GC determination of linoleic acid in Solanum Lyratum Thunb from different habitats

Objective:To develop a GC method for the determination of linoleic acid in Solanum Lyratum Thunb. Methods:Solanum Lyratum Thunb was extracted with chloroform by heating reflux.Then,samples were saponified, esterified,extracted with n-hexane and determined by GC.The chromatographic analysis was performed using HP -5 capillary column(30 m×0.25 mm×0.25 μm)with FID detector.Highly pure N_2 was used as carrier gas.The column temperature was programmed from 150℃(held for 1 min)to 225℃ at a rate of 15℃·min~(-1),then to 260℃(held 3 min)at a rate of 5℃·min~(-1).Results:Methyl linoleate was separated well with other components. There was a good linear relationship within the concentration range of 0.02-0.14 mg·mL~(-1)(r=0.9997).The average recoveries(n=3)of linoleic acid at high,middle and low concentration were 96.5%(RSD=1.9%), 96.4%(RSD=1.3%)and 95.6%(RSD=1.8%)respectively.Conclusions:The method is simple,rapid,accu- rate and reproducible.It is suitable for the determination of linoleic acid in traditional Chinese herbs.