Rapid analysis of the essential oil components of dried Perilla frutescens (L.) by magnetic nanoparticle-assisted microwave distillation and simultaneous headspace solid-phase microextraction followed by gas chromatography-mass spectrometry.

In this work, two solvent-free sample preparation techniques of microwave distillation (MD) and headspace (HS) solid-phase microextraction (SPME) were combined, and developed for the determination of essential oil compounds in dry traditional Chinese medicine (TCM). Amine-functionalized magnetite nanoparticles (AMNs) were added and mixed with the dried Perilla frutescens (L.) sample, which was used as a microwave absorption solid medium for dry distillation of the TCM. Using the proposed method, isolation, extraction and concentration of TCM essential oil compounds can be carried out in a single step. The AMN-assisted MD-HS-SPME parameters including fiber coating, microwave power, irradiation time, and the amount of added AMN were studied. The optimal analytical conditions were: fiber coating of 100 µm PDMS/DVB, microwave power of 230 W, irradiation time of 2 min, as well as the addition of 0.1 g AMN to the TCM sample. The proposed method is applied to the determination of essential oil in Perilla frutescens (L.) and the RSD values is less than 9%. To demonstrate the method feasibility, the conventional HS-SPME method was also used for the analysis of essential oil in the TCM. Experimental results show that more compounds were isolated and identified by AMN-assisted MD-HS-SPME than those by HS-SPME. It was found that the proposed method is an alternative tool for the fast analysis of essential oils in dry TCMs.