Development of gas chromatography–mass spectrometry with microwave distillation and simultaneous solid-phase microextraction for rapid determination of volatile constituents in ginger

In this study, gas chromatography–mass spectrometry (GC–MS) following microwave distillation and solid-phase microextraction (MD–SPME) was developed for the analysis of essential oil compounds in fresh ginger. In the proposed method, the isolation, extraction and concentration of volatile components in ginger were carried out in one single step, using the MD–SPME technique, and the analytes on the SPME fiber were analyzed by GC–MS. Some parameters, including SPME fiber coating, microwave power and irradiation time, were optimized. The optimal experiment parameters obtained were: 65 μm PDMS/DVB SPME fiber, a microwave power of 400 W and an irradiation time of 2 min. To demonstrate its feasibility, MD–SPME was compared with conventional SPME for the extraction of essential oil compounds in fresh ginger. Using MD–SPME followed by GC–MS, 54 compounds were separated and identified in ginger, which mainly included geranial (5.25%), zingiberene (15.48%), β-sesquiphellandrene (5.54%) and β-phellandrene (22.84%), whereas only 39 compounds were separated and identified by conventional SPME followed by GC–MS. The relative standard deviation (R.S.D.) values of less than 10% show that the proposed method has good repeatability. The result show that MD–SPME, followed by GC–MS, is a simple, rapid, solvent-free method for the determination of volatile compounds in ginger.