Abstract: Objective To establish a headspace-gas chromatography method for the determination of residues of benzene, acrylonitrile, methyl methacrylate, toluene, 1, 2-dichloroethane, p-xylene, m-xylene, o-xylene, chlorobenzene, styrene and divinylbenzene in Coleus amboinicus extracts, which is a traditional Chinese medicine (TCM). Methods The samples were balanced by a headspace injector at 85℃ for 45 min, and the split ratio was 10:1 (V : V). The DB-WAX capillary column (30 m long, 0.32 mm wide, and 0.5 μm thick), which was fixed using polyethylene glycol, was used to separate samples, while a flame ionization detector (FID) was used for analysis. Results The eleven volatile organic compounds were well-separated. Experimental results showed that the linearity of these volatile organic compounds ranged from 0.22 μg·mL^-1 to 23.86 μg·mL^-1 with correction coefficients above 0. 99. The limit of quantification was between 0.008 4 μg·mL^-1 and 0.543 2 μg·mL^-1. The average recovery of the target compounds ranged from 84% to 103% at three spike levels, with relative standard deviations less than 10.0% (n=6), which met the requirements of trace determination. Toluene, m-xylene, o-xylene and divinylbenzene were detected in three batches of samples, but below the limit of quantitation and the standard. Conclusion This method is simple, reliable, and applicable to the detection of residual solvents in the extract of Coleus amboinicus, which can facilitate the analysis of residual solvents in other TCM extracts and medication safety.

Key words: Coleus amboinicus, extracts, volatile organic compounds, solvent residues, headspace-gas chromatograph, macroporous resin, quality control, pharmacovigilance