Hp6890 gc

HS-SPME-GC-MS was carried out using the method of Duval et al. (2013) (link). Five ml of 1-month old wine was placed in a 20 ml sealed headspace vial (Supelco, Bellefonte, PA, USA). Headspace vials were then placed in the agitator/incubator of an automatic headspace sampler (GERSTEL MPS 2, Gerstel Inc., Mülheim an der Ruhr, Germany) and incubated at 70°C for 10 min (incubation time) in order to promote volatile compounds in the headspace. Extractions were performed by immersing a DVB–CAR–PDMS fiber in the headspace for 60 min (extraction time). After each extraction, the extracted compounds were desorbed at 260°C for 7 min in the injection port of an HP 6890GC equipped with an MSD 5973 mass detector (Agilent Technologies, Palo Alto, CA, USA). Calibration solutions were processed in the same way using 5 ml of the wine matrix mixed with target compounds. Volatile compounds (eugenol, guaiacol, furfural, vanillin, cis-, and trans-whisky lactone) were purchased from Sigma–Aldrich and used as received. We used 3,4-dimethylphenol as the internal standard at 10 mg/l in each sample. Using highly aroma-concentrated calibration samples either alone or in mixture, we checked that there were no competition effects for the fiber between aromas. Chromatographic analyses were performed in biological triplicate and technical duplicate.

In the case of the THMFP measurement, the raw wastewater and treated wastewater samples were examined following the standard methods 5710 B, 4500-Cl B, and 6232 B [18 ]. The formation potential of the THMs was analyzed for chloroform (CHCl₃), bromodichloromethane (CHBrCl₂), dibromochloromethane (CHBr₂Cl), and bromoform (CHBr₃). The THMFP measurement consisted of three steps: (1) a free chlorine residual measurement, (2) liquid–liquid extraction, and (3) sample analysis. Firstly, the THMFP test was conducted for 7 days. At the end of the 7-day reaction period, samples had a remaining free chlorine residual of 3–5 mg/L. The residual chlorine was measured using a portable spectrophotometer (HACH, DR/890 colorimeter) before proceeding to the next step. Pentene was used as the solvent. The extracted solution was kept in a refrigerator under 4 °C. Finally, the extracted solution was taken and analyzed using gas chromatography (GC-ECD) (Hewlett Packard, HP 6890 GC, Agilent Technologies, Inc., Santa Clara, CA, USA) with an RTX-624 column.

To characterize and separate the trapped metabolites from urine and breath, we used a gas chromatograph coupled to a mass spectrometer (GC–MS; HP 6890 GC and 5975 MS; Agilent Technologies, Palo Alto, CA, United States) in the electron impact at 70 eV. Helium was used as the carrier gas at an average linear flow rate of 35 cm/s. An autosampler (Agilent Technologies) was used to inject 1 μl of each sample into the GC–MS on a non-polar capillary HP-5 column. Injections of the volatile extracts were conducted in a splitless injector at 220°C. The oven temperature was programmed to 35°C for 5 min and then increased by 10°C/min to a final temperature of 280°C and held at this temperature for 10 min. Mass spectra and retention times of volatiles were compared with their commercial standards where available and library database spectra using the NIST mass spectral program (ver. 2.0), Pherobase¹, and the NIST web book². We placed emphasis on metabolites that were induced or enhanced when compared to the healthy cow urine and breath. When the potential biomarker compounds were available, we co-injected the standards and compared their spectra and retention times of the predicted compounds to confirm their identities.

GC/O analyses were performed on an HP6890 GC (Agilent Technologies, Santa Clara, CA, USA) equipped with a DB-5 column (30 m × 0.25 mm i.d. × 0.25 µm film thickness (Agilent Technologies)) coupled with a 5973 MS (Agilent Technologies) operated in electron impact mode as similarly described by Moskowitz et al. [13 (link)]. The system was also equipped with an olfactometry port (Gerstel, Mülheim an der Ruhr, Germany). The effluent was divided 1:1 between the MS and the olfactometry port. The GC conditions were as follows: 0.5 µL sample was injected via air sandwich technique into the inlet which was held at 250 °C set to splitless mode, helium carrier gas was at a constant pressure of 180 kPa. The GC oven temperature program was as follows: initial conditions 40 °C held for 2 min, followed by a 7 °C/min ramp until 250 °C, which was held for 10 min. Each sample was diluted by half-volume in dichloromethane until the dilution had been carried out to a concentration of 128th of the original extraction had been achieved. The largest dilution at which each compound was detected was defined as the FD value. Each dilution was analyzed in triplicate by two panelists. Compound identification was performed using mass spectral data, odor descriptors, and the linear retention index (LRI) of the authentic compound. LRI values were calculated using an n-alkane ladder.

Metabolites were routinely extracted from finely milled tomato powder using methanol, with ribitol as an internal standard for relative quantification, and derivatized as described in Enfissi et al. (2010). GC‐MS analysis was carried out on an Agilent HP6890 GC with a 5973MSD as described in Enfissi et al. (2010) and components identified using a mass spectral (MS) library constructed from in‐house standards as well as the NIST 98 mass spectral library.

Samples consisting of ten seeds each were ground to a powder using a small mortar and pestle under liquid nitrogen. Fatty acid methyl esters (FAMEs) of a subsample from each seed pool were prepared by acid methanolysis (Burkey et al. 2007 (link)). Frozen and ground seed tissue was heated to and held at 85 °C for 90 min in a 5 % HCl–95 % methanol solution. FAMEs were partitioned two times into hexane and transferred to 2-ml vials for analysis. The FAMEs were separated by gas chromatography using an HP 6890 GC (Agilent Technologies, Inc., Wilmington, DE) equipped with a DB-23 30 × 0.53 mm column (Agilent Technologies, Inc.). Operating conditions were 1-µl injection volume, a 20:1 split ratio, and He carrier gas flow of 6 ml min⁻¹. Temperatures were 250, 200, and 275 °C for the injector, oven, and flame ionization detector, respectively. Peak areas of the chromatograms were analyzed using HP ChemStation software. Fatty acid contents, as percentages, were calculated as mg fatty acid g⁻¹ oil.