Rapid determination of two triterpenoid acids in Chaenomelis Fructus using supercritical fluid extraction on-line coupled with supercritical fluid chromatography

In this study, an on-line supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) method was developed for the rapid determination of oleanoic acid and ursolic acid in Chaenomelis Fructus. After optimization of the conditions, the two triterpenoid acids was obtained by SFE using 20% methanol as a modifier at 35°C in 8 min. They were resolved on a Shim-pack UC-X Diol column (4.6 × 150 mm, 3 μm) in 14 min (0 - 10 min, 5 - 10%; 10 - 14 min, 10% methanol in CO ₂ ) with a backpressure of 15 MPa at 40°C. The on-line SFE-SFC method could be completed within 40 min (10.79 mg/g dry plant, R _s = 2.36), while the ultrasound-assisted extraction and HPLC method required at least 90 min (3.55 mg/g dry plant, R _s = 1.92). This on-line SFE-SFC method is powerful to simplify the pre-processing and quantitative analysis of natural products.