Rapid essential oil screening of Rosmarinus officinalis L. by hydrodistillation–headspace solvent microextraction

The hydrodistillation–headspace solvent microextraction (HD–HSME) method was used for preconcentration and identification of the chemical composition of the essential oil of Rosmarinus officinalis L. The effect of extraction solvent, sample mass, microdrop volume and extraction time on HD–HSME efficiency were investigated and optimized. Four solvents were tested; n ‐heptadecane was finally chosen as the extraction solvent and n ‐hexadecane was employed as the internal standard. Two methods (hot and cold) were studied for HD–HSME and compared with hydrodistillation as the reference method. The cold method was found to be superior to the hot method. Thirty‐two compounds were identified, of which α ‐pinene (48.7%), camphene (13.7%), 1,8‐cineole (13.7%), myrcene (4.5%) and camphor (2.7%) were found to be the major constituents. The results were in good correlation with those obtained by the hydrodistillation method.