Thin Layer Chromatography of Some Metals on Silica Gel Layers Impregnated with Phenolic Acids

Abstract

Thin layer chromatography of metals was performed on silica gel impregnated with phenolic acids. The results obtained can be used to gain a better insight into the behaviour of metals under the proposed chromatographic conditions and as an additional system for their separation.     

Retention of Some Metal Ions and Their Separation on Silica Gel Modified with Acid Red 88

 Acid Red 88 is strongly extracted by chloroform solutions of Aliquat 336 by an ion exchange mechanism and for its reextraction from the ion pair formed, relatively high concentrations of mineral acids are required. By impregnation of silica with the ion pairs between the cation of Aliquat 336 and the anion of the dye a chelating sorbent for metal ions can be obtained. The sorbent prepared may be successfully used for separation of mixtures of various metal ions by the column extraction chromatography technique, additional purification of sodium and potassium salts from ions of heavy metals and for concentration of trace amounts of ions of various metals from aqueous solutions followed by their quantitative determination. The sorbent can be used repeatedly in the process of sorption and desorption of metal ions (especially those forming less stable complexes with the reagent) after regeneration with solutions of perchloric acid. Received January 28, 1998. Revision March 1, 1999.     

Thin Layer Chromatography of Purines on Silica Gel G Impregnated with Transition Metal Ions; Assay of Caffeine and Theophylline in Pharmaceutical Formulations

This study was undertaken to develop thin layers of silica gel G impregnated with transition metal ions for separation, identification and estimation of purines. The influence of transition metal ions and eluting solvents on chromatographic behaviour (hR_f) has been studied. The method was applied for qualitative analysis of purines in the mixtures and quantitative analysis of purine bases in the mixture as well as in pharmaceutical formulations. The results were compared statistically with those obtained by official methods. The method is simple, reproducible, and accurate within 1.3 ± 0.6%.     

A Comparison of Amino Acid Separations on Silica Gel,Cellulose, and Ion Exchange Thin Layers

Abstract

Separations of amino acids on silica gel, high performance silica gel, preadsorbent silica gel, microcrystalline and fibrous cellulose, and Fixion strong acid cation exchange layers were compared under standardized conditions using a mixture of the nine essential acids and a more complex 18-component mixture. Fixion layers were evaluated using three different development conditions, and loading studies of raw urine were carried out on all of the layers. Tables and figures are presented illustrating which amino acids can be resolved in each of the chromatographic systems.     

Reverse Phase Thin-Layer Chromato-Graphy of some Metal Ions on Butyl-Amine Impregnated Silica Gel G in Formic Acid Medium

Abstract

Reversed phase thin layer chromatography of metal ions have been performed on s-butylamine and t-butylamine impregnated silica gel thin layers in formic acid and sodium formate systems. Separation potential of impregnated silica gel thin layers was explored. Impregnated silica gel layers were found to be more selective (strongly sorbing) than unimpregnated silica gel chromo-toplates. Several important binary and ternary separations were achieved on impregnated thin layers.     

Retention Behavior of Metal Ions on Tri-n-Butyl Phosphate and Tri-n-Butyl Amine-Impregnated Silica Gel G Layers: Quantitative Separation of Lead from Other Metal Ions and Synthetic Alloys

JPC – Journal of Planar Chromatography – Modern TLC - The retention behavior of 40 metal ions has been studied on tri-n-butyl phosphate (TBP) and tri-n-butylamine (TBA)-impregnated...     

Analysis of Quaternary Ammonium Compounds by Ion-Pair Thin Layer Chromatography on Silica Gel

Abstract

A general approach to the chromatographic analysis of quaternary ammonium compounds on silica gel thin layers is described. The quaternary cations migrate as ion pairs with bromide or iodide as counter ions. Methanol or chloroform-methanol mixtures serve as developing solvents, in which excess amounts of NaBr or NaI are dissolved. If the solvent cannot dissolve sufficient quantities of halide salts, the latter can be sprayed onto the plate as a methanol solution prior to development. The separation patterns of the quaternary ammonium compounds can be influenced by the choice of counter ion and by the choice of the organic solvent components.     

The Behaviour of Some Phenolic Acids and Aldehydes on Thin Layers of Silica Gel Impregnated with Fe(III)

Abstract

The behaviour of phenolic aldehydes and acids commonly found in lacustrine sediments as degradation products of lignine was tested by thin layer chromatography on silica gel plates plain and impregnated with Fe(III) in different solvent systems. The differences expressed as R_i values can be used as one of the parameters in the identification of some phenolic aldehydes or acids.     

High-Performance Chelation Chromatography of Metal Ions on Sorbents with Grafted Iminodiacetic Acid

The chromatographic behavior of some alkaline-earth, transition, heavy, and rare-earth metals on a number of complexing sorbents containing surface iminodiacetic acid (IDA) functional groups is studied. The conditions under which metal retention is determined by complexation on the sorbent surface were established, and the main principles of a new variant of the liquid chromatography, i.e., high-performance chelation ion chromatography (HPCIC), are formulated. The efficiency and selectivity of separation of the metal ions are considered depending on the type of the IDA bonding, the sorbent matrix parameters, the eluent composition, and the temeprature of the chromatographic column. Under optimal conditions, the metal retention is shown to linearly correlate with the stability constants of the respective complexes in the double-logarithmic scale. The application of HPCIC to the analysis of multicomponent systems is considered.     

Thin Layer Chromatography of Metal Ions Complexed with Anils Part - VI

Abstract

Thin layer chromatographic detection, separation and determination of Ti(IV), UO₂(II), Au(III) and Hg(II) complexes with λ - and β - naphthylanils of methylenediglyoxal have been made on silica gel layers. No locating agent was used as the complex spots were self evident in day light.     

硅胶中六种金属离子反王水消解-离子色谱检测方法的研究

本文建立了硅胶中金属离子反王水消解-离子色谱检测的方法.系统研究了硅胶的最佳前处理条件,选择消解试剂为氢氟酸和反王水,还原剂为抗坏血酸,实现了Na+、Zn2+、K+、Fe2+、Mg2+和Ca2+六种金属离子基线分离.该方法简便快速、灵敏、重现性好.进一步以该方法对实际硅胶样品中微量金属离子测定,获得较好的结果.     

Ion-Pair Chromatography of Nitrogen-Bridged Compounds on Silica Gel

Abstract

New adsorption operations of high-performance ionpair chromatography have been investigated, using certain types of pharmacologically active nitrogen-bridged compounds. Various chromatographic data are reported. The effect of the counter ion concentration has been studied. Numerous examples of separations are presented.     

The Effect of Substituent Groups on the Migration of Metal Ions in Thin Layer Chromatography

Abstract

A reverse phase thin layer partition chramotography has been performed on metal ions using silica gel G as an adsorbent. The effect of chlorosubstituent groups on the migration of cations has been studied. The use of aqueous solutions of acetic acid, monochloro, dichloro and trichloro acetic acid in the solvent system revealed profound effect of substituent groups on the R_f values of metal ions. The effect of concentration and pH of the mobile phases have been studied. Many qualitative ternary separations have been sucessfully achieved.     

TLC Separations of Amino Acids on Silica Gel Impregnated Layers

Abstract

Copper sulphate and polyamide were tried as impregnants for improving the separation of twenty amino acids on silica gel ‘G’ layers using a new solvent system MeOH-BuOAc-AcOH-Pyridine(20:20:10:5). Tables are presented to illustrate the improvement in resolution of amino acids on silica gel plates.     

Separations in Thin Layer and High Performance Liquid Chromatography Using Alkyl Silica Gel Bonded Phases

Abstract

Separations in thin layer (TLC) and high performance liquid chromatography (HPLC) using alkyl bonded phases were carried out under optimum solvent conditions for each of three phases, RP-2, RP-8 and RP-18. The phases were tested for their efficiency and resolving power using three groups of compounds in three binary organic-water mobile phases. The organic solvents were acetonitrile, methanol and tetrahydrofuran, which are widely used as solvent modifiers in reversed phase liquid chromatography.

The results showed that, unlike HPLC, TLC using RP-18 plates was the most, and RP-2 plates the least, efficient. A naphthalene and biphenyl mixture which was resolved by HPLC using any of the three solvents and columns was not resolved by TLC using any plate or solvent combination, unless the plate was prewashed with an organic modifier. The addition of NaCl (1–2% wt/vol) to the solvent for TLC speeded development unless an alcohol was used, but did not greatly affect the separation.     

Prediction of KSP from Rf Values: Thin Layer Chromatography of 47 Metal Ions on Stannic Arsenate in Aqueous Hydrochloric Acid Systems

Abstract

The adsorption behaviour of 47 metal ions has been studied in aqueous HCl systems using stannic ersenate layers. The effect of solvent pH on R_f alongwith the complexation effect of HCl has been investigated. On the basis of R_f values the K_SP of some metel arsenates have been predicted. HCl has been utilized to resolve some binary and ternary mixtures such as Be²⁺ - Mg²⁺, Zr⁴⁺ - La³⁺, Th⁴⁺ - Ce⁴⁺, Th⁴⁺ - UO²⁺ ₂, Cr³⁺ - Mo⁶⁺ or W⁶⁺, Sb³⁺ - Bi³⁺ - Cd²⁺ and Ag⁺ - Cu²⁺ - Cd²⁺.     

Separation Studies of Metal Ions in Sodium Thioglycolate Medium by Thin Layer Partition Chromatography

Abstract

A thin layer partition chromatographic method has been developed for separation of Fe(III), Ni(II), Zn(II), Cu(II), Pb(II) and Mn(II) on thin layers of silica gel-G as an adsorbent. The R_f values were determined using 0.01–0.2 aqueous solution of sodium thioglycolate as a mobile phase. The dependence of R_f values on the migration time, pH and concentration of mobile phase has been studied. The optimum conditions for possible 3-component separation have been determined. Metal ions have been separated, detected, eluted and quantitatively determined by atomic absorption spectroscopy. The present method was applied to the separation and determination of zinc in forensic samples.     

Outer-Sphere Ligand Exchange Chromatography on Bonded Chiral Silica Gel

Abstract

A bonded chiral phase for HPLC, obtained by reaction between a porous silica gel modified with N(aminoethylamino)propyl groups, and A(+)[Co(en)₂(NO₂)] Br, was prepared in order to sepa rate optical isomers by a outer-sphere complex mechanism. The extent of the stereoselectivity of this support was tested by sampling racemates of organics acids and of tris-oxalate complexes of cobalt(III) and chromium(III). Good resolution was achieved when strong interactions of the solute (tri-oxalates complexes) with the support were involved.     

Simultaneous Analysis of Some Metal Ions in Piperidinedithio-carbamate Chelates by Reversed-Phase Liquid Chromatography

Simultaneous analysis of Ni(Ⅱ), Pd(Ⅱ), Co(Ⅱ),Cu(Ⅱ) and Hg(Ⅱ) in piperidinedithio-carbamate(PDTC) chelates were investigated by reversed phase HPLC. The optimum conditions for the separation of PDTC metal chelates were examined with respect to the pH, extraction solvent and mobile phase strength. The metal ions in mixtures at trace level, chelated with PDTC, were successfully separated on Novapak Cl8 column using methanol/water(75:25) mixture as mobile phase. PDTC metal chelates were eluted in an acceptable range of capacity factor value (0