Pegasus 2 tof mass spectrometer

A 6890 GC (Agilent) was equipped with Combi PAL autosampler (CTC Analytics), a CIS 4 injector (Gerstel, Mülheim an der Ruhr, Germany), and a J&W DB-FFAP column, 30 m × 0.25 mm i.d., 0.25 µm film thickness (Agilent) used as first column. The carrier gas was helium at a constant flow of 2.0 mL/min. The injection volume was 1 µL. The initial oven temperature of 40 °C was held for 2 min, followed by a gradient of 6 °C/min to a final temperature of 230 °C. The end of the column was connected to a second column, J&W DB-1701, 2.7 m × 0.18 mm i.d., 0.18 µm film thickness (Agilent). A liquid nitrogen-cooled dual stage quadjet thermal modulator was installed at the beginning of the second column and operated with a modulation period of 4 s. The major part of the second column was installed in a secondary oven mounted inside the primary GC oven. The initial oven temperature of the secondary oven was 45 °C and was held for 2 min, followed by a gradient of 6 °C/min to a final temperature of 240 °C. The end of the column was connected to a Pegasus II TOF mass spectrometer (Leco, Mönchengladbach, Germany) via a heated (250 °C) transfer line. Mass spectra were generated in the electron ionisation (EI) mode at 70 eV with a scan range of m/z 35 -350 and a scan rate of 100 spectra/s. For data analysis, the GC Image (Lincoln, NE, USA) software was used.