光谱学与光谱分析, 2014, 34 (8): 2254, 网络出版: 2014-08-18  

Box-Behnken设计优化浊点萃取-原子荧光光谱法测定中药材中的汞

Cloud Point Extraction for Determination of Mercury in Chinese Herbal Medicine by Hydride Generation Atomic Fluorescence Spectrometry with Optimization Using Box-Behnken Design
王梅 1,2,*李姗 1,2周建栋 1,2徐英 1,2龙军标 3杨冰仪 1,2
作者单位
1 广东药学院公共卫生学院, 广东 广州510310
2 广东省分子流行病学重点实验室, 广东 广州510310
3 广州市黄埔区疾病预防控制中心, 广东 广州510700
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4 528.74, 实测值与其较接近, 仅有2.1%的差别。汞在1~5 μg·L-1与荧光值有良好的线性关系, 方法检出限为0.012 47 μg·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。
Abstract
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 into 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 methodology 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 dithizone 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·L-1, dithizone concentration of 4.87 mol·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 1~5 μg·L-1. The limit of detection 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 tangerine samples with the recoveries of 95.0%~100.0%. Apparently Box - Behnken design combined with response surface analysis method was considered to be well used for optimization of the cloud point extraction.

王梅, 李姗, 周建栋, 徐英, 龙军标, 杨冰仪. Box-Behnken设计优化浊点萃取-原子荧光光谱法测定中药材中的汞[J]. 光谱学与光谱分析, 2014, 34(8): 2254. WANG Mei, LI Shan, ZHOU Jian-dong, XU Ying, LONG Jun-biao, YANG Bing-yi. Cloud Point Extraction for Determination of Mercury in Chinese Herbal Medicine by Hydride Generation Atomic Fluorescence Spectrometry with Optimization Using Box-Behnken Design[J]. Spectroscopy and Spectral Analysis, 2014, 34(8): 2254.

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