7890a 5975c gas chromatography mass spectrometer

The analyses of collected volatiles from R. potaninii were performed using an Agilent 7890A-5975C Gas Chromatography-Mass Spectrometer (GC-MS) equipped with a DB-WAX column with splitless injection. The analytical conditions of the GC-MS were as follows: the initial oven temperature was maintained at 40 °C for 1 min, increased by 5 °C/min to 170 °C held for 2 min, raised at a rate of 8 °C/min up to 230 °C, and then held at this temperature for 5 min. The inlet temperature was set to 230 °C, and the transfer line was at 250 °C. Injections (5 μL) were made using an auto-sampler in splitless injection mode, under electron impact (EI, 70 eV) and within the scan range of 30–300 amu. Helium gas was the carrier at a flow rate of 1 mL/min. Volatiles were identified using a GC-MSD chemical workstation data-processing system (Agilent) by comparing their mass spectra with data from the equipment database (NIST 05) and authenticated standards.

PDA (potato dextrose agar) and PDB (potato dextros) media were purchased from BD Company, and concentrations of 39 and 24 g/L were used to prepare solid and liquid media, respectively.
All the reagents used in this study were of analytical grade. Hydrochloric acid and sulfuric acid were purchased from Sinopharm Chemical Reagent Co., Ltd. Methyl nonadecanoate (internal standard) was supplied by Sigma. The amino acid content was determined using an L‐8900 automatic amino acid analyzer (Hitachi Ltd.). The fatty acid content was determined by a 7890A‐5975C gas chromatography–mass spectrometer (Agilent Technologies).

Agilent 7890A/5975C gas chromatography mass spectrometer was used with an HP-5 MS capillary column (30 m × 250 μm i.d., 0.25 μm). The carrier gas was chromatographic grade helium, and the constant flow rate was 1.0 mL/min. The temperature program was set as follows: the initial temperature was 60 °C, held for 2 min, increased to 240 °C at a rate of 5 °C/min, then held for 3 min, and raised to 290 °C at a rate of 12 °C/min, maintained for 2 min. Injector temperature was set at 280 °C. Solvent delay was 5 min. Splitless injection mode was used. Injection volume was 1 μL. The mass spectrometry data were obtained in full scan mode (m/z 50 to 650). Electron energy was 70 eV. Identification of compounds was carried out by authentic standards and the NIST library (2014) (Gaithersburg, MD, USA) [14 (link)].