Optimization of a headspace solid-phase microextraction method for the gas chromatography-mass spectrometry analysis aroma compounds of Litsea mollis Hemsl. immature fruit

Abstract This study optimized using a headspace solid-phase microextraction (HS-SPME) method for extracting volatile aroma compounds, terpenoids in particular, from Litsea mollis Hemsl. immature fruit (LMIF). Gas chromatography-mass spectrometry was used to separate and identify volatile terpenoids in LMIF. The types of SPME fiber coating, salt addition, and desorption time were optimized by single factor-experiments to determine the range of extraction temperature. Built on insights from the single factor-experiments, the response surface methodology was further used to optimize the extraction temperature, extraction time, and equilibrium time of HS-SPME. The results showed that the optimal HS-SPME conditions for extracting volatile terpenoids from LMIF were: 50/30 μm of DVB/CAR/PDMS SPME fiber, 2.0 g of added sodium chloride, desorption at a temperature of 250 °C for 3 min, extraction and equilibrium temperature of 46 °C, extraction time of 36 min, and equilibrium time of 20 min. Under the above conditions, the predicted value of extraction was 66.92, while the experimental value was 65.78. The prediction value matched well with the experimental value with good repeatability. The designed model was proven to be valid, which can be applied for future extraction of aroma compounds from IMIF.