Simultaneous Identification and Quantification of Canrenone and 11-α-Hydroxy-Canrenone by LC-MS and HPLC-UVD

Figure 2

LC-MS chromatograms of mixed standards (a) and (b) in negative-ion mode. HPLC was performed on a ZORBAX Eclipse XDB-C18 column (150 mm × 4.6 mm, 5 μm) at the column temperature of 30°C. The separation was achieved using the following gradient program: 0–40 min (10%~50% methanol), 40–60 min (50%~100% methanol). The flowrate was at 0.8 mL/min and the sample injection volume was 5.0 μL. Peak assignments: (a) canrenone; (b) 11-α-hydroxy-canrenone. MS spectrograms (A) and (B) stand for the molecular weight of the peak (a) and (b) at 357.44 and 341.40 amu, respectively.