Floral Scent Compound Extraction in C. praecox

Headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC/MS) were carried out to extract the floral scent compounds in C. praecox. An empty capped vial was used as the negative control. The SPME device was equipped with an SPME fiber (50/30 μm) coated with polydimethylsiloxane (PDMS) (TriPlus 300, Thermo Fisher Scientific, Waltham, MA, USA). In detail, the protocols for HS-SPME followed the methods of Chen et al. [40 (link)]. Subsequently, a GC/MS system (Trace GC Ultra/ITQ900, Thermo Fisher Scientific, Waltham, MA, USA) with an HP-5MS capillary column (30 m × 0.25 mm × 0.25 μm, Agilent J & W Scientific, Santa Clara, CA, USA) was performed to identify the floral volatiles. The variation in the GC oven temperature and the data recorded from the mass spectrometer in electron impact mode (MS/EI) were based on the methods of Li et al. [37 (link)].