Atmospheric Pressure Gas Chromatography: Background ...

©2011 Waters Corporation 1

Jody Dunstan MS Systems Evaluation,

Manchester

Atmospheric Pressure Gas Chromatography: Background & Applications


What is APGC?


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.


Source and Ion Chamber


How Does it Work?


Mass Spec

Corona Pin

Atmospheric Region

Heated Transfer Line

Capillary GC Column

Ionization Chamber

APGC – How it works


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


The Waters Xevo TQ-S


Xevo TQ Xevo TQ-S

Larger sampling orifice

How did we increase sensitivity?


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.


Elec

tric

Fie

ld

Diffuse Ion

Cloud

Maximising signal

Maximising robustness

Designed to deal with problems associated with a larger sampling orifice


APGC Ionisation Modes & Spectral Characteristics


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


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


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.


Example Data: Dioxins & Furans.

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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.


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


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%


1/10 Dilution of CSL Standard (10 fg TCDD on column)


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


2.230e+007

TCDD C1318.78

114470318.44

min

%

0

100



2.409e+004

TCDD18.791306

18.64 19.05

min

%

0

100



2.212e+004

TCDD18.791149

18.69


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%


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


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


Example Data: Polychlorinated biphenyls (PCBs)


PCB 105 Spectra PCB vs APGC

NIST Spectrum

APGC Spectrum


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.


Chromatography Examples Pentachloro-PCB from CS3

PCB 118

PCB 123


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%


Example Data: Brominated Flame Retardants (PBDEs)


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


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


Example Chromatography – Samples MAT 42 & 48


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.


RADAR – Example Data MAT42

MS Scan BPI trace

PBDE MRM transitions


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


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.


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.

Atmospheric Pressure Gas Chromatography: Background ...

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