| Description |
DB-5MS capillary column (30m *0.25mm*0.25μm, Agilent J&W Scientific, Folsom, CA, USA), the carrier gas is high-purity helium (purity is not less than 99.999%), the flow rate is 1.0mL/min, and the temperature of the inlet is 260 C. The sample volume is 1μL, and the sample does not flow into it, and the solvent delay is 4.8min. Programmed temperature rise: the initial temperature of the column temperature box is 60 C and kept for 0.5min; Heat up to 125 C; by 8C/min Program; 8C/min to 210 C;15C/min to 270C; 20c/min, raise the temperature to 305C and keep it for 5min. Electron bombard mention source (EI), ion source temperature 230 C, quadrupole temperature150C, electron energy 70eV. The Sanning mode is full scanning mode (scan), and the quality scanning range is m/z 50-500. The obtained GC/MS raw data in .D format were transferred to .aft format via software Analysis Base File Converter for quick retrieval of data. Then, data were imported into software MS-DIAL, which performs peak detection, peak identification, MS2Dec deconvolution, characterization, peak alignment, wave filtering, and missing value interpolation. Metabolite characterization was based on LUG database. A data matrix was derived. The three-dimensional matrix includes: sample information, the name of the peak of each substance, retention time, retention index, mass-to-charge ratio, and signal intensity. In each sample, all peak signal intensities were segmented and normalized according to the internal standards with RSD greater than 0.1 after screening. After the data was normalized, redundancy removal and peak merging were conducted to obtain the data matrix. |
