2.5 ml syringe

An 8890-gas chromatograph from Agilent Technologies (CA, USA) with a multi-purpose sampler (MPS) operating in headspace mode and a 2.5 mL syringe (Gerstel, Mülheim, Germany) were coupled to a 5977B-quadrupole mass spectrometer with an inert ion source also from Agilent. Chromatographic separation was performed using two in-line Agilent HP-5MS capillary columns (5% diphenyl-95% dimethylpolysiloxane) with 15 m × 0.25 mm I.D. × 0.25 μm, combined with a backflush system setting 0.83 min as post run time.
MassHunter Workstation software (Qualitative Analysis version B.08.00) from Agilent Technologies was used for data acquisition. StatGraphics Plus 5.1 (Statistical Graphics, Rockville, MD, USA), MS-DIAL 4.80 and SIMCA 14.1 (Umetrics, Umeå, Sweden) software were used for the processing of data. The NIST mass spectral library was used for the identification of VOCs.
For the homogenization of honey samples before analysis, an LLG-uniTEXER vortex agitator (Heathrow Scientific, Vernon Hills, Chicago, IL, USA) was used.

The HS-GC-IMS equipment used was an Agilent Technologies 6890N gas chromatograph (Waldbronn, Germany) coupled to an IMS spectrometer from G.A.S (Dortmund, Germany). GC was equipped with a 2.5 mL syringe (Gerstel GmbH, Mühlheim, Germany) for headspace sampling and IMS with a tritium ionization source and a 98 mm length drift tube. Two capillary chromatographic columns from Agilent were tested: one non-polar HP-5MS-UI (5% diphenyl and 95% dimethylpolysiloxan) with 30 m length, 0.25 mm inner diameter, and 0.25 μm of film thickness; and other polar DB-WAX (100% polyethylene glycol) with the same dimensions as the previous one.
GC-IMS data were acquired with LAV version 2.1.1 (G.A.S, Dortmund, Germany). The statistical tools employed for data processing were SIMCA software version 14.1 (Umetrics, Malmö, Suecia), Statgraphics Centurion XV (StatPoint Technologies Inc., Warrenton, VA, USA), QtiPlot software trial version (Iondev Srl, Bucuresti, Rumania) and The Unscrambler X versión 10.4 (CAMO Software, Oslo, Norway).