5977b quadrupole mass spectrometer

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 partition coefficients were determined using static headspace coupled to GC-MS. A capillary DB-5MS column was employed (length: 60 m, internal diameter: 0.25 mm, film thickness: 0.25 μm). Samples were added into glass vials (22.8 mL) under equilibrium conditions at 29 ± 1 °C, and each sample was placed stably to reach thermodynamic equilibrium. A 750-μL sample of headspace was withdrawn using a 2.5-mL thermostatic gastight syringe preheated to 35 °C on a Gerstel autosampling device, and each vial was analysed once. Gas chromatography analyses were carried out on an 8890 coupled to a 5977B quadrupole mass spectrometer (Agilent). Injections were in splitless mode, using a 4 mm i.d. deactivated gooseneck splitless liner transfer. The oven temperature was programmed from 50 °C (for 1 min) to 250 °C (for 1 min) at 20 °C/min. The carrier gas was Helium with a constant flow of 1 mL/min for the column. The mass spectrometer was operated in electron ionisation mode at 70 eV in selected-ion-monitoring mode.

The raw materials of essential oil from Artemisia annua L. were dried using anhydrous sodium sulfite before analysis. About 50 mg of dried oil was weighted and prepared in n-hexane at a 1 mg/mL concentration for sampling. The standard solution of n-alkenes was diluted in n-hexane to obtain a final testing concentration of 50 μg/mL.
An Agilent 8860GC equipped with a 5977B quadrupole mass spectrometer was used for GC-MS analysis. A fused silica HP-5 MS capillary column was used to separate the components. Helium (purity >99.999%) was used as the carrier gas at a constant flow rate of 1.0 mL/min and a split ratio of 10 : 1. The oven temperature was as follows: an initial temperature of 50°C, ramped at 10°C/min to 120°C, at 1°C/min to 135°C, and then at 3°C/min to the final 240°C maintained for 8 min. The injection volume was 1 μL. MS detection was conducted in the electron ionization (EI) mode (70 eV). The ion source, injector, and transfer line temperatures were 230°C, 250°C, and 250°C, respectively. MS analyzer was performed in the full scan mode (m/z 45–650), and the solvent delay time was set at 4 min. MassHunter GC-MS Data Acquisition (Version 10.0) and Qualitative Analysis (Version 10.0) were applied to control the equipment and acquire and treat raw data.