Detection of Hg(II) amidst several heavy and toxic metal ions after their selective separation by chromatography: rationalization of separation factors in terms of Density Functional (hardness) Index

Abstract

Ascending paper chromatography of Hg+2 has been performed with mixed acids as developing mobile phase. Effects of temperature, concentration, and composition of the mobile phase on Rf values have been investigated. Hg+2 has been selectively separated from several synthetic binary and multicomponent mixtures containing the toxic and heavy metal ions. Often these metal ions remain associated with it in its ores and alloy samples. Hg+2 in trace level has been separated and detected from blood serum containing the congeners Zn+2, Cd+2, Pb+2, Bi+3, Th+4, Tl+3, and Cu+2. On the basis of the difference in the migration of the spots on the paper, twenty difficult separations have been achieved. Several thermodynamic parameters, ΔG, ΔH, and ΔS have been determined by differential variation of radii of the spot with respect to temperature utilizing the thermodynamic relationship. The partition equilibrium constant was also determined. Metal ions were detected by borohydride reduction on the paper strip. Separation factors have been correlated in terms of DesityFunctional (corrected hardness, η∗) Index. From η∗, hydrated radii of the metal ions have been determined. A plausible mechanism for the differential migration of diverse metal ions has been suggested.