Focussing Review

Separation Studies of Transition Metal Ions with Cationic Micellar Eluents in Normal Phase Thin.Layer ChromatographyMiniaturization of Separation Systems and Its Applications

Ali Mohammad*, Vineeta Agrawal and Nahed Jabeen

Analytical Research Laboratory, Department of Applied Chemistry Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh-202002, INDIA

Abstract:

The analytical potential of surfactant.mediated mobile phase in thin layer chromatographic separation and identification of metal cations has been investigated. Effects of (a) concentration of surfactant in the mobile phase, (b) acidity or basicity of surfactant.containing developer medium, and (c) the presence of electrolyte and non electrolyte additives in the mobile phase systems on the mobility of metal cations were examined. Better chromatographic performance of hybrid.mobile phase systems comprising of micelle (3% CTAB) .water.alcohol (methanol, ethanol, propanol or butanol) over aqueous micellar mobile phase systems was observed. The thin layer chromatographic (TLC) system comprising silica gel G as stationary phase and 3% aqueous cetyltrimethylammonium bromide (CTAB) + propanol (80+20) as mobile phase was identified as the most favourable for the separation of mixtures of Zn2+, Cd2+ and Hg2+. Semiquantitative determination of Zn2+, Cd2+ and Hg2+ by visual comparison of colour intensities on the TLC plates as well as by measurement of spot area was attempted. Identification of Zn2+, Cd2+ and Hg2+ from river water, industrial wastewater and sulphide sludge with preliminary separation has been achieved. The method has been successfully applied for identification of Hg, Zn and Cd in synthetic ores such as cinnabar (HgS), zinc blende (ZnS) and greenoekite (CdS). The dilution and detection limits of Zn2+, Cd2+ and Hg2+ on silica gel layers have also been evaluated.

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