G4513a autosampler

Volatile analysis was performed on a 7820A GC coupled to a 5777B single quad mass selective detector (Agilent Technologies, Cheadle, UK). The gas chromatograph was fitted with a non-polar HP5-MS capillary column (with 30 m × 0.25 mm × 0.25 μm film thickness) coated with (5%-phenyl)-methylpolysiloxane (Agilent Technologies, Santa Clara, CA, USA) and used hydrogen carrier gas at a constant flow rate of 1.2 mL min−1. Automated injections of 1 μL each were made using a G4513A autosampler (Agilent Technologies, Santa Clara, CA, USA) in splitless mode (285 °C), with oven temperature programmed at 35 °C for 5 min then at 10 °C min−1 to 285 °C. Identification of compounds was carried out according to their mass spectra, linear retention index relative to retention time of n-alkanes, and co-chromatography with authentic compounds [22 (link)].

Twenty milligrams of dried Arabidopsis seeds were collected from ten plants, comprising three replicates. We followed the extraction protocol for FAs and the preparation of FA methyl esters as described previously [52 (link)]. FA analyzed by using a gas chromatograph-mass spectrometer (GC68990N/MS5937, Aglient Technologies, Santa Clara, CA, USA) equipped with a G4513A autosampler (Agilent). The column was an aryl-polysiloxane packed capillary column (HP-88; 30 m × 0.25 mm i.d., 0.20 µm film thickness; Agilent). Qualitative FA analysis was achieved by a mass spectra database search (NIST08 Library) and co-elution with corresponding standards. A standard curve method with an internal standard was used as the quantitative approach to construct five calibration plots of analyte/internal standard peak-area ratio versus standard concentration, as determined by the least squares method. The FAMEs in each sample were measured using methyl heptadecanoate as the internal standard. The FAMEs were expressed as milligrams per gram dry weight (DW) of sample. All samples were analyzed in triplicate under the same conditions.

Analyses were carried out on a 7820A GC coupled to a 5977B single quad mass selective detector (Agilent Technologies, Cheadle, UK). The GC was fitted with a non-polar HP5-MS capillary column (30 m × 0.25 mm × 0.25 μm film thickness) coated with (5%-phenyl)-methylpolysiloxane (Agilent Technologies) and used hydrogen carrier gas at a constant flow rate of 1.2 ml/min. Automated injections of 1 μl were made using a G4513A autosampler (Agilent Technologies) in splitless mode (285°C), with oven temperature programmed from 35°C for 5 min then at 10°C/min to 285°C. Compounds were identified according to their mass spectrum, linear retention index relative to retention times of n-alkanes, and co-chromatography with authentic compounds.

Analyses were carried out on a 7820A GC coupled to a 5977B single quad mass selective detector (Agilent Technologies, Cheadle, UK). The GC was fitted with a non-polar HP5-MS capillary column (30 mm x 0.25 mm x 0.25 µm film thickness) coated with (5%-Phenyl)-methylpolysiloxane (Agilent Technologies) and used hydrogen carrier gas at a constant flow rate of 1.2 ml/min. Automated injections of 1 µl were made using a G4513A autosampler (Agilent Technologies) in splitless mode (285 °C), with oven temperature programmed from 35 °C to 5 min then at 10 °C/min to 285 °C. Compounds were identified according to their mass spectrum, linear retention index relative to retention times of n-alkanes, and co-chromatography with authentic compounds.

Isothiocyanates were extracted by using 800 μl of the above waste water samples. To verify the quality of the extraction to each sample 400 μl of a 1.74 mM ethylisothiocyanate solution in milliQ water was added as internal standard. To extract the isothiocyanates from the water, 200 μl of dichloromethane (DCM) was added, the mixed sample was vortexed, briefly centrifuged at 10000 rpm and 100 μl of the DCM phase was taken for GC-TOF-MS analyses on a JEOL AccuTOF-GCv JMS-100GCv equipped with an Agilent 7890A GC with a HP-5MS column (30 m × 0.25 mm × 0.25 μm) and a G4513A autosampler. Conditions used for the GC-TOF-MS isothiocyanate analyses: 50°C for 1 min, followed by a temperature gradient of 30°C/min to 200°C. Split ratio: 1:10. Detector voltage 2000 V. Injection volume 1 μl. An external MeITC reference curve (5–20 nmol/microliter) was used for quantification.

Volatile analysis was carried out on a 7820A GC coupled to a 5977B single quad mass selective detector (Agilent Technologies, Cheadle, UK). The gas chromatograph was fitted with a non‐polar HP5‐MS capillary column (30 m × 0.25 mm × 0.25 μm film thickness) coated with (5%‐phenyl)‐methylpolysiloxane (Agilent Technologies) and used hydrogen carrier gas at a constant flow rate of 1.2 mL min⁻¹. Automated injections of 1 μL were made using a G4513A autosampler (Agilent Technologies) in splitless mode (285 °C), with oven temperature programmed from 35 °C for 5 min then at 10°C min⁻¹ to 285 °C. Compounds were identified according to their mass spectrum, linear retention index relative to retention times of n‐alkanes, and co‐chromatography with authentic compounds.

A heptane assay method has been developed using GC-FID in order to quickly check heptane content in samples. A calibration curve with fossil heptane in hexane at five chosen concentrations (0%; 20%; 40%; 60%; 80% m/m) was performed with linear regression (Figure S2, Supplementary Information).
Heptane assays by GC/FID were performed on an Agilent Intuvo 9000 chromatograph with a G4513A autosampler equipped with a flame ionization detector (temperature set at 250 °C, air flow at 300 mL/min, H2 flow at 30 mL/min). The column used is an apolar column HP-5 MS 30 m × 0.25 mm × 0.25 μm, with H2 as carrier gas set at 1 mL/min. A 0.1 µL volume injection volume was used, with a split ratio of 1/100. Temperature program mode was used for the oven: 1 °C/min from 40 °C to 50 °C and then 20 °C/min up to 270 °C, followed by 20 min at 270 °C.