Tandem gas chromatography‐mass spectrometry analysis of volatiles from soybean oil

A time vs. volatile decomposition study was made on commercially available soybean oil aged under normal laboratory room conditions. Samples were taken at weekly intervals for peroxide value (PV) determinations, organoleptic evaluations and volatile analyses. Volatiles, stripped from the oil samples in an all‐glass system devoid of connecting joints, were collected and sealed in attached capillary tubes. The encapsulated compounds were introduced into a tandem gas chromatograph‐mass spectrometer via a capillary crusher. All collections, transfers or introductions of volatiles were performed without the aid of solvents. Hydrocarbons and, subsequently, aldehydes were the principle volatiles associated with the initial and intermediate stages of soybean oil autoxidation (PV 0–11). A variety of other compounds were also found as the level of autoxidation increased. Identified compounds, PV's and organoleptic evaluations are correlated.