Headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis of the volatile components of longan (Dimocarpus longan Lour.)

Headspace solid-phase microextraction has been applied to the analysis of volatile components in longan (Dimocarpus longan Lour.). Silica fiber coated with divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) was found to be more efficient for extracting volatile compounds than other fibers such as those coated with polydimethylsiloxane, polyacrylate, and carboxen- polydimethylsiloxane. The SPME headspace volatiles were collected using a DVB-CAR-PDMS fiber. The extraction conditions were optimized using a response surface experimental design to analyze the effect of three factors: extraction temperature, equilibrium time and extraction time. The best response was obtained when the extraction temperature was around 50 °C, equilibrium time near 15 min and extraction time close to 25 min. The volatile extracts were analyzed using gas chromatograph/mass spectrometry system. Sixty-two different volatile compounds from the headspace of longan were identified. The linearity was good in the considered concentration ranges (R 2 ≥ 0.965). Average recoveries ranged from 78.6 to 108.3% and showed good accuracy. The precision of the present method was found to be good (RSD < 13.59%). Therefore, this method can be applied to determine the quality of the longan or other volatile components as an alternative to full-scale headspace analysis. © 2009 Springer-Verlag.