Simultaneous Determination of Major Flavonoids in Rat Plasma by a Rapid Resolution LC-ESI–MS Method After Oral Administration of the Flavonoid Fraction of Flos Lonicerae japonicae

A rapid resolution liquid chromatography-tandem mass spectrometric method was developed for the simultaneous analysis of four flavonoids in rat plasma. Key features of this method include a 6.5 min separation by a rapid resolution liquid chromatography system with a 4.6 × 50 mm, 1.8 μm particle size reverse phase column and detection by electrospray ionization tandem mass spectrometric performed in MS–MS mode for multiple reaction monitoring. The developed method was validated with respect to linearity, accuracy, precision and stability and applied for a pharmacokinetic study successfully after oral administration of the flavonoid fraction of Flos Lonicerae japonicae.