Agilent db wax column

Crude fat was determined as the sum of ethanol-extractable material, such as waxes, resins, and lipids, according to Sluiter et al. (procedure NREL/TP-510-42619) [21 ]. Samples were extracted with 95% ethanol using a Soxhlet extractor for 16 h. The extract was evaporated to dryness in a weighed flask using a vacuum evaporator at 80 °C and measured gravimetrically.
The fatty acid profile was measured using gas chromatography, according to German Society of Fats Science procedure DGF C-VI 10a (00) + 11f (08) after extraction with petroleum ether [22 ]. In brief, an Agilent DB-WAX column (60 m × 0.32 mm; film thickness: 0.5 μm; Agilent Technologies, Santa Clara, CA, USA) was used. The inner coating of this column consists of highly polar polyethylene glycol. Hydrogen was the carrier gas (0.95 mL min⁻¹). The oven temperature was increased from 100 to 190 °C at a rate of 5 °C min⁻¹ and kept for 14 min. Afterwards, the temperature was elevated to 250 °C at a rate of 5 °C min⁻¹ and maintained constant for another 14 min. The flame ionization detector was operated at 260 °C. The samples (1 μL) were injected in the split mode (50:1). The analytical standards were obtained from Merck.

Each 1 μl of the extracted sample was analyzed by GC-MS operating in a single ion monitoring mode by Shanghai Applied Protein Technology Co., Ltd. In detail, separation and detection were made by Agilent 7890A/5975C system (Agilent) with Agilent DB-WAX column (Agilent, 0.25 μm, 0.25 mm × 30 m). The column temperature program was as follows: (1) 50 °C for 3 min; (2) temperature was gradually elevated to 220 °C in 17 min; and (3) temperature was gradually elevated to 250 °C in 2 min and maintained for 10 min. Helium was used as the carrier gas, and the flow rate was set to 1.0 mL/min. Electron impact ion source (EI) was applied for Mass spectrometry assay. The temperature was set to 280 °C for injection port, 230 °C for ion source, and 250 °C for the Inlet line. QC samples (pooled sample from an equal aliquot of each sample in the experiment) were injected with SIM mode at the beginning of the MS study and after every five injections throughout the experiment, which was used to monitor the MS performance. Finally, the mass data were analyzed by MSD ChemStation to determine the concentration of each compound.

Each 1 μL of extracted samples from brain tissue and plasm was analyzed by GC–MS in a single ion monitoring mode. Briefly, samples were separated and detected by Agilent 7890A/5975C system with Agilent DB‐WAX column (Agilent, 0.25 μm, 0.25 mm × 30 m). The initial column temperature remained at 50°C for 3 min, and then increased to 220°C at 10°C/min, and remained at 220°C for 20 min. Helium was used as the carrier gas, and mass spectrometry assay was performed using the Electron impact ion source (EI). The temperatures of the injection port, transmission line, and ion source were 280, 250, and 230°C, respectively. The stability and repeatability of the system were tested and evaluated through QC (quality‐control) sample in SIM (Selected ion Monitor) scanning mode throughout the experiment. Finally, MSD ChemStation was applied to analyze the mass data to determine the concentration of each compound.⁵²