RP-HPLC simultaneous determination of five triterpenoid acids in different parts of Poria cocos by UV wavelengths switch

To establish a method for simultaneous determination of dehydrotumulosic acid, polyporenic  acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid and pachymic acid in Poria, a RP-HPLC method detected by UV wavelengths switch had been developed, including 210 nm (48−55 min) for pachymic acid and 241 nm (0−48 min) for dehydrotumulosic acid, polyporenic acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid, separately.  The system consisting of a Kromasil C₁₈ column (250 mm × 4.6 mm, 5 μm) and a mixture of acetonitrile and 0.05% phosphate acid as the mobile phase was adopted; The flow rate was 1.0 mL·min⁻¹.  The linear response range was 30.5−610.0 μg·mL⁻¹ (r = 0.999 6) for dehydrotumulosic acid, 12.66−253.2 μg·mL⁻¹  (r = 0.999 5) for polyporenic acid C, 2.99−59.7 μg·mL⁻¹ (r = 0.999 7) for 3-epi-dehydrotumulosic acid, 6.13−122.5 μg·mL⁻¹ (r = 0.999 5) for dehydropachymic acid and 11.3−226.0 μg·mL⁻¹ (r = 0.999 5) for pachymic acid.  The average recoveries of these compounds were 98.5% (RSD = 1.9%), 99.4% (RSD = 1.7%), 97.9% (RSD = 1.2%), 96.7% (RSD = 2.5%) and 97.9% (RSD = 2.3%), respectively.  The method is simple, accurate and reproducible for quality control of Poria.