Accurate quadrupole MS peak reconstruction in optimized gas-flow comprehensive two-dimensional gas chromatography

In the present research, a split-flow comprehensive 2-D GC-quadrupole MS (qMS) method was developed using: a primary apolar 30 m x 0.25 mm id x 0.25 pm d(f) capillary linked, via a T-union, to a secondary polar 1.0 m x 0.05 mm id x 0.05 mu m d(f) capillary and to a 0.10 m x 0.05 mm id x 0.05 mu m d(f) uncoated column segment. The GC x GC-qMS instrument was equipped with two GC ovens and a loop-type modulator. The polar column was connected to the MS, whereas the uncoated column directed most of the first-dimension effluent to waste and enabled the generation of optimum gas velocities in both dimensions, namely circa 20 and 80 cm/s in the first and second dimensions, respectively. The rapid-scanning qMS was operated at a scan speed of 10 000 amu/s, a 25-Hz data acquisition frequency (scan time + interscan time: 40 ms), and with a normal GC mass range (m/z 40-360). Chromatography bands at the second-dimension outlet were never less than 360 ms wide (6 sigma), enabling the acquisition of at least 10 spectra/peak.