TLC separations of some metal ions with aqueous and aqueous-organic solvent systems containing formic acid

Mohammad, Ali; Fatima, Narjis

doi:10.1007/bf02257310

Cited by 10 publications

(1 citation statement)

References 17 publications

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“…Many separations utilize silica gel supports and focus on manipulating the composition of the mobile phase to improve the separation, which is not always practical. [12][13][14] Others have modified the inorganic support with chelating ligands [15][16][17][18][19][20][21][22][23] and/or utilized chelation ion chromatography (CIC) to separate and quantify mixtures containing transition and heavy metals. [24][25][26][27][28][29] CIC relies on the competition between an immobilized chelating ligand, such as iminodiacetic acid, a β-diketone, or an amine, in the stationary phase and another chelating agent, such as picolinic or dipicolinic acid or trifluoroacetylacetone, in the mobile phase.…”

Section: Introductionmentioning

confidence: 99%

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

Stegall

Ashraf

Moye

et al. 2016

Journal of Chromatography A

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Stationary phase gradients for chelation thin layer chromatography (TLC) have been investigated as a tool to separate a mixture of metal ions. The gradient stationary phases were prepared using controlled rate infusion (CRI) from precursors containing mono-, bi-, and tri-dentate ligands, specifically 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl] ethylenediamine, and N-[3-(trimethoxysilyl)propyl] diethylenetriamine. The presence and the extent of gradient formation were confirmed using N1s X-ray photoelectron spectroscopy (XPS). XPS results showed that the degree of modification was dependent on the aminosilane precursor, its concentration, and the rate of infusion. The separation of four transition and heavy metals (Co(2+), Pb(2+), Cu(2+), and Fe(3+)) on gradient and uniformly modified plates was compared using a mobile phase containing a stronger chelating agent, ethylenediaminetetraacetic acid (EDTA). The retention of the metal ions was manipulated by varying the surface concentration of the chelating ligands. The order of retention on unmodified plates and on plates modified with a monodentate ligand was Fe(3+)>Cu(2+)∼Pb(2+)∼Co(2+), while the order of retention on plates modified with bi- and tri-dentate ligands was Fe(3+)>Cu(2+)>Pb(2+)∼Co(2+). Fe(3+) and Cu(2+) were much more sensitive to the concentration of chelating ligand on the surface (displaying lower Rf values with increasing ligand concentration) than Pb(2+) and Co(2+). Complete separation was achieved using a high concentration of the tridentate ligand coupled with a longer time for modification, yielding a retention order of Fe(3+)>Cu(2+)>Co(2+)>Pb(2+).

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Section: Introductionmentioning

confidence: 99%

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

Stegall

Ashraf

Moye

et al. 2016

Journal of Chromatography A

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Cation thin-layer chromatography in mixed organic solvents containing s-butylamine: Separation of Zn(II) from Cd(II) and Cu(II)

Mohammad¹,

Fatima²

1987

Chromatographia

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Micellar thin‐layer chromatographic separation of heavy metal cations: Effect of organic and inorganic additives on migration behavior

Mohammad

Iraqi

Khan

1999

J Surfact & Detergents

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The migration behavior of heavy metal cations on cellulose layers using aqueous micellar, hydro-organic, and water-organic-surfactant mobile phases was investigated. Anionic, cationic, and nonionic surfactant systems were examined over a 0.001-5% concentration range. Brij-35, a nonionic surfactant capable of forming charged complexes with some metal ions, was identified as the best surfactant. The effect of the presence of organic additives, such as dimethylsulfoxide, dimethylformamide, methanol and acetone, on the mobility of metal ions was also studied. Acetone was found to be the most effective additive at 10% concentration with 3% Brij. Quantitative determination of UO 2 2+ by spectrophotometry after preliminary thin-layer chromatographic (TLC) separation from Fe 3+ and Hg 2+ was also performed. A maximal recovery of 93% was obtained. This TLC method is rapid, with development times averaging 2 min.Paper no. S1098 in JSD 2, 523-529 (October 1999). KEY WORDS:Acetone, Brij-35, DMSO, heavy metal cations, micelles, TLC, uranium.Micellar liquid chromatography (MLC) has increased in popularity because of its unique advantages, such as the capability to simultaneously separate ionic and nonionic compounds and to provide faster analysis, higher detection sensitivity, and selectivity (1-5). The most fascinating feature of micellar systems is their dual hydrophobic and hydrophilic character, which provide electrostatic and hydrophobic sites of interaction within the aqueous mobile phase, resulting in unique separation capabilities of both ionic and nonionic solutes. As a result, micellar mobile phases have been extensively used in reversed-phase chromatographic separation of various organic compounds. In comparison, the use of micellar mobile phases in inorganic chromatography has been limited. Efficiency of mobile phases in the separation of cations (6,7) and anions (8,9) has been reported and reviewed by Okada (10). Mullins and Kirkbright (11) used MLC as an alternative to ion chromatography for the separation of several inorganic anions using a cationic micellar eluent. Kirkman et al. (12) used a variety of micellar eluants to examine the chromatographic behavior of ionic, nonionic, chelated, and organometallic metal species. Although micellar mobile phases offer enhanced selectivity, they suffer from a serious loss of efficiency when compared to traditional hydro-organic mobile phases. Dorsey et al. (13) reported that addition of low concentrations of different organic solvents to micellar mobile phases improves efficiency by reducing the adsorbed amount of emulsifier (surfactant). This unique phenomenon in MLC was attributed to the existence of a competing equilibrium in MLC and an influence of micelles on the role of organic modifiers. Khaledi et al. (14) observed simultaneous enhancement of separation selectivity and solvent strength in MLC using hybrid eluants comprising cationic or anionic micellar-organic solvents for different groups of ionic and nonionic compounds.A few studies reported the use of surfac...

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TLC separations of some metal ions with aqueous and aqueous-organic solvent systems containing formic acid

Cited by 10 publications

References 17 publications

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

Cation thin-layer chromatography in mixed organic solvents containing s-butylamine: Separation of Zn(II) from Cd(II) and Cu(II)

Micellar thin‐layer chromatographic separation of heavy metal cations: Effect of organic and inorganic additives on migration behavior

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