Detection Of Phytotoxins In Herbal Tea

Herbal tea,which is usually decocted with Chinese herbal medicines,became more and more popular in recent years.With the increasing sales,the quality of herbal tea is getting more and more important.Phytotoxins are kinds of toxic compounds in some plants and might be introduced to herbal tea during the decocted procedure.Given for this,both the China and the European established a series of laws and national standards to limit the residuals of phytotoxins in herbal tea.However,no reverlant literatures about the detection methods of phytotoxins in herbal tea were reported so far.In this paper,by ultilizing high performance liquid chromatography(HPLC)and gas chromatography-mass spectrometry(GC-MS),new methods were established for the simultaneous detection of nine phytotoxins(Protostemonine,Barbaloin,Thujone,Estragole,Pulegone,Safrole,Methyleugenol,Coumarin,?-Asarone,?-Asarone,Santonin)in herbal tea.The residuals of phytotoxins in herbal tea were explored.1.High-performance liquid chromatography method: The herbal tea were purified by HLB solid phase extraction column,concentrated by nitrogen blowing,separated by Welch Ultimate XB-C18(4.6 mm × 150 mm,5 ?m)column,gradient eluted with methanol-ammonium acetate aqueous solution,and detected by HPLC with UV detector.The results showed that the phytotoxins showed linear relationship in the range of the 0.01 ~ 100.0 mg / L with the correlation coefficients higher than 0.99.The detection limit and quantitation limit of the method were 0.2 ~ 6.5 ?g/kg and 0.8 ~ 21.6 ?g/kg,respectively.The average recoveries were ranged from 70% to 104% with the relative standard deviations(n = 6)in the range of 1.08% ~ 5.04%.2.Gas chromatography-mass spectrometry method: Afer centrifuged at high speed centrifuge,the herbal tea samples were purified by HLB solid phase extraction column,elution with acetonitrile,concentrated to 1mL by nitrogen,seperated by DB-5MS Column,and analysed by MS in the selected ion monitoring mode.Under the optimial conditions,the analytes were linear in the mass range of 5 ~ 1000 ?g / L combindign with the correlation coefficients higher than 0.999.The detection limit and quantitation limit of the method were 0.3 ~ 1.4 ?g/kg and 1.0 ~ 4.7 ?g/kg,respectively.the detection limit was,the limit of;The average recoveries of three spiked levels were in the range of 76.3% ~ 99.7% and the relative standard deviations(n = 6)were 2.7% ~ 8.7%.