Simultaneous Determination of Four Major Volatile Components in Rosemary (Rosmarnus officinalis L.) Leaves by LC-MS/MS with Ultrasonic-Assisted Extraction

Objective:To establish an LC-MS/MS assay for the simultaneous determination of rosmarinic acid,carnosic acid,chlorogenic acid and caffeic acid in rosemary leaves and to optimize conditions for the ultrasonic extraction of these components.Methods: The chromatographic separation was performed on an Agilent Eclipse XDB-C18 column(150 mm × 4.6 mm,5 μm) using a mobile phase consisting of acetonitrile and 0.1% formic acid in water by gradient elution.The analyztes were monitored by ESI-MS/MS in the negative ion MRM mode.The effects of solvent type,solid/liquid ratio,ultrasonic treatment time,pH and acid type on the extraction of rosmarinic acid,carnosic acid,chlorogenic acid and caffeic acid were investigated.Results: Caffeic acid,chlorogenic acid,rosmarinic acid and carnosic acid showed a good linear relationship over the concentration ranges of 0.0005–0.5,0.0005–0.5,0.002–0.2 and 0.01–1 mg/mL,respectively.Under optimal extraction conditions,the contents of rosmarinic acid,carnosic acid,caffeic acid and chlorogenic acid were respectively,4.07,14.50,2.92 mg/g and 8.49 mg/g as determined by the LCMS/MS assay.Conclusion: This array allows rapid,sensitive and simultaneous determination of osmarinic acid,carnosic acid,chlorogenic acid and caffeic acid in rosemary leaves.Their optimal extraction conditions have been established.