Pyridine

The irradiated and melted samples were evaporated under vacuum inside a vial vessel and analyzed for the presence of saccharides. The measurements were performed using a ITQ 1100 GC–Ion Trap MS system (ThermoScientific, USA), equipped with an Xcalibur MS Platform using a non–polar TG–SQC column (ThermoScientific, USA). 17 μL of hexamethyldisilazane (99% HMDS, CAS 999–97–3, Sigma Aldrich), 6 μL of chlorotrimethylsilane (99% TMCS, CAS 75–77–4, Sigma Aldrich), and 52 μL of pyridine (99.5% anhydrous, Scharlau) were added to the residue as derivatization agents and aprotic solvent, respectively. The vial was then heated at 70 °C for two hours. Subsequently, 0.5 μL of the sample was injected into the chromatograph, and the measurements were performed using a column temperature range of 180–280 °C with a temperature gradient of 30 °C min⁻¹. The mass spectrum was compared with the GC chromatograms and MS spectra of D–forms of ribose, lyxose, xylose (99%), arabinose (98%), threose (60% syrup), ribulose (1 M solution) and xylulose and xylose (98% syrup) standards (all from Sigma Aldrich). Liquid–phase standards (i.e. threose, ribulose and xylulose) were evaporated under vacuum in the presence of phosphorus pentoxide prior to GC–MS analysis.