Sh rxi 5sil ms capillary column

The root exudates were derived by methoxypyridine and N-methyl-N-(trimethylsilyl)trifluoroacetamide. Then, the gas chromatography-mass spectrometry (GC-MS) fingerprints of the root exudates were obtained on a SHIMADZU GCMS-QP2010 instrument (SHIMADZU, Japan). The root exudates were separated on an SH-Rxi-5Sil MS capillary column (221-75954-30, 30 m × 0.25 mm × 0.25 μm, SHIMADZU). The pressure was maintained at 49.5 kPa, giving a column flow of 1 mL/min. The injection volume was 1 μL in splitless mode, and the injector temperature was 250°C. The initial column temperature was 40°C (hold 2 min), and it was increased at a rate of 3°C/min to 80°C and then increased to 260°C at a rate of 5°C/min, at which it was then held for 30 min. The ion source temperature was 230°C with an interface temperature of 250°C. Helium (99.999% purity) was used as the carrier gas at a flow rate of 1 mL/min. Mass spectra were obtained in electron impact (EI) ionization mode at 70 eV by monitoring the full-scan range (m/z 50-500). The compounds were identified by matching the mass spectra obtained with those of the reference compounds stored in the NIST14 library except for the compounds that appeared in the control. The characteristic fragments of the root exudate phenolic acids with more than 80% similarity were compared with those of the phenolic acid standards.

Profiling of SDEE was performed on a Shimadzu GCMS-QP2020 equipped with a Shimadzu AOC-20i Plus auto-injector (Shimadzu Corp., Kyoto, Japan) under electron impact ionization at 70 eV. Separation of components was carried out in SH-Rxi-5Sil MS capillary column with dimensions of 30 m × 0.25 mm ID × 0.25 μm film thickness (Shimadzu Corp., Kyoto, Japan). The initial oven temperature was held at 190°C for 1 min then raised to 300°C at 15°C/min and kept constant for 10 min. Helium was used as the carrier gas with a constant flow rate of 1 mL/min. The injector, MS ion source, and MS interface temperatures were set at 310, 230, and 280°C, respectively. A sample injection of 1 μL was performed in a split mode of 10 : 1 and peaks were detected in full scan acquisition mode from m/z 50 to 500. Identification of the individual components was performed by NIST mass spectral library on the basis of the mass fragment and e/z values of each component. The relative concentration of each peak was computed based on the total ion count.

A Shimadzu GC-2010 Plus system with an AOC-20i Auto-Injector and a GCMS-QP2010 SE ion trap MS system (Shimadzu, Kyoto, Japan) was used for GC-MS analysis using the electron impact ionization mode. Chromatographic separations were performed on a Shimadzu SH-Rxi-5SiL MS capillary column (30 m × 0.25 mm, 0.25mm film thickness; non-polar phase: Crossbond™ 100% dimethyl polysiloxane as stationary phase). The temperatures of the injector and the GC-MS transfer line were 170 and 280 °C, respectively. The carrier gas was ultrahigh purity helium (Airgas); the flow rate was 1.0 mL/min. The mass spectrometer was operated using the following parameters: the ratio of the split injection was 20:1, ionization voltage was 70 eV; ion source temperature was 200 °C; scan mode, 30.0–500.0 (mass range); scan rate, 5000 amu/s, and 3.68 scans/s; start time was 2 min. Electron multiplier (EM) voltage was obtained from autotune. The oven temperature was programmed to hold at 60 °C for 2 min, increase to 300 °C at 50 °C/min, and hold at 300 °C for 3 min.
To measure the residual limonene in LUVs, a 100 μL aliquot is mixed with 1.9 mL of hexane and 50 mg of CaSO₄ (used here to disrupt the LUVs) and stirred for 30 min to extract limonene. The data were averaged from at least three independent measurements.