Agilent 6890 5975 gc ms system

Inositol content was measured by the GC-MS method [58 (link),59 (link)] with minor modifications. A total of 20 mg of freeze-dried powder from tobacco leaves and 1 mL of solvent mixtures (MeOH, H₂O and CHCl₃) were transferred into a 5 mL centrifuge tube. This included 200 μL of 40 μg/mL ribitol as the internal reference, which was extracted for 40 min in the ultrasonic apparatus and centrifuged for 10 min at 15,000 g. A total of 500 μL of supernatant was transferred to a new 2 mL-tube, dried in a vacuum concentrator at room temperature. Derivatization of the dried extract was performed as in Roessner [60 (link)], while samples were analyzed by an Agilent 6890-5975 GC-MS system (Agilent, Santa Clara, CA, USA). An Automatic Mass Spectral Deconvolution and Identification System (AMDIS) (NIST, Gaitherburg, MD, USA) was employed to identify peak retention time and intensities of inositol and the internal reference, ribitol. The relative content of inositol was calculated according to the peak area ratio of the internal reference, ribitol, to inositol.

GC-MS analysis was performed on an Agilent 6890-5975 GC-MS system (Agilent, Palo Alto, USA). The chromatographic separations were carried out via a 5% phenyl methyl siloxane HP-5MS capillary column (30 m × 0.25 mm inner diameter, 0.25 μm film). The oven temperature program was optimized and conducted as follows: initially at 60°C, followed by raise to 100°C (10°C/min, held for 1 min), next, programmed to 110°C (1°C/min, held for 1 min), and after this elevated to 150°C (3°C/min, held for 1 min) and finally to 260°C (10°C/min, held for 5 min). Split injection (1.0 μL) was conducted with a split ratio of 60 : 1 and helium was used as carrier gas with 1.0 mL/min flow rate. The spectrometer was selected in electron-impact (EI) mode, and the ionization energy, scan ranges, and scan rate were set in 70 eV, 40 to 400 amu, and 0.34 s per scan, respectively. The temperatures of inlet and ionization source were 230°C and 250°C, respectively. Identifications of the main compounds (patchoulol alcohol, germacrone, and curdione) were based on comparisons of retention times and mass spectra data with those of authentic samples. The content of each compound in sample was quantified based on the peak area integrated by the analysis programs.