Lignin S/G Ratio Determination by Pyrolysis-GC-MS

Pyrolysis coupled with gas chromatography mass spectrometry was used to determine lignin S/G ratio on cell wall residues, as previously described (Tian et al., 2021 (link)). Specifically, sub-samples of ≈ 0.1 mg were pyrolyzed at 650°C for 30 s using the pyroprobe 6200 (CDS Analytical, Oxford, PA) connected to a gas chromatography system (GC-2010 Plus, Shimadzu Scientific Instruments, Columbia, MD) using a Shimadzu SH-Rxi-5Sil MS column (30 m × 0.25 mm ID × 0.25 DF) attached to a mass spectrometer (GCMS-Q P2010) system operated using helium as carrier (1 ml min⁻¹). The chromatograph was operated at a split ratio of 10 and the program was set at 50°C for 1 min followed by ramping to 300°C at 20°C min⁻¹ and finally maintained at 300°C for 10 min. Released products of S and G origin were identified on the basis of their mass spectra using the NIST08 mass spectrum library and quantified from the chromatogram using the peak area.