摘要
建立了浊点萃取分离原子荧光光谱法测定中药材中痕量汞的方法。Hg2＋可与双硫腙生成疏水性螯合物，水浴加热15 min，鳌合物被萃取到Triton X-114表面活性剂相，经离心与水相分开。在单因素基础上，筛选出对萃取效率有较为显著影响的四因素-溶液pH、Triton X-114浓度、双硫腙浓度和平衡温度，并首次采用Box-Behnken设计和响应面法优化实验参数。结果表明，响应值与因素之间可采用二项式拟合，四个因素的一次项和二次项，以及pH 和Trion X-114、双硫腙交互项对萃取率影响显著，p＜0．05；浊点萃取的最佳条件为：pH 值为5．1，Trion X-114浓度1．16 g·L-1，双硫腙浓度为4．87 mol·L-1，平衡温度为35．6℃，理论荧光值4528．74，实测值与其较接近，仅有2．1％的差别。汞在1～5μg＆#183;L-1与荧光值有良好的线性关系，方法检出限为0．01247μg＆#183;L-1，RSD为1．30％。该方法成功用于巴戟天、穿心莲和陈皮中汞含量的测定，加标回收率为95．0％～100．0％。Box-Behnken设计结合响应面分析法可以很好的用于浊点萃取条件的优化。
Cloud point extraction （CPE）is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by hydride generation-atomic fluorescence spectrometry （HG-AFS）.Hg2＋ was reacted with dithizone to form hydrophobic chelate under the condition of pH.Using Triton X-114,as surfactant,chelate was quantitatively extracted in-to small volume of the surfactant-rich phase by heating the solution in a water bath for 15 min and centrifuging.Four variables including pH,dithizone concentration,Triton X-114 concentration and equilibrium temperature （T）showed the significant effect on extraction efficiency of total Hg evaluated by single-factor experiment,and Box-Behnken design and response surface method-ology were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum extraction efficiency.The results showed that the binomial was used to fit the response to experimental levels of each variable.ALL linear,quadratic terms of four variables,and interactions between pH and Trion X-114,pH and di-thizone affected the response value（extraction efficiency）significantly at 5% level.The optimum extraction conditions were as follows：pH 5. 1,Triton X-114 concentration of 1. 16 g＆#183;L-1 ,dithizone concentration of 4. 87 mol＆#183;L-1 ,and T 58. 2 ℃,the predicted value of fluorescence was 4 528. 74 under the optimum conditions,and the experimental value had only 2. 1%difference with it.Under the conditions,fluorescence was linear to mercury concentration in the range of 1~5μg·L-1 .The limit of de-tection obtained was 0. 012 47 μg·L-1 with the relative standard deviations （R.S.D.）for six replicate determinations of 1. 30%.The proposed method was successfully applied to determination of Hg in morindae Radix,Andrographitis and dried tan-gerine samples with the recoveries of 95. 0%~100. 0%.Apparently Box- Behnken design combined with response surface anal-ysis method was considered to be well used for optimization of the cloud point extraction.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2014年第8期2254-2258,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(81202251)
广东省医学科研基金项目(A2012555)
广东省中医药管理局基金项目(20122111)
国家级大学生创新创业训练计划项目(201310573003)资助
