Use of an autosampler for dynamic headspace extraction of volatile compounds from grains and effect of added water on the extraction

An autosampler attached to a purge and trap instrument was used to aid rout ine analyses of grain samples for volatile compounds associated with off-od ors. Trapped volatiles were transferred to a gas chromatograph/mass spectro meter instrument for separation and detection. Dynamic extraction of volati les from similar to 18 g of whole grain at 80 degrees C was accomplished by purging helium through a sample vial with a Teflon-lined septum on each en d. The autosampler automatically added internal standard to the sample befo re purging began, which required the addition of 1 mL of water for complete transfer of the standard to the sample. The added water enhanced extractio n of 1-octen-3-ol, 1-octen-3-one, and some other compounds from soybeans bu t-not from starchy grains such as corn and wheat. Addition of a free radica l scavenger, such as citric acid, greatly diminished the recovery of 1-octe n-3-ol and 1-octen-3-one from soybeans.