茶叶中稀土总量测定的改进  

A Probe into the Measurement of Lanthanon Contained in Tea

作　　者：董菁 

机构地区：[1]芜湖产品质量监督检验所,安徽芜湖241000

出　　处：《安徽化工》2009年第1期73-75,共3页Anhui Chemical Industry

摘　　要：比较了GB/T5009.94标准中偶氮胂Ⅲ—K显色剂的三波长与二溴羧基偶氮胂显色剂的双峰双波长光度法同时测定茶叶中的稀土总量,稀土标准工作液的测定,前法的相关系数R=0.9948,后法的相关系数R=0.9994。由于茶叶中所含微量元素过多,且二苯胍络合试剂受温度影响变化大,致使三波长法测定茶叶稀土并不适用,而二溴羧基偶氮胂与稀土元素形成稳定的蓝紫色络合物,该法受酸度及共存离子影响小,摩尔吸光系数可达1.54×105～1.741×105,明显优于三波长分光光度法。This paper compares two methods of measuring lanthanon contained in tea, namely, Arsenazo Ⅲ-K and spectrophot ometric determination, with the relative coefficients being R=0.9948 and R=0.9994 repectively. But the former is not applicable because there contain numerous microelements in tea and moreover diphenyl reagent is greatly affected, whereas the latter is obviously superior for it is least affected by acidity and coexi sting ions and Moore absorbency can reach 1.54×10^5～1.741×10^5.

关 键 词：稀土元素 二溴羧基偶氮胂 偶氮胂Ⅲ-K 双峰双波长分光光度法 

分 类 号：O614.33[理学—无机化学]