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 (R2 ≥ 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.