Journal of Chromatography A, 1362 (2014) 262–269
Contents lists available at ScienceDirect
Journal of Chromatography A journal homepage: www.elsevier.com/locate/chroma
Gas Chromatography
Evaluation of quadrupole-time-of-flight mass spectrometry in comprehensive two-dimensional gas chromatography Blagoj Mitrevski 1 , Philip J. Marriott ∗ Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Rd, Clayton, Vic. 3800, Australia
a r t i c l e
i n f o
Article history: Received 17 April 2014 Received in revised form 13 August 2014 Accepted 13 August 2014 Available online 20 August 2014 Keywords: Quadrupole time-of-flight MS Comprehensive two-dimensional GC Accurate mass Sampling frequency Deconvolution
a b s t r a c t Quadrupole time-of-flight mass spectrometry (Q-TOFMS) has been evaluated with respect to its applicability in comprehensive two-dimensional gas chromatography (GC × GC). At a maximum acquisition frequency, while approximately 50 full accurate mass spectra on disk were acquired per s (50 Hz) in scan mode, the sampling rate in target mode (MS/MS) was strongly dependent on the number of target ions selected. The number of selected precursor ions per time window proportionally decreased the acquisition rate for each ion; one precursor ion ∼ =31.35 Hz; two ions ∼ =16.68 Hz; and for 8 precursor ions, a sampling rate of just 4.18 Hz was found. When Q-TOFMS was used in simultaneous mode, where in addition to the acquisition of target ion MS/MS signals, it also collects the full mass spectrum, sampling rates were even lower. It is demonstrated that Q-TOFMS generates sufficient data points over each peak in GC × GC operation in scan mode using TOFMS acquisition only, or is able to collect sufficient data points for relatively wide chromatographic peaks (≥600 ms) in the target mode (MS/MS), however only if one or two precursor ions are selected per time window. Mass accuracy was found to perform within specification (**) for C15 is acquired at two sampling intervals, but now in regions where there are 3 and 4 total PIS per time window. In multi-analyte methods, there are usually cases in which analytes are split across segments. For data reconstruction purposes in GC × GC, managing this effect is critical to analysis. The C14 peak itself is acquired at two different sampling intervals: the first half of the peak at 34 ms (one PIS) and the second half at 66 ms (two PIS). Even though we were able to properly display the alkane peak locations by manually processing each part of the time windows separately by using 2D GC converter and Transform (data not shown), the time and effort heavily outweigh the outcome. In this finding, it is clear that unless a facile data processing procedure is available, complex tandem MS scan protocols will probably not be widely adopted in GC × GC mode.
characteristic ion masses and their collision induced dissociation data; this can be supported by GC × GC retention properties. Further studies are required to explore detailed opportunities for tandem mass spectrometry incorporated into GC × GC separations. Acknowledgements The authors thank Agilent Technologies for facility support. P.J.M. acknowledges the Australian Research Council for a Discovery Outstanding Researcher Award, and grant support: DP130100217. Appendix A. Supplementary data Supplementary material related to this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.chroma.2014.08.053.
4. Conclusions A tandem MS detector with accurate mass (600 ms) only if one or two precursor ions are selected per time window and this limits the applicability of Q-TOFMS MS/MS mode in GC × GC if precise quantification is required. Nevertheless, QTOFMS in full mass acquisition mode at maximum rate generates approximately 50 Hz accurate mass data (20 ms duty cycle) and produces enough data points in GC × GC for proper peak definition and quantification. Since component identification is equally relevant, GC × GC with accurate mass Q-TOFMS provides a unique solution to high-quality characterisation of sample mixtures. File size and data processing can be an issue under these conditions: 2 h operation at 50 Hz generates 30 GB data file size on disk. A justification for use of tandem MS detection in GC × GC methods is the ability to generate increased specificity and to allow unequivocal identification of target analytes on the basis of their
References [1] J.V. Seeley, S.K. Seeley, Multidimensional gas chromatography: fundamental advances and new applications, Anal. Chem. 85 (2013) 557–578. [2] M. Libardoni, J.H. Waite, R. Sacks, Electrically heated, air-cooled thermal modulator and at-column heating for comprehensive two-dimensional gas chromatography, Anal. Chem. 77 (2005) 2786–2794. [3] S.-J. Kim, S.M. Reidy, B.P. Block, K.D. Wise, E.T. Zellers, K. Kurabayashi, Microfabricated thermal modulator for comprehensive two-dimensional micro gas chromatography: design, thermal modeling, and preliminary testing, Lab Chip 10 (2010) 1647–1654. [4] O. Panic, T. Gorecki, C. McNeish, A.H. Goldstein, B.J. Williams, D.R. Worton, S.V. Hering, N.M. Kreisberg, Development of a new consumable-free thermal modulator for comprehensive two-dimensional gas chromatography, J. Chromatogr. A 1218 (2011) 3070–3079. [5] G.S. Frysinger, R.B. Gaines, Comprehensive two-dimensional gas chromatography with mass spectrometric detection (GC x GC/MS) applied to the analysis of petroleum, HRC-J. High Resolut. Chromatogr. 22 (1999) 251–255. [6] M. van Deursen, J. Beens, J. Reijenga, P. Lipman, C. Cramers, J. Blomberg, Grouptype identification of oil samples using comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometer (GC x GC-TOF), HRC-J. High Resolut. Chromatogr. 23 (2000) 507–510. [7] R. Shellie, P. Marriott, P. Morrison, Concepts and preliminary observations on the triple dimensional analysis of complex volatile samples by using GCxGCTOFMS, Anal. Chem. 73 (2001) 1336–1344. [8] N. Ochiai, T. Ieda, K. Sasamoto, A. Fushimi, S. Hasegawa, K. Tanabe, S. Kobayashi, Comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry and simultaneous nitrogen phosphorous and mass spectrometric detection for characterization of nanoparticles in roadside atmosphere, J. Chromatogr. A 1150 (2007) 13–20. [9] T. Ieda, N. Ochiai, T. Miyawaki, T. Ohura, Y. Horii, Environmental analysis of chlorinated and brominated polycyclic aromatic hydrocarbons by comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry, J. Chromatogr. A 1218 (2011) 3224– 3232. [10] S. Hashimoto, Y. Takazawa, A. Fushimi, K. Tanabe, Y. Shibata, T. Ieda, N. Ochiai, H. Kanda, T. Ohura, Q. Tao, S.E. Reichenbach, Global and selective detection of organohalogens in environmental samples by comprehensive two-dimensional gas chromatography-tandem mass spectrometry and highresolution time-of-flight mass spectrometry, J. Chromatogr. A 1218 (2011) 3799–3810. [11] N. Ochiai, T. Ieda, K. Sasamoto, Y. Takazawa, S. Hashimoto, A. Fushimi, K. Tanabe, Stir bar sorptive extraction and comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry for ultra-trace analysis of organochlorine pesticides in river water, J. Chromatogr. A 1218 (2011) 6851–6860. [12] S. Hashimoto, Y. Zushi, A. Fushimi, Y. Takazawa, K. Tanabe, Y. Shibata, Selective extraction of halogenated compounds from data measured by comprehensive multidimensional gas chromatography/high resolution time-of-flight mass spectrometry for non-target analysis of environmental and biological samples, J. Chromatogr. A 1282 (2013) 183–189. [13] S.-T. Chin, Y. Novachai, P.J. Marriott, Enantiomeric separation in comprehensive two-dimensional gas chromatography with accurate mass analysis. Chirality (2014). DOI: 10.1002/chir.22280. [14] A.X. Zeng, S.-T. Chin, A. Patti, P.J. Marriott, Profiling of soil fatty acids using comprehensive two-dimensional gas chromatography with mass spectrometry detection, J. Chromatogr. A 1317 (2013) 239–245. [15] M. Poliak, A.B. Fialkov, A. Amirav, Pulsed flow modulation two-dimensional comprehensive gas chromatography-tandem mass spectrometry with supersonic molecular beams, J. Chromatogr. A 1210 (2008) 108–114. [16] A. Fushimi, S. Hashimoto, T. Ieda, N. Ochiai, Y. Takazawa, Y. Fujitani, K. Tanabe, Thermal desorption—comprehensive two-dimensional gas chromatography
B. Mitrevski, P.J. Marriott / J. Chromatogr. A 1362 (2014) 262–269 coupled with tandem mass spectrometry for determination of trace polycyclic aromatic hydrocarbons and their derivatives, J. Chromatogr. A 1252 (2012) 164–170. [17] P.Q. Tranchida, F.A. Franchina, M. Zoccali, S. Panto, D. Sciarrone, P. Dugo, L. Mondello, Untargeted and targeted comprehensive two-dimensional GC analysis using a novel unified high-speed triple quadrupole mass spectrometer, J. Chromatogr. A 1278 (2013) 153–159. [18] B. Mitrevski, M.W. Amer, A.L. Chaffee, P.J. Marriott, Evaluation of comprehensive two-dimensional gas chromatography with flame photometric detection:
269
potential application for sulfur speciation in shale oil, Anal. Chim. Acta 120 (2014) 55–63. [19] B.S. Mitrevski, P. Wilairat, P.J. Marriott, Evaluation of World Anti-Doping Agency criteria for anabolic agent analysis by using comprehensive two-dimensional gas chromatography-mass spectrometry, Anal. Bioanal. Chem. 396 (2009) 2503–2511. [20] B.S. Mitrevski, P. Wilairat, P.J. Marriott, Comprehensive two-dimensional gas chromatography improves separation and identification of anabolic agents in doping control, J. Chromatogr. A 1217 (2010) 127–135.
Contents lists available at ScienceDirect
Journal of Chromatography A journal homepage: www.elsevier.com/locate/chroma
Gas Chromatography
Evaluation of quadrupole-time-of-flight mass spectrometry in comprehensive two-dimensional gas chromatography Blagoj Mitrevski 1 , Philip J. Marriott ∗ Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Rd, Clayton, Vic. 3800, Australia
a r t i c l e
i n f o
Article history: Received 17 April 2014 Received in revised form 13 August 2014 Accepted 13 August 2014 Available online 20 August 2014 Keywords: Quadrupole time-of-flight MS Comprehensive two-dimensional GC Accurate mass Sampling frequency Deconvolution
a b s t r a c t Quadrupole time-of-flight mass spectrometry (Q-TOFMS) has been evaluated with respect to its applicability in comprehensive two-dimensional gas chromatography (GC × GC). At a maximum acquisition frequency, while approximately 50 full accurate mass spectra on disk were acquired per s (50 Hz) in scan mode, the sampling rate in target mode (MS/MS) was strongly dependent on the number of target ions selected. The number of selected precursor ions per time window proportionally decreased the acquisition rate for each ion; one precursor ion ∼ =31.35 Hz; two ions ∼ =16.68 Hz; and for 8 precursor ions, a sampling rate of just 4.18 Hz was found. When Q-TOFMS was used in simultaneous mode, where in addition to the acquisition of target ion MS/MS signals, it also collects the full mass spectrum, sampling rates were even lower. It is demonstrated that Q-TOFMS generates sufficient data points over each peak in GC × GC operation in scan mode using TOFMS acquisition only, or is able to collect sufficient data points for relatively wide chromatographic peaks (≥600 ms) in the target mode (MS/MS), however only if one or two precursor ions are selected per time window. Mass accuracy was found to perform within specification (**) for C15 is acquired at two sampling intervals, but now in regions where there are 3 and 4 total PIS per time window. In multi-analyte methods, there are usually cases in which analytes are split across segments. For data reconstruction purposes in GC × GC, managing this effect is critical to analysis. The C14 peak itself is acquired at two different sampling intervals: the first half of the peak at 34 ms (one PIS) and the second half at 66 ms (two PIS). Even though we were able to properly display the alkane peak locations by manually processing each part of the time windows separately by using 2D GC converter and Transform (data not shown), the time and effort heavily outweigh the outcome. In this finding, it is clear that unless a facile data processing procedure is available, complex tandem MS scan protocols will probably not be widely adopted in GC × GC mode.
characteristic ion masses and their collision induced dissociation data; this can be supported by GC × GC retention properties. Further studies are required to explore detailed opportunities for tandem mass spectrometry incorporated into GC × GC separations. Acknowledgements The authors thank Agilent Technologies for facility support. P.J.M. acknowledges the Australian Research Council for a Discovery Outstanding Researcher Award, and grant support: DP130100217. Appendix A. Supplementary data Supplementary material related to this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.chroma.2014.08.053.
4. Conclusions A tandem MS detector with accurate mass (600 ms) only if one or two precursor ions are selected per time window and this limits the applicability of Q-TOFMS MS/MS mode in GC × GC if precise quantification is required. Nevertheless, QTOFMS in full mass acquisition mode at maximum rate generates approximately 50 Hz accurate mass data (20 ms duty cycle) and produces enough data points in GC × GC for proper peak definition and quantification. Since component identification is equally relevant, GC × GC with accurate mass Q-TOFMS provides a unique solution to high-quality characterisation of sample mixtures. File size and data processing can be an issue under these conditions: 2 h operation at 50 Hz generates 30 GB data file size on disk. A justification for use of tandem MS detection in GC × GC methods is the ability to generate increased specificity and to allow unequivocal identification of target analytes on the basis of their
References [1] J.V. Seeley, S.K. Seeley, Multidimensional gas chromatography: fundamental advances and new applications, Anal. Chem. 85 (2013) 557–578. [2] M. Libardoni, J.H. Waite, R. Sacks, Electrically heated, air-cooled thermal modulator and at-column heating for comprehensive two-dimensional gas chromatography, Anal. Chem. 77 (2005) 2786–2794. [3] S.-J. Kim, S.M. Reidy, B.P. Block, K.D. Wise, E.T. Zellers, K. Kurabayashi, Microfabricated thermal modulator for comprehensive two-dimensional micro gas chromatography: design, thermal modeling, and preliminary testing, Lab Chip 10 (2010) 1647–1654. [4] O. Panic, T. Gorecki, C. McNeish, A.H. Goldstein, B.J. Williams, D.R. Worton, S.V. Hering, N.M. Kreisberg, Development of a new consumable-free thermal modulator for comprehensive two-dimensional gas chromatography, J. Chromatogr. A 1218 (2011) 3070–3079. [5] G.S. Frysinger, R.B. Gaines, Comprehensive two-dimensional gas chromatography with mass spectrometric detection (GC x GC/MS) applied to the analysis of petroleum, HRC-J. High Resolut. Chromatogr. 22 (1999) 251–255. [6] M. van Deursen, J. Beens, J. Reijenga, P. Lipman, C. Cramers, J. Blomberg, Grouptype identification of oil samples using comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometer (GC x GC-TOF), HRC-J. High Resolut. Chromatogr. 23 (2000) 507–510. [7] R. Shellie, P. Marriott, P. Morrison, Concepts and preliminary observations on the triple dimensional analysis of complex volatile samples by using GCxGCTOFMS, Anal. Chem. 73 (2001) 1336–1344. [8] N. Ochiai, T. Ieda, K. Sasamoto, A. Fushimi, S. Hasegawa, K. Tanabe, S. Kobayashi, Comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry and simultaneous nitrogen phosphorous and mass spectrometric detection for characterization of nanoparticles in roadside atmosphere, J. Chromatogr. A 1150 (2007) 13–20. [9] T. Ieda, N. Ochiai, T. Miyawaki, T. Ohura, Y. Horii, Environmental analysis of chlorinated and brominated polycyclic aromatic hydrocarbons by comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry, J. Chromatogr. A 1218 (2011) 3224– 3232. [10] S. Hashimoto, Y. Takazawa, A. Fushimi, K. Tanabe, Y. Shibata, T. Ieda, N. Ochiai, H. Kanda, T. Ohura, Q. Tao, S.E. Reichenbach, Global and selective detection of organohalogens in environmental samples by comprehensive two-dimensional gas chromatography-tandem mass spectrometry and highresolution time-of-flight mass spectrometry, J. Chromatogr. A 1218 (2011) 3799–3810. [11] N. Ochiai, T. Ieda, K. Sasamoto, Y. Takazawa, S. Hashimoto, A. Fushimi, K. Tanabe, Stir bar sorptive extraction and comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry for ultra-trace analysis of organochlorine pesticides in river water, J. Chromatogr. A 1218 (2011) 6851–6860. [12] S. Hashimoto, Y. Zushi, A. Fushimi, Y. Takazawa, K. Tanabe, Y. Shibata, Selective extraction of halogenated compounds from data measured by comprehensive multidimensional gas chromatography/high resolution time-of-flight mass spectrometry for non-target analysis of environmental and biological samples, J. Chromatogr. A 1282 (2013) 183–189. [13] S.-T. Chin, Y. Novachai, P.J. Marriott, Enantiomeric separation in comprehensive two-dimensional gas chromatography with accurate mass analysis. Chirality (2014). DOI: 10.1002/chir.22280. [14] A.X. Zeng, S.-T. Chin, A. Patti, P.J. Marriott, Profiling of soil fatty acids using comprehensive two-dimensional gas chromatography with mass spectrometry detection, J. Chromatogr. A 1317 (2013) 239–245. [15] M. Poliak, A.B. Fialkov, A. Amirav, Pulsed flow modulation two-dimensional comprehensive gas chromatography-tandem mass spectrometry with supersonic molecular beams, J. Chromatogr. A 1210 (2008) 108–114. [16] A. Fushimi, S. Hashimoto, T. Ieda, N. Ochiai, Y. Takazawa, Y. Fujitani, K. Tanabe, Thermal desorption—comprehensive two-dimensional gas chromatography
B. Mitrevski, P.J. Marriott / J. Chromatogr. A 1362 (2014) 262–269 coupled with tandem mass spectrometry for determination of trace polycyclic aromatic hydrocarbons and their derivatives, J. Chromatogr. A 1252 (2012) 164–170. [17] P.Q. Tranchida, F.A. Franchina, M. Zoccali, S. Panto, D. Sciarrone, P. Dugo, L. Mondello, Untargeted and targeted comprehensive two-dimensional GC analysis using a novel unified high-speed triple quadrupole mass spectrometer, J. Chromatogr. A 1278 (2013) 153–159. [18] B. Mitrevski, M.W. Amer, A.L. Chaffee, P.J. Marriott, Evaluation of comprehensive two-dimensional gas chromatography with flame photometric detection:
269
potential application for sulfur speciation in shale oil, Anal. Chim. Acta 120 (2014) 55–63. [19] B.S. Mitrevski, P. Wilairat, P.J. Marriott, Evaluation of World Anti-Doping Agency criteria for anabolic agent analysis by using comprehensive two-dimensional gas chromatography-mass spectrometry, Anal. Bioanal. Chem. 396 (2009) 2503–2511. [20] B.S. Mitrevski, P. Wilairat, P.J. Marriott, Comprehensive two-dimensional gas chromatography improves separation and identification of anabolic agents in doping control, J. Chromatogr. A 1217 (2010) 127–135.
