Agilent 7890a gc ms system

Acetonitrile, ethyl acetate, n-hexane (all GC grade), and sodium chloride (analytical grade) were supplied by Merck KGaA, (Darmstadt, Germany); AA (purity ≥ 99.9%), and the internal standard (IS) AA⁻¹³C₃, hydrobromic acid (48% w/w aq.), sodium thiosulfate pentahydrate, potassium bromide (both analytical grade) were purchased from Sigma Aldrich (St. Louis, MO, USA); bulk C18 (size 125 Å 55–105 µm) supplied by Waters (Milford, MA, USA); saturated bromine solution was supplied by Titolchimica (Pontecchio Polesine, RO, Italy). Agilent 7890A GC-MS system coupled to an Agilent 5975C mass selective detector (MSD) (Agilent Technologies, Santa Clara, CA, USA); the column was a Restek Rxi^®-XLB GC (proprietary phase; length × I.D.: 30 m × 0.25 mm; df: 0.25 µm) (Restek, Bellefonte, PA, USA).

GC-MS analysis was performed in an Agilent 7890A GC-MS system (Agilent Technologies, Santa Clara, CA, USA), equipped with a CTC autosampler and a PTV injector. Gas chromatography was performed on a 30 m HP-5 ms UI (Agilent J&W) capillary column (film thickness of 0.25 mm; I.D. of 0.25 µm), while back-flush elution was carried out in a 1.5 m deactivated column with a film thickness of 0.18 mm. The initial column temperature was set at 60 °C for 1 min and then increased to 300 °C at a 10 °C/min rate. The temperature was maintained at 300 °C for 6 min. Total run time was 30 min, followed by a 12 min back-flush run and a solvent delay at 6 min. Helium (99.999%) was used as the carrier gas at a flow rate of 3 mL/min, and injection volume was set at 1 μL. Splitless mode injection was performed at the PTV injector, where the temperature was increased from 270 °C to 350 °C. MS was operated in electron impact ionization mode (EI; 70 eV). Ion source and transfer line temperatures were set at 230 °C and 250 °C, respectively. All mass spectra were acquired in full scan mode between 50 and 600 amu.