2.5. GC–MS analysis
The original and microencapsulated sweet orange oil were ana- lysed by using the 6980N/5975 inert GC–MS (Agilent, USA). Before analysis, 1 g original sweet orange oil or its microcapsules were suspended in 10 ml n-hexane:water (1:1) solution. After the mix- ture was sealed and extracted in ultrasonic for 10 min, the solution was allowed to settle and the hexane layer was collected. Then, 5 g of anhydrous sodium sulfate was added to the hexane layer and mixed well. The supernatant was used for GC–MS analysis. The GC–MS conditions were as follows:
Column: HP-5 fused silica capillary
thickness 0.25 lm); carrier gas: helium
temperature 250 °C; detector temperature and type: 300 °C, total ion chromatogram (TIC); programmed column temperature: 69 °C for 1 min, 69–80 °C at 1 °C/min, 80 °C for 2 min, 80–200 °C at 10 °C/min, 200 °C for 1 min, finally 280 °C for 1 min.
(30 m