Agilent 8890 gc system

For the analysis of volatiles, headspace solid-phase micro-extraction (HS-SPME) (PAL RSI 120 autosampler, CTC Analytics, Switzerland) was coupled to GC–MS analysis (Agilent 8890 GC system, Agilent Technologies) [28 ]. Approximately 5 mL sample was immediately processed after collection. First, it was filled into a vial, supplemented with 1 g NaCl, and incubated for 20 min at 40 °C, and 400 rpm). Afterwards, an SPME fibre (65 µm, divinylbenzene/polydimethylsiloxane, preconditioned for 1 h at 260 °C, Agilent Technologies) was exposed to the headspace of the vial for 20 min to absorb the volatiles. Then, the fibre was placed into the GC–MS injector (300 °C, 3 min) for desorption [28 ]. The volatiles were then separated on an HP-5MS column (30 m, 0.250 mm, 0.25 µm, Agilent Technologies), using helium as carrier gas (0.4 mL min⁻¹). Chromatograms were recorded by monitoring the total ion current (TIC) over a mass range from 30 to 300 m/z. Following deconvolution of the obtained signals (Agilent Chemstation, Agilent Technologies), individual analytes were identified through mass spectra library search (NIST/EPA/NIH Mass Spectral Library 08). The corresponding area counts for each compound were collected for quantification. Measurements were conducted in triplicate.

Beer samples (10 mL) were transferred into 20 mL vials and 1 g of sodium chloride and 0.5 mL of internal standard iso-butanol were added. The samples were analysed by gas chromatography (Agilent 8890 GC System; Agilent, USA) coupled with mass spectrometry (597BB GC/MS; Agilent, USA) using a system equipped with an autosampler (PAL RSI 120). Agilent MSD ChemStation Enhanced Data Analysis (Rev. F.01.036.2357) was used for data analysis. The parameters and operating conditions are listed in Table 1, following the method described by Dennenlöhr et al. [17 (link)].
Calibration curves with eight calibration points were constructed for myrcene, linalool, alpha-terpineol, beta-citronellol, nerol, geraniol, geranyl acetate, beta-caryophyllene, alpha-humulene and caryophyllene oxide. The obtained correlation coefficients were more than 0.99 and the relative standard deviations (RSDs) were up to ±16%.

The flavor compound was detected using a gas chromatography–mass spectrometer (GC-MS; Agilent 8890 GC system-Agilent 5677B MSD, Agilent Technologies). The specimens were prepared by following the protocol employed in our previous study using Headspace-Solid Phase Microextraction (HS-SPME).⁵³ First of all, volatile and semivolatile compounds from the samples were adsorbed to the carboxen/polydimethylsiloxane/divinylbenzene (CAR/PDMS/DVB) fibers for 40 min. Then, the fibers were injected to the GC-MS with split (20:1) mode. The inlet temperature was 250 °C whereas the temperature of the column oven was remained at 40 °C for the first 5 min and rasied to 240 °C at the raise speed of 4 °C/min. The column oven temperature was then remained at 240 °C for 20 min for analysis.
Thereafter, the specific flavors were assigned to each detected compound based on the flavor information obtained from the Flavor Extract Manufacturers Association of the United States (FEMA; https://www.femaflavor.org/flavor-library) lists and the Good Scents Company (TGSC) information system (https://www.thegoodscentscompany.com/).