The
same samples prepared for IC investigation were analyzed by injection
of 5 μL into the ultrahigh-pressure liquid chromatography (UHPLC)
system equipped with photodiode array (PDA) and MS detectors (Accela
1250 and MSQ Plus system, Thermo Scientific). A reversed-phase C18
column (ZORBAX Eclipse Plus RR HD, 2.1 mm × 100 mm, 1.8 μm)
was used at a flow rate of 0.4 mL min–1 with 5.0
mM formic acid in water (solvent A) or acetonitrile (solvent B). The
composition was initially kept constant for 2 min at 5% solvent B,
then reached 100% solvent B over 10 min, and finally remained constant
at 100% solvent B for 4 min. The ESI-MS parameters were as follows:
drying gas temperature, 400 °C; nebulizer voltage, −1.9
kV; cone voltage, −40 V; nebulizer pressure, 70 psi.
same samples prepared for IC investigation were analyzed by injection
of 5 μL into the ultrahigh-pressure liquid chromatography (UHPLC)
system equipped with photodiode array (PDA) and MS detectors (Accela
1250 and MSQ Plus system, Thermo Scientific). A reversed-phase C18
column (ZORBAX Eclipse Plus RR HD, 2.1 mm × 100 mm, 1.8 μm)
was used at a flow rate of 0.4 mL min–1 with 5.0
mM formic acid in water (solvent A) or acetonitrile (solvent B). The
composition was initially kept constant for 2 min at 5% solvent B,
then reached 100% solvent B over 10 min, and finally remained constant
at 100% solvent B for 4 min. The ESI-MS parameters were as follows:
drying gas temperature, 400 °C; nebulizer voltage, −1.9
kV; cone voltage, −40 V; nebulizer pressure, 70 psi.