Thin-layer chromatography of heavy metal-diethyl dithiocarbamate complexes

Thin-layer chromatographic behaviour of some heavy metal-diethyldithiocarbamate complexes has been studied usin g calcium carbonate, calcium citrate, calcium oxalate, calcium phosphate dibasic, calcium sulphate dehydrated, cellulose and silica gel G as stationary phase and acetonitrile, acetone, benzene, butanol, chloroform, 1,4-dioxan, di st ill ed water, ethyl acetate, EDT A-ammonia buffer (I : I), methanol and propanol as mobile phase. Cd(II) and Pb(H) from Mn(II), Fe( III), Co(! I). Ni (Ir ), Cu(H), Hg(l) and Hg(H) have been practicall y separated on cellulose impregnated with sodiu diethyldithio­ carbamate in eth yl acetate. Recently, Espinola et al. 1 have developed immobilized dithiocarbamate by the reaction of 3propy lethylenedi amine group, covalently bonded to silica gel G, with carbon disulphide in toluene. This modified surface has 6.7 x 10-4 mole g·' ligand sites available to extract Co(II), Ni(II), Cu(II) and Zn(II) in water. The following cation-exchange process occurs in ethanolic solution: Si (edAh (soln) + M 2 + (soln)~ Si (edh M (Soln) + 2A + (soln) where the tetramethyl ammonium cation (A+), ionically bonded to the surface, is displaced by the M 2 + and equivalence of this exchange is related to the number of available ligand groups anchored on the matrix. The cations are sulphur-bonded to the anchored ligand. The cations-exchange properties observed on anchored dithiocarbamate are very simil ar to the general dithiocarbamate behaviour seen in dithiocarbamate coordination chemistry. Six years later in 1999, Wen et a!? prepared a new ion­ exchange chelating fibre with polyacrylonitrile and used it for the simultaneous preconcentration of Be, Mn, Co, Cu, Ga, Ag, Cd, In, IPb and Bi in sea water. These metal ions can be concentrated 200 times in a short period of time. It becomes a promising method by coupling with ICP-MS for the determination of trac e elements in sea water. Elena et az3 . discussed several analytical techniques for the analysis of heavy metal ions in water. However, no efforts have been