Two-phase hollow fiber liquid phase microextraction based on magnetofluid for simultaneous determination of Echinacoside, Tubuloside B, Acteoside and Isoacteoside in rat plasma after oral administration of Cistanche salsa extract by high performance liquid chromatography

A new and fast sample preparation technique based on two-phase hollow fiber liquid phase microextraction (HF-LPME) with magnetofluid was developed to quantitate and determine the four phenylethanoid glycosides (PhGs) (Echinacoside, Tubuloside B, Acteoside and Isoacteoside) in plasma after oral administration of Cistanche salsa extract. Analysis was accomplished by reversed-phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection. Parameters that affect the HF-LPME processes, such as the content of magnetic powder, the solvent type, salt content, stirring speed, extraction time and hollow fiber length, were investigated and optimized. Under the optimized conditions, the preconcentration factors for PhGs were higher than 625. The calibration curve for PhGs was linear in the range of 0.1-100ngmL(-1) with correlation coefficients greater than 0.9996. The intra-day and inter-day precision (RSD) were below 8.74% and the limits of detection (LOD) for the four PhGs were 8-15pgmL(-1) (S/N=3). The validated method was successfully applied to separate and determine the four PhGs in rat plasma after oral administration of C. salsa extract.