Headspace single-drop microextration for the detection of organotin compounds

The performance of single-drop microextraction (SDME), coupled with gas chromatography/mass spectrometry, was assessed for the determination of tributyltin compounds in water and solid samples. Experimental parameters impacting the performance of SDME, such as microextraction solvent and sampling and stirring time, were investigated. Analytical results obtained by SDME were compared with those generated by conventional solid phase microextraction (SPME) and liquid-liquid extraction (LLE) for the determination of TBT in PACS-2 sediment certified reference material (CRM).     

P-507回流萃取法富集镥的研究——Ⅰ.P-507萃取分离镱镥混合稀土的性能

本文研究了2-乙基己基膦酸单2-乙基己基酯(P-507)在盐酸和硝酸体系中萃取镱镥混合稀土的性能。说明P-507在硝酸体系中的萃取分离系数较其在盐酸体系中高,而在盐酸体系中有更高的反萃效率。与二(2-乙基己基)磷酸(P-204)相比,P-507具有萃取酸度低、易反萃和不易乳化的优点。我们还确定了回流萃取法分离镥镱的基本参数,表明P-507是一种新型的分离重稀土的良好萃取剂。     

醌类化合物的超临界流体萃取研究进展

综述了国内近20年来超临界流体萃取技术应用于醌类化合物分离的研究进展,重点介绍了超临界流体萃取技术在中草药中醌类化合物的分析测定方面的应用,分析了影响醌类成分提取效果的主要因素,优化萃取温度和萃取压力能够改善琨类化合物的分离效果,夹带剂的使用则有效地提高了超临界流体的萃取能力。     

固相萃取-气相色谱-质谱分析肉样中盐酸克伦特罗的残留量

建立了固相萃取 气相色谱 质谱联机分析肉样中盐酸克伦特罗残留量的方法。对盐酸克伦特罗在C1 8和离子交换固相萃取柱上的保留行为进行了研究 ,发现不同浓度盐酸克伦特罗的固相萃取回收率在 75 %～ 95 %之间 ;肉样中的加标回收率在 70 %～ 83 % ;相对标准偏差在 4 .95 %～ 1 3 .4 % ;最低检出限为 1 μg kg。盐酸克伦特罗的硅烷化产物 ,采用选择离子的模式进行检测 ( 86、2 4 3、2 62、2 77) ,衍生物的峰面积与样品浓度在0 .0 0 2 5 2～ 2 .0 2mg L范围内呈良好的线性关系 ,线性回归系数大于 0 .9999。     

毛细管电泳-电感耦合等离子体原子发射光谱法对田七提取液中Fe、Cu和Mg存在状态的研究

提出了以水作溶剂微波萃取提取,并以毛细管电泳电感耦合等离子体原子发射光谱(CE-ICP-AES)法测定田七提取液中Mg、Cu和Fe的形态的分析方法。实验结果表明:Mg仅以游离态存在;而Cu和Fe除了游离态以外,还存在其它三种未知的形态。此外,还测定了田七中20个微量元素的总含量,并得到了上述待测元素在水提取液中的提取率。     

Multifunctional Calix[4]arenes Containing Pendant Amide and Phosphoryl Groups: Their Use as Extracting Agents and Carriers for Alkali Cations

The complexing, extracting and mobile carrier properties of the tetra(phosphine oxide)-calix[4]arene 1 and the hybrid diamide-di(phosphine oxide)-calix[4]arene 2 were studied. Both ligands give 1 : 1 complexes with alkali cations in THF as shown by the picrate method. 1H NMR experiments were run to follow encapsulation of sodium and potassium cations. The corresponding spectra indicate C2-symmetrical structure. The observed extraction orders of the alkali picrates were as follows K+>Rb+>Li+>Cs+>Na+ for 1 and Li+>Na+>K+>Rb++ for 2. Transport kinetics was analysed by means of a model which assumes pure diffusion and which allows the evaluation of mass transfer coefficients in all systems. These coefficients and their influences on the transport rate are discussed in terms of size of the transporting species in the liquid membrane.     

大气飘尘中多环芳烃的超声波萃取- 恒能量同步荧光法测定

采用超声波萃取大气飘尘样品中的多环芳烃,样品不需纯化,直接可用于同步荧光分析,超声波萃取效率高,萃取时间短;采用恒能量同步荧光法对多环芳烃进行定性定量,相关系数r>0.999 1,检出限(3δ)在0.013~4.4 ng之间,回收率为80%~132%。     

Alginate Properties and Heavy Metal Biosorption by Marine Algae

The physical properties of the alginate component in four different brown seaweeds (Sargassumfluitans, Ascophyllum nodosum, Fucus vesiculo-sus, andLaminaria japonica) were characterized using potentiometric titration,¹³C-nuclear magnetic resonance (NMR), chemical analysis, and viscosity measurements. The heavy metal binding capacities of the corresponding seaweeds were directly proportional to their respective total carboxyl group content, and related to the electronegativity of the elements investigated (Ca, Zn, Cd, Cu, and Pb). The uronic acid composition or sequence of the alginate component did not affect the metal uptake properties of the biosorbents studied here. However, the alginate leaching owing to its solubilization by Na ions was observed to decrease with increasing intrinsic viscosity of the extracted alginate, related to its molecular weight, and with increasing apparent acidic dissociation constant, related to the alginate density inside the biomass.     

冠醚B15C5萃取分离锂同位素的阴离子效应

本文研究了B15C5冠醚萃取锂盐时,不同阴离子对体系的同位素分离效应的影响。结果表明,阴离子在冠醚萃取过程中不仅对萃取络合物的稳定性有显著影响,而且阴离子半径及软度越大时,萃取体系的锂同位素分离系数(α_(LI))也越大。