None
pg/µL-0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Res
pons
e
-0
20
40
60
80
100
120
140
160
180
r2 = >0.999
r2 = >0.999
r2 = >0.999
r2 = >0.999
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Calibration Summary
Compound %RSD Calibration
RRF
TCDD 3.3 TCDF 7.9 PCDD 2.8 12378 PCDF 2.8 23478-PCDF 2.1 123478 HxCDD 4.0 123678 HxCDD 4.1 123789 HxCDD 3.5 123478 HxCDF 6.3 123678 HxCDF 5.0 234678 HxCDF 3.0 123789 HxCDF 8.0 1234678 HpCDD 5.8 1234678 HpCDF 4.0 1234789 HpCDF 3.3 OCDD 1.8 OCDF 8.3
Name Coeff. Of
Determination TCDD >0.999 TCDF >0.999 PCDD >0.999
12378 PCDF >0.999 23478-PCDF >0.999
123478 HxCDD >0.999 123678 HxCDD >0.999 123789 HxCDD >0.999 123478 HxCDF >0.999 123678 HxCDF 0.999 234678 HxCDF >0.999 123789 HxCDF 0.998
1234678 HpCDD >0.999 1234678 HpCDF >0.999 1234789 HpCDF >0.999
OCDD >0.999 OCDF 0.998
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Example Data: Polychlorinated biphenyls (PCBs)
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PCB 105 Spectra PCB vs APGC
NIST Spectrum
APGC Spectrum
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Calibration Standard Information
Concentration
Name CS1 CS2 CS3 CS4 CS5
13C 1,2,3,4-TCDD 200 200 200 200 200
PCB 123 2 20 200 1000 4000
PCB 118 12 120 1200 6000 24000
PCB 114 2 20 200 1000 4000
PCB 105 2 20 200 1000 4000
PCB 167 2 20 200 1000 4000
PCB 156 2 20 200 1000 4000
PCB 157 2 20 200 1000 4000
PCB 189 2 20 200 1000 4000
A 13C analogue for each PCB was used as an internal standard, 13C TCDD was used as a syringe standard.
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Chromatography Examples Pentachloro-PCB from CS3
PCB 118
PCB 123
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CS1 Standard, Peaks Areas & Signal:Noise
Compound Rt (min) Peak Area S:N (rms)
PCB 123 17.07 363.6 87.4
PCB 118 16.94 48.9 14.3
PCB 114 17.47 54.4 11.7
PCB 105 18.06 59.0 9.6
PCB 167 19.97 64.0 14.8
PCB 156 20.79 63.1 14.1
PCB 157 20.98 56.9 15.2
PCB 189 23.34 43.6 17.9
Compound %RSD
PCB 123 8.9
PCB 118 4.5
PCB 114 8.0
PCB 105 12.0
PCB 167 11.3
PCB 156 8.5
PCB 157 11.5
PCB 189 8.4
2fg on column, 1 µL injection %RSD < 12%
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Example Data: Brominated Flame Retardants (PBDEs)
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Sensitivity - PBDE 1 ng/mL
Name Pred.RT Trace 1º Trace Area S/N BDE 28 6.86 409.8 > 169.1 409.8 > 328.9 2079.2 266.6
BDE 66 8.09 486.71 > 247.95 486.71 > 407.8 1685 204.3
BDE 47 7.88 486.71 > 247.95 486.71 > 407.8 865.5 157.9
BDE 85 8.61 563.6 > 403.7 563.6 > 405.7 278.6 39.4
BDE 99 8.85 563.6 > 403.7 563.6 > 405.7 308.2 35.3
BDE 100 9.17 563.6 > 403.7 563.6 > 405.7 234.6 33.4
Octa BDE 10.82 643.5 > 483.6 643.5 > 485.7 668.7 84.3
BDE 153 9.46 644.5 > 565.5 644.5 > 405.6 120 19.3
BDE 154 9.75 644.5 > 565.5 644.5 > 405.6 16.9 3.5
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Compound name: BDE 100Correlation coefficient: r = 0.999815, r^2 = 0.999630Calibration curve: 414.51 * x + -1210.14Response type: External Std, AreaCurve type: Linear, Origin: Exclude, Weighting: Null, Axis trans: None
ng/mL-0 100 200 300 400 500 600 700 800 900 1000
Res
pons
e
-0
50000
100000
150000
200000
250000
300000
350000
Compound name: BDE 28Correlation coefficient: r = 0.999449, r^2 = 0.998898Calibration curve: 2017.79 * x + 6829.35Response type: External Std, AreaCurve type: Linear, Origin: Exclude, Weighting: Null, Axis trans: None
ng/mL-0 100 200 300 400 500 600 700 800 900 1000
Res
pons
e
-0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
Linearity Example – BDE 28 & BDE 100
r2 = 0.999
r2 = 0.999
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Example Chromatography – Samples MAT 42 & 48
©2011 Waters Corporation 35
Both the Xevo TQ and Xevo TQ-S tandem quadrupole mass spectrometers are equipped with RADAR – an information rich data acquisition approach.
In RADAR mode MRM data can be collected in parallel to the collection of spectral MS data, in both positive and negative ion modes.
This can be done with little or no impact on the quality of the MRM data.
In RADAR you can accurately quantify target compounds while at the same time track other sample matrix components, arming you with a greater depth of knowledge about your sample.
It is important to recognise that RADAR is only possible because of the instrument’s ability to rapidly alternate between MS, MS/MS, positive and negative ion modes without compromising performance.
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RADAR – Example Data MAT42
MS Scan BPI trace
PBDE MRM transitions
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Untargeted Compound Found in RADAR Scan
Isotope Model
Measured
Mass spectra at peak Rt-11.43 (molecular ion cluster magnified) and a comparison between the measured and theoretical isotope patterns
Br
Br
Br
Br
Br
Br
O
O
HH
HH
H
H
H
H
©2011 Waters Corporation 38
What’s Next?
Persistent Organic Pollutants (POPs) analysis.
— Further collaborations with industry experts. Testing of a wide variety of matrices and comparison with existing ‘gold standard’ techniques.
What else can APGC offer?
— What are ideal applications that would work well with higher flow rates or different column dimensions?
Explore the full potential of HDMS systems.
— e.g. hydrocarbon analysis using ion mobility.
©2011 Waters Corporation 39
Acknowledgments
Prof. Bert van Bavel – MTM Research Centre, Örebro University, Sweden.
Brock G. Chittim, Wellington Labs, Canada. Petr Kukučka, Recetox, Czech Republic. Wim Broer, NOFALAB, The Netherlands.