Mohammad Hadi Meshkatalsadat - Department of Chemistry, Faculty of Basic Sciences University of Technology, Qom, Iran
Meysam Hasheminejad - Department of Chemistry, Faculty of Basic Sciences University of Technology, Qom, Iran
Ali Reza Giasvand - Department of Chemistry, Faculty of Basic Sciences, Lorestan University, Khoram Abad, Iran

This paper is a report of an investigation carried out on gas chromatography–mass spectrometry (GC–MS) following microwave distillation and headspace solid-phase microextraction (MD-HS-SPME) for the analysis of essential oil compounds in dry rosemary leaves (Rosmarinus officinalis L., Lamiaceae). Rosemary leaves are dried before being preserved and used. Using the proposed method, the isolation, extraction and concentration of rosemary leaves essential oil compounds can be carried out in a single step. To demonstrate its feasibility, the MD-HS-SPME was compared with a conventional technique, hydro distillation (HD) for gas chromatography-mass spectrometry (GC-MS) analysis of the essential oil compounds in rosemary leaves. 44 compounds in rosemary leaves were separated and identified by the present method and 36 compounds were separated and identified by HD. The MD-HS-SPME parameters including adsorption time, the amount of added water, microwave power, and irradiation time were studied. The Relative Standard Deviation (R.S.D.) values less than 10% show that the present method has a good precision. The HD method required a long time (3 h) to isolate the essential oil, while MD-HS-SPME needed a little time (only 2 min) to prepare a sample and no organic solvent. These results show that MD-HS-SPME is a simple, rapid and a solvent-free method for determination. Compared with a conventional technique, HD., the advantages of the proposed method are: a short extraction time and high extraction efficiency. All experimental results show that the proposed method is an alternative tool for the fast analysis of essential oils in dryrosemary leaves.

Chromatography–mass Spectrometry; Headspace Solid-phase Micro-ExtractionMicrowave Distillation; Hydrodistillation; Essential Oil; Rosmarinus officinalis L