Rapid Extraction Method of Quantitating the Lachrymatory Factor of Onion Using Gas Chromatography

A rapid extraction method has been developed for the quantitation of ( Z, E )-propanethial S -oxide, the lachrymatory factor (LF), and other flavor chemicals in onion ( Allium cepa ) using gas chromatography. This method involves crushing the onion and extracting the resulting juice with a solution of methylene chloride and an internal standard. The resulting extract is concentrated and injected onto a gas chromatograph. This method is shown to be simple, fast, and reproducible. Results show that onion juice contains 1−22 μmol of the LF/mL.