Objective: To study the uptake status of Guanfu Base I(GFI)in Caco-2 ceils. Method: To establish Liquid Chromotography with Mass Spectrometry(LC-MS) assay

A LC procedure was carried out using an C18(150 mm×2.0 mm

5 μm)and an eluate of 0.2% acetic acid-acetonitrile (30:70)at the flow rate of 0.2 mL·min-1.The MS portion was set with ESI ionsource in the positive ion polarity mode and the selective ion monitoring(SIM).A protonated molecules[M+H] were detected at m/z 388.10 for GFI.The GFI concentrations in Caco-2 cells at various time

concentration

temperature and pH values were measured. Result: The linearity of GFI concentrationcurve was found in the range of 0.2-50.0 μmol·L-1 (r=0.996 7).The minimal detection limit was 0.2 μmol·L-1.The GFI uptakes in Caco-2 cells obeyed a passive diffusion in a time

concentration and pH-dependent manner. Conclusion: This sensitive and specific LC-MS assay can be applied to determine GFI concentrations in Caco-2 cells.