Hp 5 capillary column

GC-MS analysis was performed with a Varian CP-3800 GC equipped with an HP-5 capillary column (30 m × 0.25 mm; coating thickness 0.25 μm) and a Varian Saturn 2000 ion trap mass detector. Analytical conditions were the following: injector and transfer line temperatures were 220 and 240 °C, respectively; oven temperature was programmed from 60 to 240 °C at 3 °C/min; carrier gas helium was 1 mL/min; 0.2 μL 10% hexane solution was injected; and the split ratio was 1:30. Identification of the constituents was based on comparisons of the retention times with those of authentic standards, comparing their Linear Retention Indices relative to the series of n-hydrocarbons, and it was conducted by computer matching against commercial libraries (NIST 98 and ADAMS 95) and a home-made library of mass spectra built up from pure substances and components of known essential oils and MS literature data. Linear retention indices were calculated using the n-alkanes series (C8–C23) using the Van den Dool and Kratz formula. Moreover, the molecular weights of all identified substances were confirmed by chromatography chemical ionization mass spectrometry (GC-MS), using MeOH as a CI-ionizing gas [42 (link),59 (link)].

GC/EIMS analyses was performed with a Varian CP-3800 GC equipped with a HP-5 capillary column (30 m × 0.25 mm; coating thickness 0.25 μm) and a Varian Saturn 2000 ion trap mass detector. The identification of compounds was done by comparison of their Kovats retention indices (Ri) [determined relative to the tR of n-alkanes (C10–C35)], with either those of the literature and mass spectra of authentic compounds available in our laboratories by means of NIST 02 and Wiley 275 libraries. The components’ relative concentrations were obtained by peak area normalization [18 (link)].

The composition of HEE and its five fractions was determined by Gas Chromatography/Electron Ionization-Mass Spectrometry (GC-EI-MS). Analyses were carried out with a Varian CP-3800 gas chromatograph (Varian Inc., Palo Alto, CA, USA) fitted with an HP-5 capillary column (30 m, 0.25 mm, 0.25 μm film thickness) coupled with a Varian Saturn (Varian Inc., Palo Alto, CA, USA) 2000 ion-trap mass detector. Operating conditions were as follows: injector temperature, 220 °C; transfer line temperature, 240 °C; oven temperature, 60 to 240 °C (set to a 3 °C/min increment), carrier gas: helium at a 1 mL/min flow. After dilution (5%) in HPLC-grade n-hexane, 1 µL was injected in the GC (split ratio 1:30). The acquisition was performed with the following parameters: full scan, with a scan range of 35–300 m/z; scan time: 1.0 s; threshold: 1 count. The identification of the constituents was based on the comparison of their retention times (t_R) with those of pure reference samples and of their linear retention indices (LRIs), which were determined relative to the t_R of a series of n-alkanes (C₉–C₂₅). The mass spectra detected were compared with those listed in the commercial libraries NIST 14 and ADAMS, and in a homemade mass-spectral library, built from pure substances and components of essential oils of known composition and MS literature data [38 ,39 ].

The reactions were stopped by adding 20 μL of 6 M HCl, and an equal volume of ethyl acetate was fully mixed for 1 min to perform the extraction. Then, the mixtures were centrifugated at 1200 rpm for 10 min. The supernatant was used for the GC analysis. GC analysis was performed on Varian 456 Gas chromatograph equipped with HP-5 capillary column (30 m × 0.320 mm × 0.25 μm). The detection conditions were set 2 min at 140 °C, then increased to 220 °C at 15 °C/min and kept at 220 °C for 2 min. The injector temperature was set at 250 °C, the FID detector temperature was set at 280 °C, and the injection volume was 5 µL.

The chemical composition of the essential oils of C. nubigenum and L. angustifolia was analysed by gas chromatography-electron impact mass spectroscopy (GC-EIMS). The analyses were performed with a Varian CP-3800 gas chromatograph, equipped with a HP-5 capillary column (30 m x 0.25 mm; coating thickness 0.25 μm) and a Varian Saturn 2000 ion trap mass detector. Analytical conditions: injector and transfer line temperatures 220°C and 240°C respectively; oven temperature programmed from 60°C to 240°C at 3°C/min; carrier gas helium at 1 mL/min; injection of 0.2 μL (10% hexane solution); split ratio 1:30. Constituents identification was based on comparison of retention times with those of authentic samples, by comparing their LRIs with the series of n-hydrocarbons and using computer matching against commercial (NIST 2014 and Adams 2007) and home-made library mass spectra (built up from pure substances and components of known oils and mass spectra literature data) [39 ; 40 ].

GC-MS analysis was performed with a Varian CP-3800 gas chromatograph equipped with a HP-5 capillary column (30 m × 0.25 mm ID × 0.25 μm film thickness) and a Varian Saturn 2000 ion trap mass detector. Analytical conditions were injector and transfer line temperature 220°C and 240°C, respectively; oven temperature was programmed from 60 to 240°C at 3°C/min. Carrier gas was helium at 1.0 mL/min flow rate. Injection volume was 0.2 μL (10% hexane solution) using a 1 : 30 split ratio. The mass spectrometer was operated at 70-eV ionization voltage. The acquisition mass range was 30 to 300 m/z at 1.0 scan/s.