UPLC–MS/MS Analysis of CHGX Components

An UPLC–MS/MS system (Waters Corp., Milford, MA, United States) equipped with a HESI-II probe was utilized to identify the main components of CHGX, as previously reported (Xu et al., 2018 (link)). The positive and negative HESI-II voltages were set to 3.8 and 3.2 kV, respectively, and the vaporizer temperature was set to 300°C. Both the sheath gas and the auxiliary gas were nitrogen. The collision gas was also nitrogen at a pressure of 1.5 mTorr. The mobile phase was composed of A (0.1% (v/v) formic acid aqueous solution) and B (acetonitrile). The HPLC elution conditions were optimized as follows: 0–1 min: 95% A; 1–2.4 min: 95–90% A; 2.4–13.5 min: 90–68% A; 13.5–18.5 min: 68–10% A; 18.5–19 min: 10–95% A; and 19–21 min: 95% A. The flow rate and the column temperature were set to 0.3 ml/min and 35°C, respectively. Data were collected and processed by Xcalibur 4.2 software (Waters Corp.).