析相微萃取-分光光度法测定茶叶中痕量锌  

Determination of trace zinc in tea samples by microsphere phase separation extraction-spectrophotometry

作　　者：张长花[1] 刘国霞[1] 解胜利[1] 王彩红[1] 

机构地区：[1]滨州学院化学与化工系,山东滨州256603

出　　处：《广东农业科学》2011年第18期130-131,143,共3页Guangdong Agricultural Sciences

基　　金：山东省滨州学院青年项目(BZXYLG200504);山东省滨州学院青年人才创新基金(BZXYQNLG200614)

摘　　要：采用1-(2-吡啶偶氮)-2-萘酚(PAN)为螯合剂,四氯化碳为萃取剂,乙醇为助溶剂,建立了析相微萃取-分光光度法测定茶叶中痕量锌的分析方法,并对影响络合反应和相分离的各种条件进行了优化。优化后的条件为:当水相体积为43.5 mL时,萃取剂四氯化碳为3.0 mL,助溶剂乙醇为3.5 mL,萃取时间为15 min。锌的质量浓度在0.20～8μg/mL范围内与吸光度呈线性关系,相关系数为0.99973,方法的检出限为0.027μg/mL,对锌的质量浓度为1.0μg/mL的样品溶液进行7次平行测定,相对标准偏差为1.73%。该方法用于茶叶中锌的测定,回收率为91.7%～105.6%。A new method for the determination of trace zinc in tea samples by spectrophotometry with microsphere phase separation extraction was developed.With the existence of cosolvent of ethanol and solvent of carbon tetrachloride,1-（2-pyridylazo）-2-naphthol（PAN） with Zn2＋ to form a complex in a homogenous phase.Then the complex was separated out with microsphere from the homogenous phase in the system.Various conditions influencing complexing reaction and phase separation were optimized.When the volume of water 43.5mL,a good extraction efficiency was obtained by using 3.0 mL carbon tetrachloride as extraction solvent,3.5mL ethanol as cosolvent,extracting for 15 min.There was a linear relationship between absorbance and zinc concentration in the range of 0.20～8μg/mL with the correlation coefficient of 0.99973.The detection limit of this method was 0.027 μg/mL.The RSD was 1.73% for seven determination of 1.0 μg/mL zinc.This method had been applied to the determination of zinc in tea samples with the recovery of 91.7%～105.6%.

关 键 词：茶叶 析相微萃取 分光光度法 痕量锌 

分 类 号：O657.32[理学—分析化学] O658.2[理学—化学]