Evaluation of three headspace sorptive extraction coatings for the determination of volatile terpenes in honey using gas chromatography–mass spectrometry

• Volatile monoterpenes are determined in honey by a simple and solvent-free procedure.
• PDMS proved to be a suitable coating for these analytes using HSSE-TD-GC–MS.
• No practical advantages were observed for other commercial stir bar coatings.
• Levels of volatile monoterpenes in a range of honey samples are given.

Headspace sorptive extraction (HSSE) was used to preconcentrate seven monoterpenes (eucalyptol, linalool, menthol, geraniol, carvacrol, thymol and eugenol) for separation by gas chromatography and mass spectrometry (GC–MS). Three commercially available coatings for the stir bars, namely Polydimethylsiloxane (PDMS), polyacrilate (PA) and Ethylene glycol-silicone (EG-Silicone), were tested, and the influential parameters both in the adsorption and the thermal desorption steps were optimized. PDMS provided the best sensitivity for linalool, geraniol, menthol and eucalyptol, whereas EG-Silicone was best for extracting the phenolic monoterpenes studied. Considering the average obtained slopes from all compounds, PDMS pointed as the best option, and the analytical characteristics for the HSSE-TD-GC–MS method using this coating were obtained. Quantification of the samples was carried out by matrix-matched calibration using a synthetic honey. Detection limits ranged between 0.007 and 0.032 ng g−1, depending on the compound. Twelve honey samples of different floral origins were analyzed using the HSSE-GC–MS method, the analytes being detected at concentrations up to 64 ng g−1.