Ali Mohammad

Thin-Layer Chromatography of Metal Ions in Formic Acid Medium on Impregnated and Unimpregnated Silica Gel G: Semiquantitative Determination of Fe3+, Cd2+, Th4+, Al3+, Zn2+, UO2+ 2, VO2+, Ce4+, and Ni2+

Abstract The adsorption behavior of metal ions in the formic acid-sodium formate system using unimpregnated as well as impregnated silica gel G as thin layers has been studied. A remarkable result of this study is the dramatic selectivity of impregnated silica gel G thin layers when compared to the corresponding unimpregnated silica gel G thin layers. This impregnation effect provides us with a new adsorbent phase which is sufficiently stable in the formic acid-sodium formate medium. Some important ternary separations have been achieved on silica gel G thin layers. Al3+, Ni2+, Fe3+, and Pb2+ have been qualitatively separated from mixtures of other ions. Cu2+ has been selectively separated on impregnated silica gel G thin layers. The semi-quantitative determination of nine metal ions on impregnated silica gel G layers has also been attempted.

THIN-LAYER CHROMATOGRAPHY OF AMINO ACIDS: A REVIEW

Thin-layer chromatography is a versatile separation technique and is compatible to almost all types of compounds available in nature. This review presents numerous chromatographic systems developed for the analysis of amino acids. The stationary phases, solvent systems, and detection reagents used by the various chromatographers are incorporated in this review. From the available literature, it is obvious that amino acids have been greatly analyzed by thin-layer chromatography.

Thin-layer chromatographic separation, colorimetric determination and recovery of thiocyanate from photogenic waste, river and sea waters

Abstract TLC was used to study the retention behaviour of some inorganic anions (SCN − , NO 2 − , MnO 4 − , CrO 4 2− , Cr 2 O 7 2− , MoO 4 2− , Mo 7 O 24 6− , Fe(CN) 6 3− and Fe(CN) 6 4− ) and metal ions (Fe 3+ , Zn 2+ , Cu 2+ , Cd 2+ , Co 2+ , Hg 2+ , UO 2 2+ VO 2+ , Ag + , Mn 2+ and Bi 3+ ) on cellulose, Kieselguhr and their mixtures. Mixed solvent systems containing 0.1 M NH 4 OH and CH 3 COCH 3 were used as eluents. SCN − separated from other ions was determined by spectrophotometry at 460 nm using acidic FeCl 3 solution as chromogenic reagent. Beers law was followed up to 11.84 ppm of SCN − . The proposed TLC-colorimetric method was applied to fortified samples of photogenic waste, river and seawaters.

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.

Fresh evidence for proposed zwitterionic intermediates.

A new selective and sensitive method for the detection of aliphatic amines has been developed with chloride-form anion-exchange resins and 2,4-dinitrotoluene. The reaction with tertiary amines can only be explained in terms of hitherto postulated zwitterionic intermediates.

Water-in-Oil Microemulsion as Mobile Phase in Thin-Layer Chromatographic Retention Studies of Anions

A water-in-oil (W/O) microemulsion, consisting of sodium dodecyl sulphate (SDS)/1-pentanol/water/heptane, has been used as mobile phase for the separation of inorganic anions from their binary mixtures, for example, IO4−-NO2−, IO4−-BrO3−, IO4−-I−, MnO4−-BrO3−, MnO4−-NO2−, and MnO4−-Br−. The weight ratio, SDS/n-pentanol was kept constant at 1/2.46 for all compositions. The retention efficiency of anions on layers of silica gel G, alumina, microcrystalline cellulose, kieselguhr G, and mixtures of kieselguhr and cellulose in 4:1 and 3:2 ratios has been examined with the W/O microemulsion system as a mobile phase. Thin layers of kieselguhr were most useful for differential migration of anions. Quantitative separation of IO4− from accompanying ions, limits of identification, and dilution of few anions are reported. The effects of amines, phenols, and heavy metals on the separation efficacy of IO4− also have been investigated.

Determination of microquantities of mercury(II) with preliminary thin-layer chromatographic separation from mercury(I), lead(II), nickel(II), and copper(II) on acid-treated silica gel layers: recovery of mercury(II) from river waters and industrial wastewaters

Thin-layer chromatography in combination with spectrophotometry has been applied for the separation and estimation of Hg(II) using silica gel layers impregnated with 2% oxalic acid as stationary phase with an ethyl acetate:acetone:formic acid:water (8:7:4:1) solvent system. Separation of Hg(II) from Hg(I) and of Th4+ from UO22+ is not affected by the presence of common anions in the sample solution. Hg(II) has been successfully separated from Ni(II), Cu(II), and Pb(II) over a wide range of pH (0.5–7.0) of sample solution. An attempt has been made to recover Hg(II) from rivers and industrial wastewaters.

New inexpensive and selective sorbent phases for rapid thin layer chromatographic analysis of metal ions

Abstract New sorbent phases have been developed by impregnating silica gel G with different inorganic salts for the analysis of metal ions by thin layer chroma to graphy in carboxylic acids media. Thin layers prepared from silica gel G impregnated with ammonium chloride or barium nitrate show the unusual selectivity towards metal ions in comparison to the thin layers prepared from plain silica gel G or silica gel impregnated with silver nitrate or aluminium nitrate. Many qualitative separations

TLC separation of microgram quantities of iron(II) from milligram quantities of iron(III)

Abstract A TLC method has been developed for the separation of microgram quantities of Fe(II) from milligram quantities of Fe(III) by using formic acid-butanol-ethyl methyl ketone as mobile phase. The separation is not effected by the presence of chloride, bromide, sulfate, sulfite, acetate and phosphate ions. Good separation was achieved when the pH of the sample solution was kept near to 1.0.

Chromatography of anionic pollutants on silica gel layers: Selective microgram separation of NO2− and IO3−

Abstract Investigations regarding thin-layer chromatographic behavior of seventeen anions have been conducted on silica gel impregnated with inorganic salts such as copper sulfate, zinc sulfate, cobalt chloride, hexamine cobalt III chloride, and nickel chloride using mixed aqueous-organic eluents containing formic acid. The effect of mineral acids on the mobility of anions has also been studied by substituting formic acid with HCl, H2SO4, or HClO4 in the mobile phase. In addition to microgram separation of NO2− and IO3− from various anionic species, some other important qualitative separations have also been realized. The effect of pH of the sample solution and loading amount of IO3−, BrO3−, NO2−, and I− on their RF values has been investigated. The limits of identification for all anions on impregnated layers have been determined. Semiquantitative determination of NO2− and BrO3− have been attempted using the spot area measurement method.