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1.
乳状液膜分离技术已经在许多领域中应用,在液膜中加入流动载体,可促进物质的迁移.本文从萃取剂中筛选出来双硫腙,可作为铅、铜离子迁移的优良流动载体.用双硫腙-Span 80-甲苯的乳状液膜体系,在20~30min试验中,铅、铜的迁移率均接近100%,而在同样条件下,锌不迁移,因此,用该乳状液体系可分离铅、铜和锌.  相似文献   
2.
双硫腙-活性炭柱富集分离水中痕量铅的条件研究   总被引:1,自引:0,他引:1  
本文研究了用活性炭加双硫腙柱富集、分离水中痕量铅的适宜条件。用火焰原子吸收法分析了不同分离条件下铅的回收率。并讨论了几种干扰离子的影响情况。  相似文献   
3.
A novel method has been developed for the sensitive determination of mercury in aqueous media by room temperature phosphorescence (RTP). The measurement principle is based on the energy transfer (ET) from a phosphor molecule (acting as a donor) to a Hg-sensitive dye (acceptor). To our acknowledgment this is the first RTP method for mercury measurement developed so far. α-Bromonaphthalene (BrN) was selected as the phosphorescent donor molecule (BrN can produce significant RTP emission in aqueous media in a β-cyclodextrin rigid microenvironment without deoxygenation).The absorption spectrum of the complex formed between mercury and the dithizone dye possesses a desirable spectral overlap with the RTP emission spectrum of the donor (BrN), giving rise to a nonradiative ET from the phosphor molecules to the mercury complex. An increase in the concentration of Hg(II) causes an increase on the concentration of the dithizone complex (acceptor) with the subsequent increase of the absorbance and, therefore, resulting in a decrease of the RTP emission. Both, RTP intensities and triplet lifetimes of the BrN decreased with increases on the Hg(II) concentration.Possible interferences present in natural waters, including different cations and anions, which could affect the analytical response, were evaluated and the analytical performance characteristics investigated. The use of phosphorescence measurements (low background noise signals) resulted in an improvement on the sensitivity of the Hg(II) detection higher than five times as compared to the molecular absorption spectrophotometric method for Hg(II) detection based on dithizone as Hg-indicator. A detection limit (D.L.) of 14 ng ml−1 of Hg(II) was obtained by RTP with a precision of ±4.8% for five replicates of 300 ng ml−1 of Hg(II). The usefulness of the method was successfully evaluated by the determination of Hg(II) in spiked natural water samples.  相似文献   
4.
The equilibrium constants and molar absorptivities for the fast formation of a 1:3 complex between cadmium(II) (Cd(II)) and dithizonate anion, in the presence of cationic and non-ionic surfactants, allowed a simple and fast spectrophotometric determination of total cadmium. Indeed, the molar absorptivities of the Cd(II)-dithizone (Dz) complex formed in the presence of the neutral Triton X-100 and cationic cetyltrimethylammonium bromide (CTAB) surfactants are almost twice the value observed in the standard method and the maxima of absorption are shifted by about 40 nm when compared with the standard method. Clearly, the use of neutral and cationic surfactants promotes a higher value of the molar absorptivities of the complex, resulting in an increase in the sensitivity of the method. Application of the method to the desorption of Cd(II) ions from clays is illustrated.  相似文献   
5.
Amberchrom CG-300m, a styrene acrylic ester polymer resin, was studied for the first time as sorbent for metal ion sorption in a solid-phase extraction system. The polymer sorbent was modified via impregnation with dithizone to improve its efficiency. Efficiency of the modified sorbent improved by more than 47%. The loading capacity of the resin is 3.2 mg dithizone per gram of sorbent. The mechanisms of Cd(II) sorption from aqueous solutions are presented. Capacity of the modified resin for Cd(II) was investigated in batch experiments as a function of pH, initial metal ion concentration, temperature and time. Maximum capacity of 0.551 mg Cd(II) per gram of sorbent was achieved. The dimensionless separation factor, 0 < RL < 1, associated with the Langmuir isotherm (at T = 294 K) signifies sorption of Cd(II) was favorable, as do negative values of free energy of sorption (ΔG) at temperatures exceeding 293 K. Sorption was endothermic (ΔH > 0) while ΔS > 0 reflects the affinity of the sorbent towards Cd(II). The pseudo-second order model proved to be the best fit model for Cd(II) sorption kinetics data. Particle-diffusion models suggest sorption follows film as well as pore diffusion mechanisms.  相似文献   
6.
使用 PT- C18色谱预处理柱 ,以双硫腙为螯合剂 ,甲醇为洗脱剂 ,采用流动注射在线分离富集与原子吸收联用技术 ,对银的测定进行了研究。 1 min富集 ( 4 .2 m L)的富集倍率 2 4 ,检出限为 0 .6 2μg/ L,相对标准偏差为 1 .8% ( n=7)。  相似文献   
7.
双硫腙-棉花柱富集分离水中痕量铅的条件研究   总被引:3,自引:1,他引:2  
本文研究了用双硫腙浸泡过的棉花来富集、分离水中痕量铅的适宜条件,讨论了几种金属离子对铅测试的影响,用火焰原子吸收法分析了不同分离条件铅的回收率。  相似文献   
8.
《Analytical letters》2012,45(9):1442-1453
A novel method to preconcentrate gold was developed employing a synergistic enhancement of a room temperature ionic liquid combined with hollow fiber liquid phase micro-extraction with flame atomic absorption spectrometry detection. The method is based on the complexation of gold with dithizone. The formed hydrophobic complex was subsequently extracted into the lumen of a hollow fiber. The organic phase was siphoned into FAAS for the determination. A room temperature ionic liquid and dithizone were used the enhancement reagent and chelating reagent, respectively. The addition of a room temperature ionic liquid led to a five-fold improvement in the extraction of gold. The 1-octanol was immobilized in the pores of the polypropylene hollow fiber as the liquid membrane and was also used as the acceptor solution. Some parameters that influenced extraction and determination were evaluated in detail, such as concentrations of the ionic liquid and dithizone, pH of samples, stirring rates, extraction time, and interferences. Under optimized conditions, a detection limit of 0.9 ng mL?1 and an enrichment factor of 130 were achieved. The relative standard deviation (RSD) was 3.7% for Au (40 ng mL?1, n = 5). The proposed method was successfully applied to the determination of gold in certified reference environmental samples and ore samples with satisfactory results.  相似文献   
9.
A non-aqueous electrochemical study of dithizone, H2Dz, 1, is compared with the chemical oxidation and reduction profile of this versatile ligand. Chemical oxidation of 1 by I2 initially leads to an isolatable disulfide-bridged species, (HDz)2, 22, but ultimately monomeric dehydrodithizone, Dz, 3, is formed. Electrochemically, in CH2Cl2/0.1 mol dm−3 [N(nBu)4][B(C6F5)4], two oxidation processes are observed for 1. Evidence of the electrochemical formation of the dimer 22 was found, but on a CV timescale the fully oxidized species, 22oxidized, did not convert to the chemically stable species 3. Regeneration of 1 during an irreversible electrochemical reduction of the electrochemically generated fully oxidized species, 22oxidized, was detected. Two further one-electron electrochemical irreversible reduction steps were also identified to ultimately generate H3Dz, 8, one of the synthetic precursors to 1. In contrast, resolution and identification of the electron transfer steps of 1 in both dimethylsulfoxide, DMSO, or in CH2Cl2/0.1 mol dm−3 [N(nBu)4][PF6] were hampered by solvation and ion paring of [PF6] especially with the oxidized species of 1. A metathesis of water-soluble potassium dithizonate, KHDz, 4b, led to lipophilic [N(nBu)4][HDz], 4c.  相似文献   
10.
研究了以双硫腙为络合剂,以非离子型表面活性剂Triton X-100为萃取剂的浊点萃取-火焰原子吸收光谱法(CPE-FAAS)测定痕量金(Ⅲ)的新方法。详细考察了溶液的pH值、络合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。该方法的线性范围为0.05~0.8μg/mL,检出限为7.9 ng/mL,相对标准偏差为4.12%(n=11),回收率在98.0%~102.0%之间,用于矿渣中金的测定,结果满意。  相似文献   
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