An Agilent 5975C GC-MS system (Agilent Technologies, Lexington, MA, United States) with a HP-5MS chromatography column (30 m ×0.25 mm × 0.25 μm) was used for chromatographic analysis as described previously (Xu et al., 2020 (link)).
Approximately 5 g of Hua-Feng-Dan powder was mixed with 200 ml water and extracted for 2 h with a volatile oil extractor. The resultant liquid was dissolved in 2 ml of petroleum ether, and the volume was fixed in a 5-ml volumetric flask. GC-MS steam distillation: the program temperature started at 40°C and maintained for 3 min, then increased to 52°C at a rate of 1°C/min, and continued to increase to 160°C at a rate of 20°C/min, and finally increased to 280°C at a rate of 5°C/min, and maintained for 3 min. The carrier gas was nitrogen (99.999%), the volume flow rate was 1 ml/min, the shunt ratio was 10:1, and the injection volume was 1 μl. The solvent was delayed by 3.5 min. The ion source of MS was electron ionization with 70 eV at 230°C. The specific conditions of MS analysis were as follows: interface temperature, 280°C; quadruple temperature, 150°C; full-scan mode, m/z 35–550 amu.
Approximately 5 g of Hua-Feng-Dan powder was mixed with 200 ml water and extracted for 2 h with a volatile oil extractor. The resultant liquid was dissolved in 2 ml of petroleum ether, and the volume was fixed in a 5-ml volumetric flask. GC-MS steam distillation: the program temperature started at 40°C and maintained for 3 min, then increased to 52°C at a rate of 1°C/min, and continued to increase to 160°C at a rate of 20°C/min, and finally increased to 280°C at a rate of 5°C/min, and maintained for 3 min. The carrier gas was nitrogen (99.999%), the volume flow rate was 1 ml/min, the shunt ratio was 10:1, and the injection volume was 1 μl. The solvent was delayed by 3.5 min. The ion source of MS was electron ionization with 70 eV at 230°C. The specific conditions of MS analysis were as follows: interface temperature, 280°C; quadruple temperature, 150°C; full-scan mode, m/z 35–550 amu.