title: Evaluation of quadrupole-time-of-flight mass spectrometry in comprehensive two-dimensional gas chromatography.
abstract: 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 (50Hz) 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 ≅31.35Hz; two ions ≅16.68Hz; and for 8 precursor ions, a sampling rate of just 4.18Hz 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 (≥600ms) 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 (<5ppm), even for the fastest acquisition operation (50Hz). Spectral deconvolution is demonstrated to work better in GC×GC than in 1D GC mode. Data visualisation in target GC×GC mode presents difficulties when there are overlapping target windows comprising different numbers of precursor ions.
authors.affiliation: Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Rd, Clayton, Vic. 3800, Australia.
authors.forename: Blagoj
authors.initials: B
authors.lastname: Mitrevski
authors.affiliation: Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Rd, Clayton, Vic. 3800, Australia. Electronic address: Philip.Marriott@monash.edu.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Marriott
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D021621:Imaging, Three-Dimensional; D007477:Ions / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
chemical_list: D007477:Ions
keywords: Accurate mass; Comprehensive two-dimensional GC; Deconvolution; Quadrupole time-of-flight MS; Sampling frequency