Figure 2

MS/MS parameters and LC conditions optimization. For each MS/MS parameter optimization, the other normal LC-MS/MS conditions were used, including ion source parameters (collision gas, level 4; curtain gas, 25 psi; Gas 1, 55 psi; Gas 2, 55 psi; ionspray voltage, 5.5 kv; temperature, 550°C) and LC parameters (flow rate, 0.30 mL/min; column oven temperature, 40°C). Finally, the resulting optimized parameters were combined and the signal intensity of the test yakuchinone A (blue open diamond symbol and blue solid diamond symbol) and B (red open circle symbol and red solid circle symbol) were compared with those of data under premature LC-MS/MS conditions.