Slb 5ms column

GC-MS analyses of volatile compounds was performed on an SLB-5ms column (30 m in length × 0.25 mm in diameter × 0.25 μm in thickness of film, Merck Life Science, Merck KGaA, Darmstadt, Germany). GC-MS detection involved an electron ionization system that utilized high energy electrons (70 eV). Pure helium gas (99.9%) was used as the carrier gas with a flow rate of 1 mL/min, and an injection volume of 0.7 μL was employed (a split ratio of 5:1). The initial temperature was set at 50 °C and increased up to 350 °C with an increase rate of 3 °C/min and holding time of about 5 min. Relative quantity of the chemical compounds present in each sample was expressed as percentage based on peak area produced in the chromatogram.

The analysis of the volatile fraction was performed on a GC-MS-QP2020 system (Shimadzu, Kyoto, Japan) with an “AOC-20i” system auto-injector. The analyses were carried out on an SLB-5ms column (30 m in length × 0.25 mm in diameter × 0.25 μm in thickness of film, Merck KGaA). The initial temperature was set at 50 °C, afterwards increased up to 350 °C (increase rate: 3 °C/min; holding time: 5 min). GC-MS parameters were as follows: injection temperature: 280 °C; injection volume: 1.0 μL (split ratio: 10:1); pure helium gas (99.9%); linear velocity: 30.0 cm/s; Inlet pressure: 26.7 KPa. EI source temperature: 220 °C; Interface temperature: 250 °C. The acquisition of MS spectra was carried out in full scan mode, in the mass range of 40–660 m/z, with an event time of 0.2 s. Relative quantity of the chemical compounds present in each sample was expressed as percentage based on peak area produced in the GC chromatogram.
Compounds were identified by using the “FFNSC 4.0” (Shimadzu Europa GmbH, Duisburg, Germany), and “W11N17” (Wiley11-Nist17, Wiley, Hoboken, NJ, USA; Mass Finder 3). Each compound was identified applying a MS similarity match and an LRI filter. Linear retention indices (LRI) were calculated by using a C7-C40 saturated alkanes reference mixture (49452-U, MerckKGaA). Data files were collected and processed by using “GCMS Solution” software, ver. 4.50 (Shimadzu).

Lignin composition from twelve biological replicates per inbred line was determined by thioacidolysis based on the original method (Lapierre, 2010 ). Briefly, the thioacidolysis reagent (2.5% (v/v) boron trifluoride diethyletherate, 10% (v/v) ethanethiol in freshly distilled dioxane) was spiked with 4,4′-ethylidenebisphenol (1 mg/mL in dioxane) as an internal standard. Thioacidolysis monomers were extracted after 4 h at 100°C, then silylated with N,O-bis(trimethylsilyl)trifluoroacetamide and pyridine, and quantified by GC/MS [Agilent GC/MS (6890 GC/5975B MS) fitted with a Supelco SLB-5MS column (30 mm × 0.25 mm × 0.25 μm film)] using synthetic thioacidolysis monomers as standards. The linear range and response factor (RF) for the synthetic monomers were: for S, 25–300 μg, r² = 0.998, RF (ion 299 vs. 343 of Bisphenol E) = 2.16; for G, 25–300 μg, r² = 0.998, RF (ion 269 vs. 343 of Bisphenol E) = 2.15; and for H, 2.5–50 μg, r² = 0.998, RF (ion 239 vs. 343 of Bisphenol E) = 2.11.