The volatilome produced by bacteria during cheese ripening was determined by Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) on 2 g of finely grinded cheese by means of a Combi-Pal automated sampler (CTC Analytics AG, Zwingen, Switzerland) coupled to an Agilent 6890 gas chromatograph with an Agilent 5975 mass spectrometric detector (Agilent Technologies) and a polar column (60 m × 0.25 mm × 10.25 µm, Zebron ZB-WAX plus, Phenomenex, Torrance, CA, USA). Extraction and separation conditions are described elsewhere52 (link). Results are expressed log10 of the peak area (arbitrary units) of the corresponding selected ion.
Combi pal
Manufactured by CTC Analytics
Sourced in Switzerland, United States
The Combi-Pal is a versatile liquid handling and sample preparation workstation designed by CTC Analytics. It can perform automated tasks such as liquid dispensing, mixing, and dilution. The Combi-Pal is a modular system that can be customized to meet specific laboratory requirements.
Automatically generated - may contain errors
Lab products found in correlation
Agilent 5975, by Agilent Technologies (2 mentions)
Agilent 6890, by Agilent Technologies (2 mentions)
Zb wax plus, by Phenomenex (1 mentions)
Nylon syringe filter, by Cytiva (1 mentions)
5975c series, by Agilent Technologies (1 mentions)
7683b series, by Agilent Technologies (1 mentions)
Methanol, by Merck Group (1 mentions)
Db 5ms column, by Agilent Technologies (1 mentions)
Gc 7890a, by Agilent Technologies (1 mentions)
5973n msd, by Agilent Technologies (1 mentions)
Cp 3800, by Agilent Technologies (1 mentions)
7890b gas chromatography system, by Agilent Technologies (1 mentions)
Db waxetr column, by Agilent Technologies (1 mentions)
Dvb car pdms 50 30 μm fiber, by Merck Group (1 mentions)
12 protocols using combi pal
1
Volatile Compounds Profiling of Cheese
2
Chemical Analysis of Organic Solvents in PR Products
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Organic solvents contained in PR products were analyzed after dilution with carbon disulfide (CS2; Kanto, Japan) and methanol (99.8%; Sigma Aldrich, USA). Qualitative analysis was first performed to identify organic solvents in 51 PR products, and further analysis was conducted for quantitation of the identified 20 chemicals. Diluted samples were sonicated for 30 min at room temperature, and viscous chemical samples were filtered through a nylon syringe filter (13 mm, 0.2 μm, Whatman, USA). Qualitative analysis was conducted by gas chromatography (GC, 7890A; Agilent Technology, USA)–mass spectrometry (MS, 5975C Series; Agilent Technology, USA) and auto sampler (Combi PAL, CTC analytics, Switzerland) in scan mode. A DB-5MS column (122-5532; Agilent Technology, USA) was used for analysis. Each mass spectrum was matched up with a GC-MS library (W10N11), and the chemical matching rate selected was higher than 80%.
Then, quantitative analysis was conducted by GC (6890N; Agilent Technology) with a flame ionization detector (FID) and auto sampler (7683B Series; Agilent Technology). The chemical used for quantitative analysis was selected from chemicals detected from the qualitative analysis listed in the MSDS, or if not listed in the MSDS, a chemical known to be toxic was selected. An EN-5 column (053139; SGE Analytical Science, Australia) was used for the analysis.
Then, quantitative analysis was conducted by GC (6890N; Agilent Technology) with a flame ionization detector (FID) and auto sampler (7683B Series; Agilent Technology). The chemical used for quantitative analysis was selected from chemicals detected from the qualitative analysis listed in the MSDS, or if not listed in the MSDS, a chemical known to be toxic was selected. An EN-5 column (053139; SGE Analytical Science, Australia) was used for the analysis.
3
BTEX Degradation Monitoring via SPME-GC-FID
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Aqueous samples (0.3 mL) were collected by syringe through the stoppers, transferred to chromatographic vials and acidified (10 μL of 3 N HCl) for monitoring BTEX degradation periodically by SPME/GC/FID with an autosampler Combi Pal (CTC Analytics) coupled with a gas chromatograph 7890A (Agilent Technologies) equipped with a flame ionization detector. BTEX was absorbed in headspace vials during 10 s with a micro-extraction fiber (SPME, Supelco 75 μm carboxen-PDMS). Desorption time inside the GC injector was 100 s. Compounds were separated through an Optima Wax (Macherey–Nagel) column (30 m × 0.32 mm × 0.50 μm). Helium was used as a carrier gas with a constant flow rate of 1 mL min-1. Results were processed as the residual percentage of BTEX as (Ct/Cc) × 100, where Ct is the hydrocarbon concentration in the microcosm, and Cc the hydrocarbon concentration in the abiotic control microcosm. The resulting values were normalized to o-xylene as an internal standard.
4
Cheese Volatilome Profiling by SPME-GC-MS
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The volatilome produced by bacteria during cheese ripening was determined by Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) on 2 grams of nely grinded cheese by means of a Combi-Pal automated sampler (CTC Analytics AG, Zwingen, Switzerland) coupled to an Agilent 6890 gas chromatograph with an Agilent 5975 mass spectrometric detector (Agilent Technologies) and a polar column (60 m × 0.25 mm × 10.25 µm, Zebron ZB-WAX plus, Phenomenex, Torrance, CA, USA). Extraction and separation conditions are described elsewhere 54 (link) . Results are expressed log 10 of the peak area (arbitrary units) of the corresponding selected ion.
5
GC-MS Analysis of Volatile Compounds
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The GC-MS analyses were performed using an Agilent 6890 gas chromatograph (Palo Alto, CA, USA) equipped with an Agilent MSD5973N mass selective detector, a multifunction automatic sampler (Combi-Pal, CTC Analytics, Zwingen, Swiss) on an HP-1 MS capillary column (100% polydimethylpolysiloxane; 0.2 mm × 50 m; film thickness, 0.33 μm). Samples (1 µL) were injected in split mode (split ratio: 1/100) and the injector was set at a temperature of 250 °C. The carrier gas was helium in constant flow mode at 1 mL/min. The oven temperature was programmed to rise from 40 °C to 220 °C at 2 °C/min, then from 220 °C to 270 °C at 20 °C/min and kept isothermally at 270 °C for 20 min. Acquisition was performed in scan mode (40–400 a.m.u. (atomic mass unit)/s; scan rate: 3.5 scans/s) and mass spectra were generated at 70 eV.
Compound identifications were based on comparison of mass spectra with literature, commercial libraries (Wiley, NIST) and laboratory MS libraries built up from pure substances, combined with comparison of GC linear retention index (LRI) [16 ,17 ,18 (link)]. Retention indices were determined with a series of linear alkanes C6-C28 used as a reference.
Compound identifications were based on comparison of mass spectra with literature, commercial libraries (Wiley, NIST) and laboratory MS libraries built up from pure substances, combined with comparison of GC linear retention index (LRI) [16 ,17 ,18 (link)]. Retention indices were determined with a series of linear alkanes C6-C28 used as a reference.
6
Analysis of N. khasiana Pitcher Volatiles
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N. khasiana pitcher fluids (3 mL each) and 20 mL standard CO2 (carbon dioxide-N5.0, certified concentration 5.49%, nitrogen-N-5.0 balance, Chemtron Science Laboratories, Mumbai, India) bubbled into 3 mL distilled water were transferred to the head space unit (separately) and analyzed by GC/MS/MS. Injection mode: GC head space (Combi Pal, CTC Analytics, Switzerland), syringe temperature 50 °C, sample agitator temperature 60 °C, incubation time 5 min. GC: CP-3800 (Varian, CA, USA), VF-5 (5% phenyl 95% dimethyl polysiloxane, non-polar, 30 m × 0.25 mm i.d., 0.25 μm film thickness) capillary column, column temperature programme isothermal 60 °C for 20 min, flow rate 0.5 mL min−1, MS: Saturn 2200 GC/MS/MS (Varian, CA, USA), mass range 20–60 m/z.
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N. khasiana pitcher fluids (3 mL each) and 20 mL standard CO2 (carbon dioxide-N5.0, certified concentration 5.49%, nitrogen-N-5.0 balance, Chemtron Science Laboratories, Mumbai, India) bubbled into 3 mL distilled water were transferred to the head space unit (separately) and analyzed by GC/MS/MS. Injection mode: GC head space (Combi Pal, CTC Analytics, Switzerland), syringe temperature 50 °C, sample agitator temperature 60 °C, incubation time 5 min. GC: CP-3800 (Varian, CA, USA), VF-5 (5% phenyl 95% dimethyl polysiloxane, non-polar, 30 m × 0.25 mm i.d., 0.25 μm film thickness) capillary column, column temperature programme isothermal 60 °C for 20 min, flow rate 0.5 mL min−1, MS: Saturn 2200 GC/MS/MS (Varian, CA, USA), mass range 20–60 m/z.
7
Measuring Organic Pollutants and Heavy Metals
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Concentrations of OCPs were measured by gas chromatography with an electron capture detector (Gas Chromatography 6890N Agilent Technologies, Santa Clara, CA, USA) equipped with the autosampler Combi-PAL (CTC Analytics AG, Zwingen, Switzerland). Limit of detection (LOD) values for soil and plant samples were 0.1 and 25 µg kg−1, while limit of quantification (LOQ) values were 4.0 and 5.0 µg kg−1, respectively. Quartz sand and cellulose were used as reference samples according to standards ST RK 2131-2011 [50 ] and ST RK 2011-2010 [51 ], used to analyse soil and plant samples, respectively. The TTE concentrations were determined by atomic absorption spectrometry with electrothermal atomisation, using a Varian AA240 Atomic Absorption Spectrometer GTA 120 (Agilent Technologies, Santa Clara, CA, USA). The reference samples were the same as for OCP content, while LOD and LOQ values were 0.1 and 2.0 mg kg−1, respectively. The procedure was described in detail earlier [52 (link)]; briefly, analysis of soil samples was provided according to standards ST RK ISO 11047-2008 [53 ] and GOST 23581.8-79 [54 ]; analysis of plant samples was performed following ST RK ISO 11047-2008 [53 ], GOST 23581.8-79 [54 ], GOST 26930-86 [55 ], and GOST 30178-96 [56 ].
8
Comprehensive VOCs Analysis by GC-MS
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VOCs analysis was performed with a 7890B gas chromatography system (Agilent, Palo Alto, CA, USA) equipped with a CombiPal auto-sampler (CTC Analytics, Zwingen, Switzerland) coupled to an Agilent 5975C triple quadrapole mass detector. The SPME fibre was desorbed into an ultra-inert straight SPME liner (0.75 mm, Agilent Technologies Inc., USA) at 250 °C in splitless mode for 2 min, and separation of compounds achieved through a DB-Waxetr column (60 m × 250 µm inner diameter × 0.25 µm film thickness; Agilent Technologies Ltd., USA) with helium at a flow rate of 1 mL min−1. The oven temperature was set to 40 °C for 3 min and then ramped from 40 to 90 °C at 10 °C min−1, 90 to 180 °C at 5 °C min−1, 180 to 250 °C at 20 °C min−1 and held for 2 min, resulting in a total run time of 31.5 min. The mass spectrometer was operated in an electron impact (EI) ionization at 70 eV with an ion source temperature of 250 °C, to scan a mass range from 35 m/z to 350 m/z.
9
Sulfur Compounds Analysis by GC-SCD
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Analyses were carried out using an Agilent 7890B gas chromatograph with a selective detector SCD 8355. The capillary column was a SPB-1 SULFUR (30 m x 0.32 mm I.D. x 4 µm film thickness (Supelco, Bellefonte PA, USA) preceded by a precolumn, 3 m x 0.32 mm I.D. of fused silica with The injection was made into a MMI injector equipped with an ultra-inert liner of 1 mm I.D. when cryofocusing was used and with an ultra-inert liner of 4 mm i.d. if cryofocusing was not used, both of them from Agilent. The autosampler was a Combi-PAL from CTCAnalytics (Zwingen, Switzerland) with a static headspace unit. After the injection, the syringe was purged with nitrogen for 5 min.
The chromatographic oven was held at 35 °C for 3 min (3.8 min if cryofocusing was used) then heated to 160 °C at 10 °C/min and held at this temperature for 0.5 min. Helium was used as carrier gas at a constant flow rate of 2 mL/min if cryofocusing was used. If not, then the He flow is set first at 0.9 mL/min for 0.8 min and then at 1.4 mL/min for the rest of the program.
The temperature program of CTS 2 was as follows: -150 °C for 0.8 min and then raised at 20 °C/s up to 300°C. Air was used at 50 mL/min as oxidizer gas for the detector, base temperature and burner temperature were 280 °C and 800 °C, respectively. Hydrogen was used also for the detector, the upper flow was 38 mL/min and the lower flow was 7 mL/min.
The chromatographic oven was held at 35 °C for 3 min (3.8 min if cryofocusing was used) then heated to 160 °C at 10 °C/min and held at this temperature for 0.5 min. Helium was used as carrier gas at a constant flow rate of 2 mL/min if cryofocusing was used. If not, then the He flow is set first at 0.9 mL/min for 0.8 min and then at 1.4 mL/min for the rest of the program.
The temperature program of CTS 2 was as follows: -150 °C for 0.8 min and then raised at 20 °C/s up to 300°C. Air was used at 50 mL/min as oxidizer gas for the detector, base temperature and burner temperature were 280 °C and 800 °C, respectively. Hydrogen was used also for the detector, the upper flow was 38 mL/min and the lower flow was 7 mL/min.
10
Stable Isotope Analysis of Junmai-shu
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The δD and δ 18 O values of Junmai-shu were analyzed using an isotope-ratio mass spectrometer (Delta V-Conflo III on-line system; Thermo Fisher Scientific, San Jose, CA, USA) and a high-temperature conversion elemental analyzer (Thermo Fisher Scientific). The analysis was performed according to the procedure described by Gehre and Strauch. 18 The parameters were set as follows: He carrier gas flow rate of 80 mL/min, operating temperature of 1400°C, and column temperature of 80°C. The sample (0.3 μL) was injected into the instrument using an autosampler (Combi-PAL, CTC Analytics, Zwingen, Switzerland). The δD and δ 18 O values were calculated relative to the VSMOW scale with VSMOW and SLAP.
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