7890a gc 5975 msd

Morpholine analysis was performed on a GC-MS instrument (7890A GC-5975 MSD, Agilent Technologies, Santa Clara, CA, USA). The analysis method was modified from that described by Cao et al. by changing the analytical column and split ratio, etc. [28 (link)]. Separation was carried out on a DB-1701 column (30 m × 0.25 mm i.d., 0.25 µm film thickness, Agilent Technologies). A DB-wax column (30 m × 0.25 mm i.d., 0.25 µm film thickness, Agilent Technologies) was compared to optimize the method; the DB-1701 column resulted in better separation with a better response (data not shown). The injection volume was 1 μL and the sample was vaporized at 250 °C with a 1:7 split ratio. The GC oven temperature was operated as follows: 100 °C for 4 min, heating to 120 °C at 10 °C/min and held for 3 min, and then heating to 250 °C at 20 °C/min and held for 5 min. The electron energy was 70 eV. The flow rate was 2.0 mL/min of He (99.999%). The transfer line temperature, quadrupole temperature, and electron impact ionization source temperature were held at 280 °C, 150 °C, and 230 °C, respectively. The scan rate was 3.2 scans/s. Four different ions were selected to detect and quantify N-nitroso-morpholine (qualifier ion: m/z 86; quantifier ion: m/z 116) and its isotope (qualifier ion: m/z 64; quantifier ion: m/z 124) in selected ion monitoring (SIM) mode.

The derivatised protein hydrolysates of Xanthomonas oryzae were placed in an automatic liquid sampler (7683B ALS, Agilent Technologies, Santa Clara, CA, USA) and 2 μL was injected into the DBX-5 column using the splitless mode for GC−MS (7890A GC, 5975 MSD from Agilent Technologies, USA) acquisition at the facility of IIT Roorkee. Helium was used as a carrier gas at a constant flow rate of 1.3 mL/min. The temperature of the front injector was operated isothermally at 230 °C. The temperature gradient of 5 min at 120 °C isothermal was used, followed by a 4 °C min⁻¹ oven temperature gradient up to a final 270 °C, and then held for 3 min at 270 °C, followed by a 20 °C min⁻¹ up to a final 320 °C temperature for 1 min. Ions were generated using a 70 eV electron beam in electron ionization mode. The spectra were recorded with a scanning range of 50–600 mz⁻¹ for a total run time of 50 min. Chemstation software (Agilent Technologies, USA) was used to control the data acquisition parameters (both GC separation and mass spectrometry) during all the sample runs.