The samples were measured with an Agilent 7820A using hydrogen as a carrier gas (column: CP-Sil 5CB fused silica, 30 m, 1.0 µm, detector: FID, injector temperature: 200 °C, detector temperature: 250 °C, sample volume: 0.4 μL).
Then, 500 mg of each sample was withdrawn with a 100–1000 µL Eppendorf research micropipette, weighed, and then dissolved in 5 mL of N,N-dimethylacetamide. Finally, 70 mg of toluol was added as an internal standard and also weighed. Once fully prepared and dissolved, 1.5 mL of the solution was transferred into an amber glass vial and sealed with a PTFE/silicone septum and measured.
Then, 500 mg of each sample was withdrawn with a 100–1000 µL Eppendorf research micropipette, weighed, and then dissolved in 5 mL of N,N-dimethylacetamide. Finally, 70 mg of toluol was added as an internal standard and also weighed. Once fully prepared and dissolved, 1.5 mL of the solution was transferred into an amber glass vial and sealed with a PTFE/silicone septum and measured.