A headspace-solid-phase microextraction (HS-SPME) followed by GC–FID analysis (Agilent 7820A GC System, Palo Alto, CA, USA) was proposed in this work for the quantification of the hexanal content of chips [42 (link)]. First, 1.00 ± 0.01 g of grounded chips was prepared and then 2 mL of saturated NaCl and 20 µL of the internal standard (4-methyl-2-pentanone, 8 mg kg−1) was added into the SPME vial with a micro-stirring bar. In accordance with the literature, a DVB/CAR/PDMS SPME fiber for the adsorption of polar and nonpolar volatile compounds was used (Supelco, Bellefonte, PA, USA) [43 (link)]. The sample vial was placed in a water bath at 50 °C with a stirring of 500 rpm. First, 10 min of equilibration under these conditions was required. Then, the extraction was carried out during 30 min in which the fiber was exposed before its desorption during 12 min into the GC injector port at 250 °C. The splitless mode was selected in this step. The GC–FID equipment was an Agilent 7820 AGC System (Palo Alto, CA, USA) equipped with a SPB-5 column programmed in two ramps: (a) from 50 °C to 70 °C (hold 1 min) at 5 °C min−1 and (b) from 70 °C to 200 °C (hold 10 min) at 35 °C min−1. The carrier gas was helium at 1 mL min−1 and the FID temperature was 300 °C. Working solutions obtained from an hexanal stock prepared at 30 mg kg−1 in distilled water were used for the external calibration.
7820a gc system
Manufactured by Agilent Technologies
Sourced in United States
The 7820A GC system is a gas chromatograph produced by Agilent Technologies. It is designed for the separation and analysis of complex mixtures of volatile and semi-volatile organic compounds. The system includes a temperature-controlled oven, a sample injection system, and a detector for identifying and quantifying the separated components.
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Lab products found in correlation
Msd 5975, by Agilent Technologies (2 mentions)
5977e msd, by Agilent Technologies (2 mentions)
5975 series msd, by Agilent Technologies (1 mentions)
Avance 3 400 mhz spectrometer, by Bruker (1 mentions)
Openlab cds, by Agilent Technologies (1 mentions)
Supelco 37 component fame mix, by Merck Group (1 mentions)
5973 mass spectrometer, by Hewlett-Packard (1 mentions)
5890 chromatograph, by Hewlett-Packard (1 mentions)
Tr cn100 column, by Teknokroma (1 mentions)
Ezchrom elite, by Agilent Technologies (1 mentions)
Sp 2560, by Merck Group (1 mentions)
Isolera flash purification system, by Biotage (1 mentions)
6890n series gc, by Agilent Technologies (1 mentions)
Agilent 19091j 413, by Agilent Technologies (1 mentions)
Agilent 1260 high performance liquid chromatography system, by Agilent Technologies (1 mentions)
7693a autosampler, by Agilent Technologies (1 mentions)
Db 1ms, by Agilent Technologies (1 mentions)
6520 q tof lc ms mass spectrometer, by Agilent Technologies (1 mentions)
Methanol, by Sinopharm (1 mentions)
Av 400 spectrometer, by Bruker (1 mentions)
51 protocols using 7820a gc system
1
Quantification of Hexanal in Potato Chips
2
Methane Concentration Determination Protocol
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Methane concentrations from porewater samples as well as from glycinebetaine-amended and unamended sediment incubations were determined by GC (Agilent Technologies, 7820A GC Systems) equipped with a packed Porapak Q column and a flame ionization detector. Porewater samples that were stored in 12-mL exetainers got a 3-mL helium headspace, from which 0.5 mL were injected into the gas stream of the GC. Incubation samples that were stored in 6-mL exetainers also got a 3-mL headspace, from which 0.5 mL were injected. The removed gas volume was simultaneously replaced by distilled water. Standard calibration was done by injecting different volumes of calibration gas (100 ppm CH4 in helium, purchased from Air Liquide).
3
Volatile Compound Identification by GC-MS
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Detection and identification of volatile compounds were performed by gas chromatography (Agilent Technologies 7820A GC Systems, Agilent Technologies, Santa Clara, CA, USA) coupled with mass spectrometry (Agilent Technologies 5975 Series MSD, Agilent Technologies, Santa Clara, CA, USA) using a HP-5ms (30 m x 250 μm x 0.25 μm) column.
The program used for the oven was as follows: 50°C for 5 min, 4°C.min -1 between 50°C and 200°C then 10°C.min -1 from 200°C to 270°C, followed by a final step at 270°C for 10 min.
The injector and detector temperatures were set to 250°C and 300°C, respectively. The conditions of the mass spectrometer were mode electronic impact (EI); temperature source 250°C; scanning speed 1 scan.s -1 ; mass acquisition 50-300 uma. The vector gas was H 2 at a 1.5 mL.min -1 flow rate. For identification, mass spectra were compared to the NIST mass spectral library and were confirmed using the retention index and mass spectrum of pure compounds.
The program used for the oven was as follows: 50°C for 5 min, 4°C.min -1 between 50°C and 200°C then 10°C.min -1 from 200°C to 270°C, followed by a final step at 270°C for 10 min.
The injector and detector temperatures were set to 250°C and 300°C, respectively. The conditions of the mass spectrometer were mode electronic impact (EI); temperature source 250°C; scanning speed 1 scan.s -1 ; mass acquisition 50-300 uma. The vector gas was H 2 at a 1.5 mL.min -1 flow rate. For identification, mass spectra were compared to the NIST mass spectral library and were confirmed using the retention index and mass spectrum of pure compounds.
4
Caecal Short-Chain Fatty Acid Analysis
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For each caecal content sample, 0.03 g caecal content was weighed into a 2 mL centrifuge tube, and 400 μL ultrapure water was added. The sample was shaken until homogenized and incubated for 30 min. The samples were centrifuged at 10,000 rpm for 10 min at 4 °C to collect 300 μL of the supernatants. To the supernatants, 30 μL of metaphosphoric acid was added, homogenized by vortexing, and incubated for 3–4 h at 4 °C. Centrifugation was then performed at 13,500 rpm for 15 min at 4 °C to separate the protein and impurities. The supernatant was aspirated, and trans-crotonic acid in a volume equal to the supernatant was added. The mixer was incubated for 20 min, after which a 0.22 μm water phase filter membrane was used to separate the caecal content from the supernatant. The supernatants were stored in 2 mL screw-cap vials. The SCFAs in the caecal content were analyzed by gas chromatography (Agilent Technologies 7820A GC system, Santa Clara, CA, USA) using a 30 mm, 0.25 mm, and 0.33 μm fused silica column (AE-FFAP; ATECH Technologies Co., Ltd., Lanzhou, China) [19 (link)].
5
Analytical Characterization of Organic Compounds
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The GC-MS analyses were performed with a 7820A GC system connected with a mass detector of 5975 series MSD from Agilent Technologies and a nonpolar cross-linked methyl siloxane column with dimensions of 12 in × 0.200 mm × 0.33 µm was used. The 1H and 13C NMR spectra were recorded on a Bruker AVANCE III- 400 MHz spectrometer. 1H NMR spectra were collected at 400 MHz with chemical shift referenced to the residual CHCl3 peak in CDCl3 (δ: H 7.26 ppm). 13C NMR spectra were collected at 100 MHz and referenced to the CDCl3 signal (δ: C 77.0 ppm)46 (link). Only in case of phthalimide the solvent was DMSO-d6, and chemical shifts were referenced to the residual DMSO-d5 peak in DMSO-d6 (δ: H 2.50 ppm) for 1H NMR and the DMSO-d6 peak (δ: C 39.51 ppm) for 13C NMR46 (link). The spectral data of imide products were compared with the literature reports47 (link).
6
Fatty Acid Profiling by GC-FID
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Fatty acid methyl esters (FAME) were analyzed using a 7820A GC System (Agilent Technologies, Santa Clara, CA, USA) fitted with an automatic sampler (Agilent 7693, Santa Clara, CA, USA) and a flame ionization detector (FID) connected to chromatography data system software (OpenLab CDS, Agilent ChemStation, Santa Clara, CA, USA). Separations were performed on SLB-IL 111 columns (100 m × 0.25 mm, 0.2 µm film thickness; Merck KGaA, Darmstadt, Germany), with a constant flow of hydrogen as carrier gas (0.6 mL/min). The temperature gradient was as follows: 40 °C for 4 min, then 50 °C/min to 150 °C; after 30 min 2 °C/min up to 200 °C and maintained for 30 min. Finally, the temperature was raised to 240 °C (ΔT= 4 °C/min) and maintained until the end of the analysis (75 min in total). The FID operated at 250 °C, and the injection port at 300 °C, with a split ratio of 1:80 (1 µL of sample injected). Forty-three FA peaks were identified by comparison with the peaks generated by injection of Supelco 37 Component FAME Mix (Sigma-Aldrich and Nu-Chek Prep Inc., Elysian, MN, USA) and Supelco conjugated (9Z,11E)-linoleic acid (Sigma-Aldrich). The remaining unidentified peaks were labelled using the analytical methods proposed by [30 (link)].
7
Characterizing Winery Byproducts and Yogurt
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Folin–Ciocalteu adapted to a micro-method format was used for the analysis of total phenolic content (TPC) in winery byproduct extracts and yogurt samples [8 ]. A gallic acid calibration curve (0.01–1 mg/mL) was used for quantification. Measurements were performed in triplicate.
In yogurts, total protein was determined by the Kjeldahl method, as defined in Commission Regulation No. 152/2009. Total fat was calculated by gravimetry, as defined in Commission Regulation No. 152/2009. Fatty acid profile was obtained by gas chromatography (Agilent 7820A GC System equipped with Flame Ionization Detector) analyses, calculated according to the ISO 12966-2:2017. Lactose was measured by using the Lactose-D-galactose Assay Kit (Megazyme, Wicklow, Ireland).
In yogurts, total protein was determined by the Kjeldahl method, as defined in Commission Regulation No. 152/2009. Total fat was calculated by gravimetry, as defined in Commission Regulation No. 152/2009. Fatty acid profile was obtained by gas chromatography (Agilent 7820A GC System equipped with Flame Ionization Detector) analyses, calculated according to the ISO 12966-2:2017. Lactose was measured by using the Lactose-D-galactose Assay Kit (Megazyme, Wicklow, Ireland).
8
Monosaccharide Analysis of Bacterial OPS
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The monosaccharides were analyzed as the alditol acetates after hydrolysis of the OPS with 2 M CF3CO2H (120 °C, 2 h) [47 (link)] and acetylated methyl glycosides after methanolysis of the OPS with acetylchloride in methanol (1:10, v/v, 100 °C, 4 h) by GC on an HP-5ms capillary column using an Agilent 7820A GC system and a temperature gradient of 160 °C (1 min) to 290 °C at 7 °C min−1. The absolute configurations of the monosaccharides were determined by GC of the acetylated glycosides with (S)-2-octanol, as described [48 (link)]. GC–MS was performed on a Hewlett Packard 5890 chromatograph (Palo Alto, CA, USA) equipped with a HP-5MS column and connected to a Hewlett Packard 5973 mass spectrometer (Palo Alto, CA, USA).
9
Agilent 7820A GC System for Gas Analysis
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Agilent 7820A GC System for gas analytics was used for qualitative and quantitative analysis of O2 and H2 gases and for faradaic efficiency percentage (FE%) calculations. The gas chromatography system is equipped with two columns (haysepq and molesieve 5A), a flame ionization detector (FID), and a thermal conductivity detector (TCD). Argon was used as carrier gas for all measurements.
10
Greenhouse Gas Flux Measurement Protocol
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The CO2 and N2O fluxes were measured bimonthly from 10:00 am to 12:00 am during the daytime at each site between June and October in 2011, and in May 2012. A sample was taken every 10 min using a 60 mL syringe within 30 min. The CO2 and N2O concentrations were examined by a gas chromatography unit (7820A GC system, Agilent Technologies Inc., Santa Clara CA, USA), equipped with both flame ionization and electron capture detectors in the Laboratory of Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences. Then, the gas fluxes (J) were calculated using the gradient of the time-series of the sampled gas concentrations and the calculation equation as follow [57 (link)]:
where dc/dt is the curve slope of the temporal variation in the gas concentration, M (g mol−1) is the gas molar mass, P (Pa) is the atmospheric pressure at the sampling site, T (K) is the absolute temperature during sampling period, and H (m) is the chamber’s height. V0 (L mol−1), P0 (Pa), and T0 (K) are the gas molar volume, standard pressure, and standard temperature (International Union of Pure and Applied Chemistry), respectively. Flux attributable to a conduit provided by the vegetation, or to the aboveground vegetation itself, was calculated via subtraction for the VBP and VLG sites.
where dc/dt is the curve slope of the temporal variation in the gas concentration, M (g mol−1) is the gas molar mass, P (Pa) is the atmospheric pressure at the sampling site, T (K) is the absolute temperature during sampling period, and H (m) is the chamber’s height. V0 (L mol−1), P0 (Pa), and T0 (K) are the gas molar volume, standard pressure, and standard temperature (International Union of Pure and Applied Chemistry), respectively. Flux attributable to a conduit provided by the vegetation, or to the aboveground vegetation itself, was calculated via subtraction for the VBP and VLG sites.
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