Dvb car pdms fibre

The extraction of volatiles from the stewed pork was carried out using the manual solid-phase micro-extraction (SPME) equipped with a 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre (Supelco, Inc., Bellefonte, PA, USA). Briefly, 5.0 g of the pork sample was weighed precisely and placed in a 40 mL headspace vial. Immediately after, 1 μL of 2-methyl-3-heptanone was added and sealed tightly with screw caps fitted with a Teflon/silicon septum. The vial was incubated in a thermostatic water bath at 60 °C for 20 min. The selected fibre was used to extract the volatile compounds in head space for 40 min at 60 °C. Upon completion, the fibre was inserted into the injection port (250 °C) of the GC instrument to desorb the analyses for 5 min.

According to the manufacturer’s instructions, the DVB/CAR/PDMS fibre (Supelco, Bellefonte, PA, USA) was exposed to headspace for 40 min to extract volatile organic compounds (VOCs) from fecal samples. VOCs were thermally desorbed by immediately transferring the fiber into the heated injection port (220 °C) of a Clarus 680 (Perkin Elmer, Beaconsfield UK) gas chromatography equipped with an Rtx-WAX column (30 m × 0.25 mm i.d., 0.25 μm film thickness) (Restek) and coupled to a Clarus SQ8MS (Perkin Elmer) with source and transfer line temperatures kept at 250 and 210 °C, respectively. Each chromatogram was analyzed for peak identification using the National Institute of Standard and Technology 2008 (NIST) library. Quantitative data of the identified compounds were obtained by interpolation of the relative areas versus the internal standard area.

The volatile emissions of the wine samples were analysed in triplicate by using Headspace Solid-Phase Microextraction (HS-SPME). For the analysis, 25 mL of each sample was placed in a 50 mL glass flask, covered with aluminium foil, and left to equilibrate for almost 30 min at room temperature. Then, the headspace was sampled for 5 min using a Supelco SPME device equipped with a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre (100 µm, Supelco analytical, Bellefonte, PA, USA), which was preconditioned following the manufacturer’s instructions. Once the sampling time was finished, the fibre was injected into the gas chromatography-mass spectrometry analyses apparatus (Agilent Technologies Inc., Santa Clara, CA, USA) equipped with an Agilent HP-5MS capillary column (30 m × 0.25 mm; coating thickness 0.25 µm) and an Agilent 5977B single quadrupole mass detector. The GC-MS analyses and peak identification were accomplished according to Pieracci et al. [32 (link)].

The volatile compounds from fermenting coffee pulp-bean mass (liquid fraction) were analysed by Solid Phase Microextraction (SPME), using a DVB/CAR/PDMS Fibre (Supelco Co., Bellefonte, PA USA) and injected into gas chromatographer coupled to a mass spectrophotometry connected to an autosampler (GCMS2010 Plus, TQ8040, AO 5000; Shimadzu, Tokyo, Japan). The sample was prepared by diluting two milliliters at 1:1 ratio with distilled water plus NaCl 5% (w/v) and disposed in hermetic sealed vials (20 mL). The SPME fibre was exposed for 30 min at 60 °C. The compounds were thermally desorbed at 260 °C and directly introduced into the gas chromatograph. The GC was equipped with a capillary column (model SH-Rtx-5MS; 30 m × 0.25 mm × 0.25 µm). The temperature within the GC was at follows: column oven at 60 °C, injection at 260 °C, and detector at 250 °C. Helium was the carrier gas used, at a flow rate of 1 mL/min, column press of 57.4 kPa, and split ratio of 1:20. The mass spectrophotometry range was 30–250 (m/z), at an ion source temperature of 250 °C. Volatiles were identified comparing each mass spectrum either with the spectra from authentic compounds or with spectra in reference libraries. The relative abundance of each volatile compound present in the headspace was showed as peak area times 10⁵.

The extraction of VOC from virgin olive oil samples was performed according to Vichi et al. (2003) by means of a Combi-pal autosampler (CTC Analytics, Zwingen, Switzerland) configured for HS-SPME. First, 2 g of olive oil sample was placed into a 10 mL glass vial fitted with a polytetrafluoroethylene (PTFE)/silicone septum (Scharlab, Barcelona, Spain)). Then, the vial was kept at 40 °C under agitation for 10 min, for sample conditioning. After that, a divinylbenzene/carboxen/polymethylsiloxane (DVB/CAR/PDMS) fibre (2 cm length, 50/30 thickness) from Supelco (Bellefonte, PA, USA) was exposed for 30 min to the sample headspace to extract VOC. Finally, the analytes were desorbed by placing the fibre in the gas chromatograph injector port (260 °C) with an SPME injector sleeve (0.75 mm ID) for 10 min, maintaining it for the first 5 min in split-less mode.