Gas chromatographic determination of linamarin in bean paste products and imported beans

A gas chromatographic method for linamarin (LI) determination in raw/dried bean pastes was established. The sample was extracted with 80% (v/v) acetonitrile (final concentration) and cleaned up by the use of a macroporous ion-exchange resin column. LI was then converted into the trimethylsilyl derivative, which was determined by using a gas chromatograph with a flame ionization detector. The detection limit by this procedure was LI 0.2μg/g (as hydrogen cyanide) in bean paste. The recovery of LI added at the level of 10 to 100μg/g to a raw/dried sample was more than 91%, and the coefficient of variation was less than 2%. A survey of commercial bean paste by the use of the present method revealed levels of LI (as hydrogen cyanide) of 0.5-2.3μg/g in four of 14 samples.