Determination of 24 Trace Aromatic Substances in Rosemary Hydrosol by Dispersed Liquid–Liquid Microextraction–Gas Chromatography

Abstract

A combined dispersed liquid–liquid microextraction (DLLME) and chromatography (GC) method was developed for the determination of 24 aromatic substances in rosemary hydrosol in this work. The pretreatment method of DLLME was optimized by carefully selecting the appropriate extraction agents, dispersants, and their respective amounts. With carbon tetrachloride as the extractant and acetone as the dispersant, the enrichment factor of DLLME is 13.3, and the 24 target substances such as eucalyptol, camphor and verbenone can be separated within 31 min and quantified by an external standard method using gas chromatography (GC). The correlation coefficient r2 of the linear regression equation is within the range of 0.9983 to 0.9991. The detection limit of the method was 0.02 mg/L, the recovery rate of the spiked solution was 76.4–118.4%, the relative standard deviation was 0.4–6.9% and the method was used to detect the semi-finished products of rosemary hydrosol and the finished rosemary hydrosol sold on the market. This method also provides a reference for the qualitative and quantitative determination of aromatic substances in other hydrosols.