痕量铊的液膜分离富集与测定

以正十六胺-L113B-煤油为膜相，内相为0．040mol／L的NaOH溶液；外相为0．040mol／L的KCl和0．060mol／L的HCl溶液对痕量铊进行分离富集。实验结果表明，Tl(Ⅲ)的迁移率达99．5％以上。在合适的条件下，可与其它离子分离。此法可用于黄铁矿样品中微量铊的分离富集，以火焰原子吸收光谱法测定，回收率在99％以上。本文还对Tl(Ⅲ)的液膜富集机理进行了讨论。     

水体中铊的富集分离方法的研究进展

综述了近20年来。水体中铊的富集分离方法,如物理方法、化学方法、生物方法和电化学方法的研究现状,讨论了不同方法的优缺点,展望了水体中铊富集分离方法的发展方向(引用文献42篇)。     

矿石中微量铊的吸附催化极谱测定

铊在矿石中的含量一般都很低。极谱法测定铊,常采用先经有机溶剂反复萃取,然后在氟化钾的碱性底液中测定。碘化钾可使镉、铅产生吸附催化波。本文提出在20％氟化钾,0.15％碘化钾的碱性底液中,铊可产生吸附催化波,可使灵敏度提高10倍。采用硫酸、氟化钾分离铅、铁等元素;利用二氧化锰共沉淀铊,使铜、锌、镉等元素大部分被分离出去。这样分离和富集铊不但避免了有机溶剂反复萃取,而且可测出样品中0.0000x％的铊。本法适用于硫化矿中微量铊的测定。     

泡沫塑料吸附分离石墨炉原子吸收测定地质样品中微量铊

地球化学样、单矿物及一些岩石样品常需分析微量铊,其含量有时小于10~(-5) ％。测定这样微量的铊尚无很好的方法。石墨炉原子吸收法灵敏度高,适于微量铊的测定,但已有方法都使用有机溶剂萃取分离,效果差。用泡沫塑料吸附方法作为一种分离富集手段,能解脱制备为水性溶液,很适合于石墨炉原子吸收分析,目前,已应用于测金、砷及稀土等。本文就聚氨醋泡沫塑料富集分离微量铊进行了研究,在含适量卤素离子(Br~-、Cl~-或F~-)的稀     

邻羟基苯基重氮氨基偶氮苯分光光度法测定地质样品中的痕量铊

１引言 铊是稀散元素，在制造电子元器件、化学、玻璃及半导体工业等领域有重要用途。铊也是剧毒元素，其毒性为氧化砷的３倍多。随着铊的使用日益增多，它的环境效应引起了人们的关注，因此铊的分析工作越来越重要。近年来，水相胶束增溶分光光度法测定铊的研究日趋增加。邻羟基苯基重氮氨基偶氯苯（Ｏ－ＨＤＡＡ）曾用于锌、银、镉、镍、钴等的光度分析。本文详细研究了在 Ｔｒｉｔｏｎ Ｘ－１００存在下，Ｏ－ＨＤＡＡ与铊的高灵敏显色反应。聚胺酯泡沫塑料对铊有很好的吸附性能，本文用于分离富集铊。建立了一个在水相体系中快速、准确…     

聚酰胺富集吸光光度法测定金

ＰＶＣ－聚己内酰胺作为金的富集利，从稀盐酸或王水介中富集微量金，具有吸附速度快，容易洗脱，吸收容量大等优点，在选择的色层条件下，除贵金属和铊外，普通离子不被吸附，可广泛用于分离富集各类矿物中微量金。     

氧化石墨烯/硫杂杯芳烃复合材料富集分离-石墨炉原子吸收法测定痕量铊

自制了一种新型氧化石墨烯/硫杂杯芳烃复合材料,用扫描电镜、红外光谱、元素分析、热分析对合成产品进行表征,用于痕量铊的富集,提出了氧化石墨烯/硫杂杯芳烃复合材料分离预富集,石墨炉原子吸收光谱法测定痕量铊的一种新方法,探讨了溶液pH值、温度、洗脱条件及干扰离子对痕量铊分离富集的影响,结果发现该材料对Tl3+具有较大吸附量。在pH 8.0,温度为(23±1)℃条件下,铊可被该材料定量吸附,其吸附容量为73.1 mg/g。吸附的铊可被5.0 mL酸性硫脲(0.5 mol/L HCl+1.0 mol/L硫脲)完全洗脱,方法的线性范围为0.012~15μg/L,检出限(3σ)为0.008μg/L,对0.50μg/L Tl3+工作液测定的RSD(n=7)为2.3%,加标回收率为93.6%~104.1%。此法用于生物样品和环境水样中痕量铊的测定,结果满意。     

泡沫塑料富集–石墨炉原子吸收光谱法测定贝类水产品中痕量铊

采取微波消解的前处理手段消解样品,经泡沫塑料分离富集后,用石墨炉原子吸收光谱法测定贝类水产品中痕量铊。以1.5 mL Fe3+,2 mL H2O2和5%王水介质作为吸附体系将样品中铊分离富集,再以硝酸钯、抗坏血酸作为基体改进剂进行测定。铊的质量浓度在0～50μg/L范围内线性良好,相关系数为0.999 7,方法的检出限可达0.07μg/g。测定结果的相对别准偏差为1.53%～4.01%(n=7),加标回收率为87.1%～98.3%。泡沫塑料富集–石墨炉子吸收光谱法测定贝类水产品中痕量铊是一种准确、安全、便捷的检测方法。     

电感耦合等离子体质谱法测定多金属矿中铟和铊

正稀散元素铟和铊在自然界中含量并不稀少,但较为分散,常伴生在磁铁矿、硫化矿、多金属矿、煤、铝土等矿床中,很少富集形成单矿物[1]。测定稀散元素铟和铊的含量,对开发利用矿产资源及综合评价具有重要的作用[2-4]。测定铟和铊的传统方法有极谱法、分光光度法、氢化物原子荧光光谱法、原子吸收光谱法等[5-6]。由于铟和铊的含量较低,这些方法通常需要将样品分离、富集、萃取等过程繁琐,分析效率偏低。近年来     

铊的萃取色层分离及其在测定矿石中微量铊的应用

两年前,我们在研究“铟的萃取色层分离及其在测定矿石中微量铟的应用试验中发现,在氢溴酸-磷酸三丁酯(TBP)体系中,铊、金和铟一起被萃取在固定相上。用水洗脱铟后,铊和金仍留在固定相上。在此试验结果的启发下,我们继续进行了铊的萃取色层分离及其在测定矿石中微量铊的应用。本文仍用TBP-0.8MHBr体系萃取色层富集铊,再用抗坏血酸-柠檬酸钠-柠檬酸溶液洗脱铊,最后以结晶紫萃取比色测定铊。试验表明,本法选择性好,灵敏度高,能应用于测定复杂矿石中0.0002％以上的铊。试验中所用的固定相和色层柱都按前文的操作手续制备。铊的标准是称取光谱纯三氧化二铊用盐酸溶解配制而成。     

环境领域铊元素的分析技术研究进展EI北大核心CSCD

铊是一种剧毒的蓄积性重金属元素。伴随着含铊矿物资源的开发利用,铊向环境中的迁移已不容忽视,环境铊污染事件时有发生。铊的分析技术对铊污染的防治具有重要意义。环境领域铊的分析技术近年来也有了新的发展。重点对环境水体、土壤、大气中铊元素分析技术的近期发展进行了综述。在电感耦合等离子体-质谱(ICP-MS)、石墨炉原子吸收光谱(GF-AAS)法为主流分析手段的同时,随着铊新型富集技术的应用以及仪器性能的提升,环境铊分析技术呈现出高灵敏、高稳定性的趋势。针对环境领域铊元素分析技术的发展,提出环境样品铊的化学及赋存形态分析、铊的在线监测、与铊高效富集技术的联用以及环境固体废物中铊的分析是其重要的发展方向。     

Anodic stripping voltammetric determination of thallium as [TlBr4]-rhodamine B complex

The anodic stripping voltammetric behaviour of the [TlBr₄]-rhodamine B complex is described and compared with that of thallium(I) and thallium(III) ions. The electrolyte composition, the best potential for the deposition of thallium from the complex in the selected electrolyte, the duration of the electrolysis, and the possibility of reduction of thallium in the [TlBr₄]-rhodamine B complex before the electrolysis with ascorbic acid were investigated. The results showed good reproducibility of the measurements of thallium as [TlBr₄]-rhodamine B complex and are similar to those obtained for thallium as Tl(I) and Tl(III) ions. As the [TlBr₄]-rhodamine B complex is strongly adsorbed on polyethylene, a previous preconcentration step on a column, packed with polyethylene powder, allowed the voltammetric determination of thallium as [TlBr₄]-rhodamine B complex in samples of KCl and NaCl as solid salts after the separation of the matrix. With this procedure it was possible to reach enrichment factors of 25 with recoveries from 96.7 to 107.9% for thallium concentrations from 5 to 40 μg L^–1 and RSD between 4.2 and 9.2%. The procedure was used to determine thallium traces in KCl and in sea salt. The results of these determinations were compared with the results obtained by graphite furnace atomic absorption spectrometry.     

Selective solid-phase extraction of trace thallium with nano-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> from environmental samples

A novel sorbent, nano-Al₂O₃ was employed for the separation and preconcentration of thallium from aqueous solution in batch equilibrium experiments. It was found that the adsorption percentage of thallium ions was close to 100% at pH 4.5, and the desorption by 1.0 mL of 0.25 M HCl reached 99%. The adsorption equilibrium was well described by the Langmuir isotherm model with maximum adsorption capacity of 5.78 mg/g (20 ± 0.1°C). The enrichment factor values of Tl(III) was 25 for 25 mL sample. Detection limit of thallium (3σ, n = 11) equal to 0.8 μg/mL and relative standard deviation (2.4%) were obtained. The method has been successfully applied to the determination of trace thallium in some environmental samples and the certified reference material polymetallic nodule (GBW07296) with satisfactory results.     

Anodic stripping voltammetric determination of thallium as [TlBr4]-rhodamine B complex

The anodic stripping voltammetric behaviour of the [TlBr₄]-rhodamine B complex is described and compared with that of thallium(I) and thallium(III) ions. The electrolyte composition, the best potential for the deposition of thallium from the complex in the selected electrolyte, the duration of the electrolysis, and the possibility of reduction of thallium in the [TlBr₄]-rhodamine B complex before the electrolysis with ascorbic acid were investigated. The results showed good reproducibility of the measurements of thallium as [TlBr₄]-rhodamine B complex and are similar to those obtained for thallium as Tl(I) and Tl(III) ions. As the [TlBr₄]-rhodamine B complex is strongly adsorbed on polyethylene, a previous preconcentration step on a column, packed with polyethylene powder, allowed the voltammetric determination of thallium as [TlBr₄]-rhodamine B complex in samples of KCl and NaCl as solid salts after the separation of the matrix. With this procedure it was possible to reach enrichment factors of 25 with recoveries from 96.7 to 107.9% for thallium concentrations from 5 to 40 μg L^–1 and RSD between 4.2 and 9.2%. The procedure was used to determine thallium traces in KCl and in sea salt. The results of these determinations were compared with the results obtained by graphite furnace atomic absorption spectrometry. Received: 5 February 1998 / Revised: 19 May 1998 / Accepted: 29 May 1998     

Speciation analysis of thallium using electrothermal AAS following on-line pre-concentration in a microcolumn filled with multiwalled carbon nanotubes

The enrichment ability of carbon nanotubes (CNTs) was investigated and a new method established for the determination of trace thallium species in environmental samples using electrothermal atomization-atomic absorption spectrometry (ETAAS). The CNTs were employed as sorbent substrate in a continuous flow system coupled to ETAAS. Parameters influencing the recoveries of thallium were optimized. Under optimal conditions, the detection limit and precision of the method were 0.009 µg L^?1 and 3.9%, respectively. The method was applied to the determination of thallium in real environmental samples and the recoveries were in the range from 96 to 100%. This system was able to separate thallium (I) from the matrix, which allowed its selective determination. The total thallium content was then determined by reducing Tl(III) with hydroxylamine. All these experimental results indicated that this new procedure can be applied to the determination of trace thallium in drinking water samples.     

Extraction separation of thallium (III) from thallium (I) with n-octylaniline

A novel method is developed for the extraction separation of thallium(III) from salicylate medium with n-octylaniline dissolved in toluene as an extractant. The optimum conditions have been determined by making a critical study of weak acid concentration, extractant concentration, period of equilibration and effect of solvent on the equilibria. The thallium (III) from the pregnant organic phase is stripped with acetate buffer solution (pH 4.7) and determined complexometrically with EDTA. The method affords the sequential separation of thallium(III) from thallium(I) and also commonly associated metal ions such as Al(III), Ga(III), In(III), Fe(III), Bi(III), Sb(III) and Pb(II). It is used for analysis of synthetic mixtures of associated metal ions and alloys. The method is highly selective, simple and reproducible. The reaction takes place at room temperature and requires 15-20 min for extraction and determination of thallium(III).     

Recent advances of rhenium separation and enrichment in China: Industrial processes and laboratory trials

The recent progresses in the separation and enrichment of rhenium were reviewed in this paper, especially, the advances in China.     

Coulometric titrations with an ion exchange separation step

Summary The coupling is described of coulometric separation methods with an ion exchange separation step. Various methods of enrichment and separation are described using the analysis of nitrogen compounds, such as ammonia, urea and nitrite, as examples. A microcomputer controls the separation step and regulates the coulometric determination. Quantitative separations are achieved in all cases, so that the advantage of coulometric titration, as a precise absolute determination method, is retained.     

Separation of thallium-201 from Tl,Pb and Bi cyclotron target materials

Radiochemical methods of thallium-201 separation from proton-irradiated thallium, lead and bismuth targets have been developed. The procedures are based on the processes of coprecipitation, ion-exchange chromatography and high temperature gas chemistry. The purity of thallium samples complies with requirements of nuclear medicine for thallium-201 product.     

Determination of thallium at subtrace level in rocks and minerals by coupling differential pulse anodic-stripping voltammetry with suitable enrichment methods

Ten international reference samples have been analysed for thallium content by differential pulse anodic-stripping voltammetry. Two separation techniques, solvent extraction and ion-exchange, were employed to preconcentrate the thallium: the results were critically compared to establish which was the better separation technique. The values found were quite satisfactory and confirmed the wide scope for application (not yet fully investigated) of voltammetry in geochemical studies.