Application of response surface method for optimization of dispersive liquid–liquid microextraction of water-soluble components of Rosa damascena Mill. essential oil

Dispersive liquid–liquid microextraction (DLLME) coupled with gas chromatography–mass spectrometry (GC–MS) was applied for the determination of Rose water constituents. The effective parameters such as volume of extraction and disperser solvents, temperature, and salt effect were inspected by a full factorial design to identify important parameters and their interactions. It showed that salt addition had no effect on the efficiency. Next, a central composite design was applied to obtain optimum point of the important parameters. The optimal condition was obtained as 37.0 μL for extractor, 0.42 mL for disperser and temperature for 48 °C. The main components that were extracted at the optimum point were benzeneethanol (24.87%), geraniol (23.07%), beta-citronellol (22.38%), nerol (8.48%), eugenol (5.98%) and linalool (5.62%).