The Determination Of The Trace Elements In Tea Leaves By ICP-AES、ICP-MS、AFS、IC

Tea leaves(Latine name: Camellia sinensis(L.)O.Kuntze),which has broadeffects,belonging to dicotyledonous plants.The function of the tea leavesincludes:anti-fatigue,anti-aging,antibacerial,anti-inflammatory, resistance toradiation,drop hematic fat, blood sugar and blood pressure.prevention of cancer anddental caries;enhance immunity,and can also help to lose weight.This study appliedinductively coupled plasma emission spectroscopy (ICP-AES), atomic fluorescencespectrometer (AFS), ion chromatography (IC) and inductively coupled plasma massspectrometry (ICP-MS) and other modern means to study on the microelement in thetea leaves samples.The study contains the following five mian parts：1. After processing the tea leaves sample by microwave digestiontechnology,and studying on the digestion condition,use ICP-AES(standard injectionsystem) to determin the trace element in four types(incluidng19kinds) of tealeaves.The element can be detected including Al (aluminum), B (boron), Ba (barium),Ca (calcium), Cu (copper), Fe (iron), K (potassium), Mg (magnesium), Mn(manganese, Na (sodium), Ni (nickel), P (phosphorus), Pb (lead), S (sulphur), Si(soluble silicon), Sr (strontium), Ti (titanium), zinc (Zn).The linear correlationcoefficient of these18elements are in the range of0.9993~0.9999,and the recoveriesare in the range of87.8%~109.0%.The high contents of these element are Al、Ca、K、 Mg、Mn、P、S；Fe、Na、Si、Zn;The less contents are B、Ba、Cu、Ni、Sr、Ti;Thetea sampel almost contains no Pb except individual one.2. Use the boiling high pure water to saok the tea leaves,the solution getted arewithout digestion,then use the ICP-AES HF durable injection system to determin theeight element(Al、Ca、K、Mg、Mn、Na、P、Zn) in the solution.After that,we canget the result of the detected elements’contents.The result of using this method todetermin the element are match when comparing with the method that digest solutionwith acid and use standard injection system.the method established can reduce thepretreatment steps,and it is more accord with the reality that people dringking tea,andthe results geteed are more meaningful.3. Use microwave technology to processe the tea leaves samples,apply ICP-MSto determin three low content elements(As、Cd、Pb).after analyzing the result,we canfind the the contents of As in tea leaves are above100μg/kg,some are a few hundred-s μg/kg;the contents of Cd are in the range of dozens of μg/kg,some and out of100μg/kg;comparing with As and Cd, the contents of Pb are higher,most of the samplesare out of1mg/kg. the contents of As、Pb in most of the tea leaves are in the range of<GB2726-2005contaminants in food limited> that permitted,but the content of Cd inmost of tea leaves are exceed.4. Use microwave technology to process the tea leaves sampels,then apply theHG-AFS to determin the contents of Se and Hg under the given experiementcondition.The result demonstrate,the contents of Se in the tea leaves are in the rangeof <GB2726-2005contaminants in food limited> that permitted,but the content of Hgin tea leaves are exceed.5.Adopt the method that using boiling high pure water to soak the tea leaves forextracting F ion in it,then apply IC to determin the contents of F ion.The reslutsare:the F ion contents in the tea leaves soaking liquid are high,most of them are above1000mg/kg, the individual is less than1000mg/kg.But all of them are out of the range of NY659-2003standard that permitted,which is the contents of F in the tealeaves are less than200mg/kg.