I’m not seeing GSO here? Is that not EO?
How We Know EO Is Present
Ethyl oleate shows up on GC-MS not as one single clean peak, but as a family of typical fatty acid ethyl esters, especially:
Matching EO markers in your report:
- (E)-9-Octadecenoic acid ethyl ester – 24.93%
→ This is literally ethyl oleate.
- Octadecanoic acid, ethyl ester – 1.33%
→ Ethyl stearate (common EO impurity).
- Ethyl 9-hexadecenoate – 0.75%
→ Ethyl palmitoleate (another EO-related ester).
- 9,12-Octadecadienoic acid ethyl ester (Z,Z) – 3.14%
→ Ethyl linoleate (normal minor component in EO).
Those four peaks are classic EO fingerprints.
EO always contains a mixture of ethyl esters, dominated by ethyl oleate, exactly as shown in your chromatogram.