Column chromatographic separation of gallium, indium and thallium

Distribution ratios are given for the extraction of gallium-(III), indium(III) and thallium(III) from aqueous solutions of hydrobromic acid into di-isopropy ether and isobutyl methyl ketone. Based on the results obtained, a scheme is presented for the quantitative separation of these elements from each other by liquid-liquid partition chromatography. The effect of a number of other metal ions upon the separation is also studied. The separation method has been applied to the analysis of a series of lead-indium alloys.     

Simultaneous recovery of cadmium and lead from aqueous effluents by a semi-continuous laboratory-scale polymer enhanced ultrafiltration process

Performance of a semi-continuous polymer enhanced ultrafiltration (PEUF) process has been investigated for the simultaneous recovery of cadmium and lead from binary mixtures. This method uses poly(acrylic acid) as water-soluble polymer to bind these metals. Experiments have taken place in a laboratory-scale system. Loading ratio (mg total metal ions/g polymer) and pH values for separation of cadmium and lead have been studied by means of preliminary experiments, analyzing their influence on permeate flux, metal rejection coefficients and separation factor.The proposed process includes three different stages: total retention of metal ions, selective separation and polymer regeneration. Operating pH values for total retention of metal ions and polymer regeneration processes are 5 and 2, respectively. Selective separation has been investigated working at an intermediate pH value. In this way, if a stream containing 12.5 ppm of each metal ion (1:1 in weight) is treated in the first stage, two different streams enriched in each metal ion are obtained in the second stage. Permeate stream is enriched in cadmium with a proportion near 5:1 in weight, and retentate is enriched in lead with a similar proportion.Finally, the three stages have been modelled successfully with a mathematical model based on conservation equations and chemical reactions taking place in solution.     

Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Carbohydrates are an extremely complex group of isomeric molecules that have been difficult to analyze in the gas phase by mass spectrometry because (1) precursor ions and product ions to successive stages of MS(n) are frequently mixtures of isomers, and (2) detailed information about the anomeric configuration and location of specific stereochemical variants of monosaccharides within larger molecules has not been possible to obtain in a general way. Herein, it is demonstrated that gas-phase analyses by direct combination of electrospray ionization, ambient pressure ion mobility spectrometry, and time-of-flight mass spectrometry (ESI-APIMS-TOFMS) provides sufficient resolution to separate different anomeric methyl glycosides and to separate different stereoisomeric methyl glycosides having the same anomeric configuration. Reducing sugars were typically resolved into more than one peak, which might represent separation of cyclic species having different anomeric configurations and/or ring forms. The extent of separation, both with methyl glycosides and reducing sugars, was significantly affected by the nature of the drift gas and by the nature of an adducting metal ion or ion complex. The study demonstrated that ESI-APIMS-TOFMS is a rapid and effective analytical technique for the separation of isomeric methyl glycosides and simple sugars, and can be used to differentiate glycosides having different anomeric configurations.     

Extraction of metal ions by N-phenyl-, N-methyl-, and N-unsubstituted hydroxamic acid resins

Procedures are described for preparing macroreticular chelating resins with hydroxamic acid or N-methylhydroxamic acid functional groups. The chelating properties of the resins are compared with each other and with an N-phenylhydroxamic acid resin reported earlier. The extraction of 19 metal ions was studied as a function of pH for the N-methylhydroxamic acid resin. Several analytical applications of this resin have been demonstrated including the purification of chemical reagents, concentration of trace metal ions, and chromatographic separation of metal-ion mixtures.     

Capillary electrophoresis as a nanoreactor of separation capability: on-capillary reaction catalyzed by transition metal ions

The catalytic oxidation of 1,2-dihydroxy-benzene-3,6-disulfonate (tiron) by metal ions has been studied for detection of the metal ions in capillary electrophoresis (CE). Although Co(2+) shows the strongest catalytic capability, some other metal ions also catalyze this reaction. If metal ions encounter a H(2)O(2 )zone after electrophoretic separation in the running buffer containing tiron, tiron is catalytically oxidized while the metal ion passes through the H(2)O(2) zone. Anionic tiron radicals produced by the reaction are finally measured by the detector; in this scheme, the capillary acts as a nano- or microreactor as well as a microseparator. The effective capillary length can be controlled by changing the interval between metal ion and H(2)O(2) injections. This scheme has been successfully applied to the detection of Co(2+), Cu(2+), Mn(2+), and VO(2+). The detectability is discussed from several viewpoints, such as the intrinsic catalyst ability of metal ions, the kinetics of the catalytic reaction, and reaction times determined by the mobility of the zone of the metal ion. Some strange behaviors, which cannot be predicted by batch experiments, are also reported.     

Determination of trace amounts of metals in saline water by energy dispersive XRF using the NaDDTC preconcentration

A simple method for the determination of trace concentrations of metals in saline water is described. The analytical procedure involves the separation of metal ions of Cu, Zn, Hg and Fe by precipitation with diethyldithiocarbamate (DDTC). The radioisotope X-ray fluorescence method using Si(Li) detector has been applied for the determination of metal ions closed in the DDTC deposition.     

Microfluidics in Inorganic Chemistry

The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost‐saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.     

Preparation and analytical properties of a chelating resin containing bicine groups

A polystyrene divinyl benzene based resin containing bicine groups has been prepared and its analytical properties investigated. The pH dependence of sorption of metal on the resin has been determined for Cu(II), Fe(II), Ni(II), Co(II), Zn(II), Hg(II) and Pb(II). The important characteristics of the resin are fast equilibrium, high selectivity and small volume change between its hydrogen and metal forms. These enable it to be applied to the rapid concentration of trace amounts of these metal ions. It shows promise for the separation of lead from other metal ions.     

Separation and analysis of aluminium(III) by cation exchange ion chromatography

A method for the determination of aluminium(III) ions based on separation by cation exchange column chromatography and detection by conductivity detector has been developed. It is fast and reliable, and can be used for the separation and analysis of aluminium(III) ions from other metal ions like Mg(II), Mn(II), Zn(II), Co(II), Ca(II), Sr(II), rare earth elements like Lu(III), Tm(III), and Gd(III), which are eluted at different times and so do not interfere. Effect of p-phenylene diamine concentration present in the eluent, presence of other metal ions and effect of various anions present in the injection sample on the separation and analysis of aluminium(III) ions have also been studied.     

Solvent extraction and separation of gallium(III), indium(III), and thallium(III) with tributylphosphate

A systematic study has been made of the solvent extraction behaviour of milligram amounts of gallium(III), indium(III), and thallium(III) with TBP from hydrochloric acid, and of thallium(III) from nitric acid, sulphuric acid and buffer solutions of different pH. The effect of the metal ion concentration, acid concentration, reagent concentration, salting-out agent, and diverse ions have been critically examined. A scheme for separation of gallium(III), indium(III), and thallium(III) from each other and for their determination is proposed.     

Richment and Determination of Trace of Cadmium in Environmental Water with Silica Immobilized Benzene-Diazo-Dmino-Azobenzene

Chelating reagents supported (or banded) on silica gel for preconcentration and separation of trace amount of metal ions has been reported recent years. These methods improve analytical sensitivity and selectively greatly,and make it possible for many trace elements to be determineted in the Environmental fieled.     

Studies of Hydrous Zirconium Oxide. I. Thin-Layer Chromatography of Some Metal Ions on Hydrous Zirconium Oxide: Quantitative Separation of Bi(III) from Several other Metal Ions

Abstract

The analytical potentiality of hydrous zirconium oxide as an ionexchanger has been investigated by thin-layer chromatographic (TLC technique. Binder-free thin-layers of hydrous zirconium oxide are useful for 25 ternary and 12 quaternary separations. Quantitative separation of Bi (III) from some ternary and quaternary mixtures of metal ions has been achieved.     

Controlled-pore silica glass modified with N-propylsalicylaldimine for the separation and preconcentration of trace Al(III), Ag(I) and Hg(II) in water samples.

Controlled-pore silica glass modified with N-propylsalicylaldimine (SCPSG) has been investigated as a surface-active matrix for the separation of some metal ions. The porous silica glass base was confirmed to have better stability towards hydrolysis in aqueous solution buffered at pH=9 in comparison to silica gel, which showed twice the surface area of controlled-pore silica glass. The different analytical parameters affecting the batch mode separation and preconcentration of trace Al(II), Ag(I) and Hg(II) in environmental samples using SCPSG, prior to their determination using inductively coupled plasma mass spectrometry (ICP-MS), were studied. The optimum conditions are pH 9.0 +/- 0.1, time of stirring 30 min and the eluent concentration 0.5 mol dm(-3) HNO3. The ion-exchange capacity of SCPSG with respect to Al(III), Ag(I) and Hg(II) was 0.27, 0.18 and 0.23 mmol g(-1), respectively. The recovery values for the metal ions were 96.8 +/- 0.86, 98.1 +/- 0.60 and 96.2 +/- 1.06%, and the analytical detection limits were 26.1, 1.49 and 0.44 pg cm(-3), respectively, for a preconcentration factor of 100. The method has been applied to the determination of the investigated metal ions in natural water samples as well as certified and reported samples and the results were found to be accurate.     

Gravimetric determination of thorium and cerium with n-benzoylphenylhydroxylamine

Benzoylphenylhydroxylamine has been used for the precipitation of thorium and trivalent cerium; the precipitates are ignited to the corresponding metal dioxide and weighed. Ceric ions are reduced before precipitation. The gravimetric separation of thorium and cerium is effected by precipitation at different pH values.     

Surfactant cloud point extraction and preconcentration of organic compounds prior to chromatography and capillary electrophoresis

The use of preconcentration steps based on phase separation by the cloud point technique offers a convenient alternative to more conventional extraction systems. It has been used successfully for the preconcentration of species of widely differing character and nature, such as metal ions, proteins and other biomaterials, or organic compounds of strongly differing polarity. Here we address the most recent analytical applications of this methodology when used as an isolation and trace enrichment step prior to the analysis of organic compounds (polycyclic aromatic hydrocarbons, polychlorinated compounds, pesticides, phenolic derivatives, aromatic amines, vitamins, etc.) via liquid and gas chromatography or capillary electrophoresis.     

氧化铁磁性纳米粒子的制备、表面修饰及在分离和分析中的应用

氧化铁磁性纳米粒子通过表面化学修饰得到无机、有机或聚合物壳包覆在其表面。其中的壳结构既具有生物适应性,又具有可键合生物分子如细胞、蛋白质、酶、抗体和核酸的活性基团,而核具有磁性特性。本文总结了氧化铁磁性纳米粒子的制备方法,介绍了其表面化学修饰及在分离和分析应用的最新进展。     

Synthetic Inorganic Ion-Exchangers XV. Thin-Layer Chromatography of Metal Ions on Thorium Tungstate: Quantitative Separation of Hg(II) from Several Other Metal Ions

Abstract

The analytical application of Thorium tungstate as an ion exchanger has been explored by thin-layer chromatographic (TLC) technique. Binder-free thin layers of thorium tungstate have been employed for some important binary and ternary separations. Quantitative separation of Hg(II) from the mixture of several other metal ions has been achieved.     

Separation of Pd(II) and Tl (III) from Various Metal Ions on Hydrous Zirconium Oxide Column

Abstract

The utility of hydrous zirconium oxide for the separation of metal ions has been explored. The Kd-values from different concentrations of chloride ions(pH-2) have been determined. On the basis of the sorption data Pd (II) and Tl (III) have been quantitatively separated from a number of metal ions. The representative elution curves are given and the recovery of the metal ions is reported.     

Chromatographic separation of certain metal ions using a bifunctional quaternary ammonium-sulfonate mixed bed ion-exchanger

The separation behaviour of Pb(2+), Cu(2+), Cd(2+), Co(2+), Zn(2+) and Ni(2+) on bifunctional quaternary ammonium-sulfonate mixed ion-exchangers (Dionex, IonPac CS5 and CG5) was studied using different eluents including solutions of oxalic acid, potassium oxalate, sodium oxalate and ammonium oxalate. Separated metal ions were followed by using 4-(2-pyridylazo) resorcinol (PAR) as post-colouring complex. The retention factors of different ions proved to be dependent on the pH, concentration, nature of each complexing agent, and to less extent on eluent flow rate. The retention behaviour and separation mechanism of complexed metal analytes are discussed in the light of the stability of metal complexes and the ligand complexing ability of used eluent. Comparison between various mobile phases is evaluated, and both sodium and potassium oxalate can be used successfully for simultaneous separation of studied metals with good resolution within short elution periods. The method can be used in different applications including analysis of bottled water from different resources.