浊点萃取-火焰原子吸收光谱法测定荔枝和桂圆肉中痕量铜

建立以二乙基二硫代氨基甲酸钠(DDT℃)为配位剂、TritonX-114为表面活性剂的浊点萃取-火焰原子吸收测定荔枝和桂圆肉中痕量铜的方法.研究了溶液pH值、配位剂类型与浓度、表面活性剂类型与浓度、平衡温度和平衡时间等实验条件对浊点萃取效率的影响.在最优的实验条件下,该方法测定铜的检出限为0.8μg/L,相对于传统火焰...     

浊点萃取-胶束增稳室温燐光法测定水样中痕量α-萘乙酸

提出了用非离子表面活性剂Triton X-100作萃取剂的浊点萃取-胶束增稳室温燐光法测定痕量α-萘乙酸的新方法.就溶液pH、试剂浓度、平衡温度和时间等实验条件对浊点萃取的影响及后续使用的胶束增稳室温燐光法的测定条件进行了探讨.在最佳条件下,线性范围为3.0×10-8～2.0×10-6 mol/L;检出限1.3×10-8 mol/L;方法用于强化水样中痕量α-萘乙酸的测定,回收率95%～104%;相对标准偏差2.0%～3.5%.     

浊点萃取-石墨炉原子吸收光谱法对不锈钢餐具溶出铬的形态分析

采用浊点萃取一石墨炉原子吸收光谱法分离和测定不锈钢餐具中的溶出铬.利用六价铬和吡咯烷二 硫代氨基甲酸铵(APDC)间发生选择性络合被萃取到表面活性剂相中,而三价态的铬离子留在水相中,探讨了影响浊点萃取的主要凶素:如pH值、APDC试剂的浓度、Triton X-114的浓度、反应温度和时间.在优化的实验条件下,检出限为0.012μg/L,富集倍数为20倍.     

浊点萃取-火焰原子吸收光谱法测定食品和饮料中的痕量铜

研究了基于非离子表面活性剂TritonX-114和螯合剂二乙基氨基二硫代甲酸钠(DDTC)的浊点萃取-火焰原子吸收光谱法测定痕量铜的分析方法.考察了影响浊点萃取效率的参数,包括pH值、DDTC浓度、TritonX-114用量、平衡温度及时间等.在优化条件下,本法的检出限(3σ)为1.55μg/L,相对标准偏差RSD为3.4%(n=7,c=100μg/L),线性范围为0～250μg/L.将该法应用于茶叶标准样品(GBW07605)、奶粉和矿泉水等样品中痕量铜的测定,其回收率在96.7%～113.5%之间.     

浊点萃取-火焰原子吸收光谱法测定样品中的痕量钴

研究了基于表面活性剂Triton X-114和络合剂吡咯烷二硫代氨基甲酸铵（APDC）浊点萃取钴的样品前处理方法.优化了浊点萃取条件参数,包括pH值、Triton X-114用量、APDC浓度、平衡温度及时间等,建立了浊点萃取-火焰原子吸收光谱法测定痕量钴的方法.该法的检测限（3σ）为2.6μg/L,相对标准偏差RSD为6.2%（n=7,c=200μg/L）.该法成功地应用于海带、维生素B12注射液等样品中钴的测定.     

浊点萃取预富集胶束增稳室温燐光法测定吲哚-3-丁酸

提出了以非离子表面活性剂Triton X-100为萃取剂的浊点萃取预富集吲哚-3-丁酸,进而用胶束增稳室温燐光法对其进行测定的新方法。通过加入氯化钠降低表面活性剂溶液的浊点,使浊点萃取得以在15℃的环境温度下顺利完成。在基于浊点萃取而进行的相分离之后,富表面活性剂相以水适当稀释,然后用胶束增稳室温燐光法测定其中被富集的吲哚-3-丁酸。在最佳条件下,工作曲线的线性范围为1.0×10-8~2.4×10-7mol/L,检出限(信噪比为3)为7.4×10-9mol/L。方法用于自来水、江水、池塘水和土壤等强化样品中吲哚-3-丁酸的测定,回收率95%~105%,相对标准偏差2.5%~4.8%。     

浊点萃取-火焰原子吸收光谱法测定矿渣中痕量金

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。     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的痕量镉

研究了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量镉的新方法,利用表面活性剂Triton X-100和络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)对镉进行浊点萃取。详细探讨了影响浊点萃取及测定灵敏度的因素。优化条件为:0.25 mL 30%NaC l,pH 8.5,0.50 mL、4.0×10-4mol/L PAN,0.2 mL 1.0%TritonX-100。在最佳条件下,镉的富集倍率为50倍,检出限为5.9 ng/L,RSD为2.1%。该方法用于环境样中痕量镉的富集和测定,结果令人满意。     

浊点萃取-超高效液相色谱法检测水中戊菌唑残留量

建立了浊点萃取-超高效液相色谱分析(CPE-UPLC)法测定水中戊菌唑残留量的方法。以非离子表面活性剂PEG-6000为萃取剂,对色谱检测条件和浊点萃取参数进行了探讨和优化。浊点萃取条件为27 g/L PEG-6000,120 g/L Na2SO4,溶液p H为1.5,在45℃水浴中平衡15 min。在选定的色谱条件下,戊菌唑在0.025~5.0μg/m L时其质量浓度与检测信号峰面积呈线性关系,相关系数为0.9997,检出限为1.5μg/L;水样平均添加回收率为91.4%~92.9%,相对标准偏差为1.8%~2.6%。水样中戊菌唑添加质量浓度(0.025~5.0μg/m L)经CPE处理与UPLC检测信号呈线性关系,相关系数为0.9979,检出限为0.2μg/L,方法能满足农药残留检测的要求。     

浊点萃取-石墨炉原子吸收光谱法测定痕量钯

建立了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量金属钯的新方法,利用表面活性剂Triton X-114和络合剂2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)对钯进行浊点萃取。研究了溶液pH、试剂浓度、平衡温度和加热时间等因素对浊点萃取及测定灵敏度的影响。优化条件为:pH 5.50 HAc-NaAc缓冲,0.08 mL 5×10-4 mol/L 5-Br-PADMA,0.70 mL10g/L Triton X-114。在最佳条件下,方法的线性范围为0.1～10 ng/mL,钯的检出限为0.068 ng/mL,富集倍率为45倍。该方法可用于环境样品中痕量钯的富集和测定,结果令人满意。     

混合表面活性剂水溶液的浊点性质

正负离子表面活性剂混合体系在水溶液中很容易形成沉淀，这曾在很大程度上限制了该体系理论性质的研究及其应用。近年来的研究发现，该体系在吸附和胶团形成等方面存在很强的协同效应，对其相关性质的研究越来越多。与单一离子性表面活性剂性质不同，后者的溶解     

Cloud-point extraction of nodularin-R from natural waters

A cloud-point extraction (CPE) technique for the determination of a cyanobacterial hepatotoxin, nodularin-R, in aqueous media using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat-336), was developed. Cloud-point phase separation of Aliquat-336 at ambient temperature was induced by the addition of sodium sulfate. The Aliquat-336/Na₂SO₄ CPE system displayed large preconcentration factor, F_C, for nodularin-R. At the operational CPE conditions, F_C of 709.2 was achieved. Distribution constant, K_D, of the distribution of nodularin-R between the surfactant-rich and aqueous phases of the CPE system was estimated to be (4.94±0.8)×10³. Coupled to liquid chromatography with UV detection, the CPE method offered a detection limit of 330 pg ml⁻¹ (in freshwater)/1.3 ng ml⁻¹ (in seawater) and a repeatability of 6.4% (in freshwater) (n=7, P<0.05) for nodularin-R in a sample of 25 ml. The CPE is a rapid process and no cleanup step is required. Effects of pH, natural abundant anion (chloride) and dissolved organic matters (DOM, humic acid, HA) on the extraction efficiency were evaluated. A double CPE technique was developed to overcome interferences encountered in the analysis of environmental samples. Applicability of the new method to the determination of nodularin-R in real coastal marine water samples has also been demonstrated.     

Studies on transport mechanism of Cr(VI) extraction from an acidic solution using liquid surfactant membranes

A mathematical model for analysing the extraction of Cr(VI) from aqueous acidic solution by emulsion liquid membrane using Aliquat 336 as extractant and NaOH as stripping agent has been presented. The existing models developed so far do not account for the existence of different forms of Cr(VI) ions in the aqueous phase depending on pH conditions. Accordingly, in the present model, reaction equilibrium has been considered instead of distribution coefficient to represent realistically the transport mechanism for this type of system through liquid surfactant membrane. Unlike other models, liquid–liquid equilibrium of sodium hydroxide-chloride of Aliquat 336 has also been considered. The carrier thus exists in the membrane phase in hydroxide and chloride forms and extraction of hexavalent chromium from the external phase proceeds by the two carriers. The validity of the model has been checked from comparison of the simulated curves and experimental data using chemical reaction equilibrium constant and D_eff/R² as fitting parameters.     

Investigation of phase equilibria of levulinic acid distribution between aqueous phase to organic phase by Aliquat 336 in different modifiers

The extraction of levulinic acid by tricaprylmethylammonium chloride (Aliquat 336) dissolved in five alcohols solvents (isoamyl alcohol, hexan-1-ol, octan-1-ol, nonan-1-ol, decan-1-ol) and five esters solvents (dimethyl phthalate, dimethyl adipate, dimethyl succinate, dimethyl glutarate, diethyl carbonate), two ketones (diisobutyl ketone (DIBK), methyl isobutyl ketone (MIBK)) were investigated to understand effect of modifier on levulinic acid extraction. In addition to these Aliquat 336 + modifier system, the experiments were done also with single solvents. All measurements were carried out T = 298.15 K. Organic solutions of Aliquat 336 are being used increasingly to separate organic acids from aqueous mixture solutions by reactive extraction. The extent to which the organic phase may be loaded with levulinic acid is explained as a loading ratio, Z_Z, extraction efficiency E and, distribution coefficients K_D were calculated. The maximum extraction efficiency was obtained value of 72.1 for isoamyl alcohol. The extraction equilibrium constant, K_E, has been calculated for each modifier. Furthermore, Freundlich, Langmuir, and LSER model equations have been obtained for experimental data of alcohols.     

Synchronized extraction and purification of L-lactic acid from fermentation broth by emulsion liquid membrane technique

This study aims to investigate the recovery of L-lactic acid from fermentation broth by an emulsion liquid membrane (ELM), made up of sunflower oil as the diluent, Sorbitan monooleate (Span 80) as the surfactant, Aliquat 336 as the carrier, and sodium hydroxide (NaOH) solution as the internal aqueous phase. Particularly, the ELM process was properly set up, through the identification of the optimal ELM operating parameters on the final extraction efficiency of L-lactic acid, including Span 80 concentration, NaOH concentration, Aliquat 336 concentration, stirring speed, phase ratio, and treatment ratio. The obtained results showed that the extraction efficiency of L-lactic acid reached up to 99% under the following optimal conditions: 10 minutes after contact time, 4% w/w Span 80, 3% w/w Aliquat 336, 0.1?N solution of NaOH, stirring speed of 300?rpm, phase ratio 1, and treatment ratio 0.25. A stable system without considerable emulsion swelling and breakage was monitored using a dynamic light scattering (DLS) apparatus for the selected optimal ELM operating parameters.     

Separation of niobium and tantalum through solvent extraction and reversed phase extraction chromatography using Aliquat 336 as an anion exchanger

Niobium and tantalum which have close chemical similarities have been separated through two different methods, viz. solvent extraction and reversed phase extraction chromatography (RPEC) in tracer scale using Aliquat 336 as a liquid anion exchanger. Quantitative extraction of tantalum in the organic phase from 0.05M HF solution by 5·10^–4M Aliquat 336 solution was achieved leaving niobium in the aqueous phase. In RPEC, hydrophobized kieselguhr impregnated with Aliquat 336 was used as the stationary phase in the column from which niobium was first eluted with 0.1M HF and then tantalum with 10M HNO₃ solution. The purity of the separated isotopes in both the procedures were verified by means of gamma-ray spectrometry.     

Extraction and preconcentration of salbutamol and terbutaline from aqueous samples using hollow fiber supported liquid membrane containing anionic carrier

This paper presents a new three-phase liquid-phase microextraction (LPME) strategy for extraction and preconcentration of salbutamol (SB) and terbutaline (TB) from aqueous samples, including urine. The drugs were extracted from 11 ml of aqueous sample (source phase; SP) into an organic phase with microliter volume located inside the pores of a polypropylene hollow fiber, and then back-extracted into 24 microl of a second aqueous solution as the receiving phase (RP), located in the lumen of the hollow fiber. In preliminary experiments, we tried to transport the drugs using a pH gradient between the two sides of the hollow fiber. Due to the existence of both amine and phenolic groups on the drugs, very little transport occurred and enrichment factors (EF) less than one were obtained. Further experiments were done in the presence of bis(2-ethylhexyl) monohydrogenphosphoric acid (D2EHPA) or methyltrioctylammonium chloride (Aliquat 336) in the organic phase, to extract drugs from acidic and basic matrices, respectively. Results showed that transport of drugs from alkaline solution into 1M of sodium bromide occurred when the membrane was impregnated with dihexyl ether containing 20% Aliquat 336. To optimize the EF, the effects of different parameters such as the nature of organic solvent used to impregnate the membrane, compositions and volumes of SP and RP, type and concentration of carrier, extraction time and stirring rate were investigated. Optimal results were obtained in the presence of 0.005 M of NaOH (pH 11.70) in the SP, 1M of NaBr in the RP, 20% of Aliquat 336 in dihexyl ether as membrane impregnation solvent, stirring rate of 500 rpm and extraction time of 60 min. Under these conditions, enrichment factors of 52.9 and 213.1, dynamic linear ranges of 20-5000 and 10-5000, and limits of detection of 2.5 and 0.5 ng/ml were obtained for salbutamol and terbutaline, respectively. Also determination of drugs in environmental water and urine samples in the range of nanograms per millilitre with RSDs<10% was possible using HPLC-photodiode array detection or HPLC-MS.     

Extraction and separation of Zr,Nb and Hf by Aliquat 336 and its mixtures with TOPO from acidic thiocyanate media

Presence of thiocyanate ions results in appreciable extraction of Zr(IV) by Aliquat 336 from low aqueous HCl acidities, i.e., 0.1 to 4.5M. The variation of concentrations of HCl, thiocyanate and Aliquat 336 greatly influences the extent of extraction. Mixtures of Aliquat 336 and TOPO result in synergistic extraction of Zr and Hf from acidic thiocyanate media, the extracted species being the disolvate with TOPO. By controlled adjustment of HCl, SCN^– and Aliquat 336 concentrations, separation of Zr, Nb and Hf is possible. A maximum separation factor (D_Nb/D_Zr) of 3675 has been achieved under certain conditions.     

Liquid-liquid extraction of 233Pa(V) with Aliquat 336</p> </p>

Summary The extraction of protactinium with Aliquat 336 (methyl-tri-caprylyl ammonium chloride) in toluene, cyclohexane and chloroform from HCl, HNO₃, H₂SO₄, HClO₄, HF and mixed HCl-HF media was investigated by radioactive tracer technique. Distribution ratios of protactinium between the aqueous solution and the organic phase were determined as a function of shaking time, concentrations of acid in aqueous solution phase, extractant concentration and type of diluents in the organic phase. Aliquat 336 can almost quantitatively extract protactinium from strong HCl solution. At the same time, small amounts of HF in HCl solutions have a strong effect on Pa distribution.</p> </p>     

Effect of the nature of diluent on the extraction of beryllium by Aliquat 336 thiocyanate

The extraction behaviour of beryllium from HCl-KCNS by Aliquat 336, a quaternary ammonium halide, in various diluents is described. The dependence of extraction on thiocyanate concentration, pH of aqueous phase, metal and extractant concentrations, has been investigated. Extraction mechanism is suggested on the basis of results obtained.